v4.19.13 snapshot.
diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c
new file mode 100644
index 0000000..b5f6382
--- /dev/null
+++ b/drivers/scsi/scsi_lib.c
@@ -0,0 +1,3627 @@
+/*
+ * Copyright (C) 1999 Eric Youngdale
+ * Copyright (C) 2014 Christoph Hellwig
+ *
+ * SCSI queueing library.
+ * Initial versions: Eric Youngdale (eric@andante.org).
+ * Based upon conversations with large numbers
+ * of people at Linux Expo.
+ */
+
+#include <linux/bio.h>
+#include <linux/bitops.h>
+#include <linux/blkdev.h>
+#include <linux/completion.h>
+#include <linux/kernel.h>
+#include <linux/export.h>
+#include <linux/init.h>
+#include <linux/pci.h>
+#include <linux/delay.h>
+#include <linux/hardirq.h>
+#include <linux/scatterlist.h>
+#include <linux/blk-mq.h>
+#include <linux/ratelimit.h>
+#include <asm/unaligned.h>
+
+#include <scsi/scsi.h>
+#include <scsi/scsi_cmnd.h>
+#include <scsi/scsi_dbg.h>
+#include <scsi/scsi_device.h>
+#include <scsi/scsi_driver.h>
+#include <scsi/scsi_eh.h>
+#include <scsi/scsi_host.h>
+#include <scsi/scsi_transport.h> /* __scsi_init_queue() */
+#include <scsi/scsi_dh.h>
+
+#include <trace/events/scsi.h>
+
+#include "scsi_debugfs.h"
+#include "scsi_priv.h"
+#include "scsi_logging.h"
+
+static struct kmem_cache *scsi_sdb_cache;
+static struct kmem_cache *scsi_sense_cache;
+static struct kmem_cache *scsi_sense_isadma_cache;
+static DEFINE_MUTEX(scsi_sense_cache_mutex);
+
+static void scsi_mq_uninit_cmd(struct scsi_cmnd *cmd);
+
+static inline struct kmem_cache *
+scsi_select_sense_cache(bool unchecked_isa_dma)
+{
+ return unchecked_isa_dma ? scsi_sense_isadma_cache : scsi_sense_cache;
+}
+
+static void scsi_free_sense_buffer(bool unchecked_isa_dma,
+ unsigned char *sense_buffer)
+{
+ kmem_cache_free(scsi_select_sense_cache(unchecked_isa_dma),
+ sense_buffer);
+}
+
+static unsigned char *scsi_alloc_sense_buffer(bool unchecked_isa_dma,
+ gfp_t gfp_mask, int numa_node)
+{
+ return kmem_cache_alloc_node(scsi_select_sense_cache(unchecked_isa_dma),
+ gfp_mask, numa_node);
+}
+
+int scsi_init_sense_cache(struct Scsi_Host *shost)
+{
+ struct kmem_cache *cache;
+ int ret = 0;
+
+ cache = scsi_select_sense_cache(shost->unchecked_isa_dma);
+ if (cache)
+ return 0;
+
+ mutex_lock(&scsi_sense_cache_mutex);
+ if (shost->unchecked_isa_dma) {
+ scsi_sense_isadma_cache =
+ kmem_cache_create("scsi_sense_cache(DMA)",
+ SCSI_SENSE_BUFFERSIZE, 0,
+ SLAB_HWCACHE_ALIGN | SLAB_CACHE_DMA, NULL);
+ if (!scsi_sense_isadma_cache)
+ ret = -ENOMEM;
+ } else {
+ scsi_sense_cache =
+ kmem_cache_create_usercopy("scsi_sense_cache",
+ SCSI_SENSE_BUFFERSIZE, 0, SLAB_HWCACHE_ALIGN,
+ 0, SCSI_SENSE_BUFFERSIZE, NULL);
+ if (!scsi_sense_cache)
+ ret = -ENOMEM;
+ }
+
+ mutex_unlock(&scsi_sense_cache_mutex);
+ return ret;
+}
+
+/*
+ * When to reinvoke queueing after a resource shortage. It's 3 msecs to
+ * not change behaviour from the previous unplug mechanism, experimentation
+ * may prove this needs changing.
+ */
+#define SCSI_QUEUE_DELAY 3
+
+static void
+scsi_set_blocked(struct scsi_cmnd *cmd, int reason)
+{
+ struct Scsi_Host *host = cmd->device->host;
+ struct scsi_device *device = cmd->device;
+ struct scsi_target *starget = scsi_target(device);
+
+ /*
+ * Set the appropriate busy bit for the device/host.
+ *
+ * If the host/device isn't busy, assume that something actually
+ * completed, and that we should be able to queue a command now.
+ *
+ * Note that the prior mid-layer assumption that any host could
+ * always queue at least one command is now broken. The mid-layer
+ * will implement a user specifiable stall (see
+ * scsi_host.max_host_blocked and scsi_device.max_device_blocked)
+ * if a command is requeued with no other commands outstanding
+ * either for the device or for the host.
+ */
+ switch (reason) {
+ case SCSI_MLQUEUE_HOST_BUSY:
+ atomic_set(&host->host_blocked, host->max_host_blocked);
+ break;
+ case SCSI_MLQUEUE_DEVICE_BUSY:
+ case SCSI_MLQUEUE_EH_RETRY:
+ atomic_set(&device->device_blocked,
+ device->max_device_blocked);
+ break;
+ case SCSI_MLQUEUE_TARGET_BUSY:
+ atomic_set(&starget->target_blocked,
+ starget->max_target_blocked);
+ break;
+ }
+}
+
+static void scsi_mq_requeue_cmd(struct scsi_cmnd *cmd)
+{
+ struct scsi_device *sdev = cmd->device;
+
+ if (cmd->request->rq_flags & RQF_DONTPREP) {
+ cmd->request->rq_flags &= ~RQF_DONTPREP;
+ scsi_mq_uninit_cmd(cmd);
+ } else {
+ WARN_ON_ONCE(true);
+ }
+ blk_mq_requeue_request(cmd->request, true);
+ put_device(&sdev->sdev_gendev);
+}
+
+/**
+ * __scsi_queue_insert - private queue insertion
+ * @cmd: The SCSI command being requeued
+ * @reason: The reason for the requeue
+ * @unbusy: Whether the queue should be unbusied
+ *
+ * This is a private queue insertion. The public interface
+ * scsi_queue_insert() always assumes the queue should be unbusied
+ * because it's always called before the completion. This function is
+ * for a requeue after completion, which should only occur in this
+ * file.
+ */
+static void __scsi_queue_insert(struct scsi_cmnd *cmd, int reason, bool unbusy)
+{
+ struct scsi_device *device = cmd->device;
+ struct request_queue *q = device->request_queue;
+ unsigned long flags;
+
+ SCSI_LOG_MLQUEUE(1, scmd_printk(KERN_INFO, cmd,
+ "Inserting command %p into mlqueue\n", cmd));
+
+ scsi_set_blocked(cmd, reason);
+
+ /*
+ * Decrement the counters, since these commands are no longer
+ * active on the host/device.
+ */
+ if (unbusy)
+ scsi_device_unbusy(device);
+
+ /*
+ * Requeue this command. It will go before all other commands
+ * that are already in the queue. Schedule requeue work under
+ * lock such that the kblockd_schedule_work() call happens
+ * before blk_cleanup_queue() finishes.
+ */
+ cmd->result = 0;
+ if (q->mq_ops) {
+ /*
+ * Before a SCSI command is dispatched,
+ * get_device(&sdev->sdev_gendev) is called and the host,
+ * target and device busy counters are increased. Since
+ * requeuing a request causes these actions to be repeated and
+ * since scsi_device_unbusy() has already been called,
+ * put_device(&device->sdev_gendev) must still be called. Call
+ * put_device() after blk_mq_requeue_request() to avoid that
+ * removal of the SCSI device can start before requeueing has
+ * happened.
+ */
+ blk_mq_requeue_request(cmd->request, true);
+ put_device(&device->sdev_gendev);
+ return;
+ }
+ spin_lock_irqsave(q->queue_lock, flags);
+ blk_requeue_request(q, cmd->request);
+ kblockd_schedule_work(&device->requeue_work);
+ spin_unlock_irqrestore(q->queue_lock, flags);
+}
+
+/*
+ * Function: scsi_queue_insert()
+ *
+ * Purpose: Insert a command in the midlevel queue.
+ *
+ * Arguments: cmd - command that we are adding to queue.
+ * reason - why we are inserting command to queue.
+ *
+ * Lock status: Assumed that lock is not held upon entry.
+ *
+ * Returns: Nothing.
+ *
+ * Notes: We do this for one of two cases. Either the host is busy
+ * and it cannot accept any more commands for the time being,
+ * or the device returned QUEUE_FULL and can accept no more
+ * commands.
+ * Notes: This could be called either from an interrupt context or a
+ * normal process context.
+ */
+void scsi_queue_insert(struct scsi_cmnd *cmd, int reason)
+{
+ __scsi_queue_insert(cmd, reason, true);
+}
+
+
+/**
+ * __scsi_execute - insert request and wait for the result
+ * @sdev: scsi device
+ * @cmd: scsi command
+ * @data_direction: data direction
+ * @buffer: data buffer
+ * @bufflen: len of buffer
+ * @sense: optional sense buffer
+ * @sshdr: optional decoded sense header
+ * @timeout: request timeout in seconds
+ * @retries: number of times to retry request
+ * @flags: flags for ->cmd_flags
+ * @rq_flags: flags for ->rq_flags
+ * @resid: optional residual length
+ *
+ * Returns the scsi_cmnd result field if a command was executed, or a negative
+ * Linux error code if we didn't get that far.
+ */
+int __scsi_execute(struct scsi_device *sdev, const unsigned char *cmd,
+ int data_direction, void *buffer, unsigned bufflen,
+ unsigned char *sense, struct scsi_sense_hdr *sshdr,
+ int timeout, int retries, u64 flags, req_flags_t rq_flags,
+ int *resid)
+{
+ struct request *req;
+ struct scsi_request *rq;
+ int ret = DRIVER_ERROR << 24;
+
+ req = blk_get_request(sdev->request_queue,
+ data_direction == DMA_TO_DEVICE ?
+ REQ_OP_SCSI_OUT : REQ_OP_SCSI_IN, BLK_MQ_REQ_PREEMPT);
+ if (IS_ERR(req))
+ return ret;
+ rq = scsi_req(req);
+
+ if (bufflen && blk_rq_map_kern(sdev->request_queue, req,
+ buffer, bufflen, GFP_NOIO))
+ goto out;
+
+ rq->cmd_len = COMMAND_SIZE(cmd[0]);
+ memcpy(rq->cmd, cmd, rq->cmd_len);
+ rq->retries = retries;
+ req->timeout = timeout;
+ req->cmd_flags |= flags;
+ req->rq_flags |= rq_flags | RQF_QUIET;
+
+ /*
+ * head injection *required* here otherwise quiesce won't work
+ */
+ blk_execute_rq(req->q, NULL, req, 1);
+
+ /*
+ * Some devices (USB mass-storage in particular) may transfer
+ * garbage data together with a residue indicating that the data
+ * is invalid. Prevent the garbage from being misinterpreted
+ * and prevent security leaks by zeroing out the excess data.
+ */
+ if (unlikely(rq->resid_len > 0 && rq->resid_len <= bufflen))
+ memset(buffer + (bufflen - rq->resid_len), 0, rq->resid_len);
+
+ if (resid)
+ *resid = rq->resid_len;
+ if (sense && rq->sense_len)
+ memcpy(sense, rq->sense, SCSI_SENSE_BUFFERSIZE);
+ if (sshdr)
+ scsi_normalize_sense(rq->sense, rq->sense_len, sshdr);
+ ret = rq->result;
+ out:
+ blk_put_request(req);
+
+ return ret;
+}
+EXPORT_SYMBOL(__scsi_execute);
+
+/*
+ * Function: scsi_init_cmd_errh()
+ *
+ * Purpose: Initialize cmd fields related to error handling.
+ *
+ * Arguments: cmd - command that is ready to be queued.
+ *
+ * Notes: This function has the job of initializing a number of
+ * fields related to error handling. Typically this will
+ * be called once for each command, as required.
+ */
+static void scsi_init_cmd_errh(struct scsi_cmnd *cmd)
+{
+ cmd->serial_number = 0;
+ scsi_set_resid(cmd, 0);
+ memset(cmd->sense_buffer, 0, SCSI_SENSE_BUFFERSIZE);
+ if (cmd->cmd_len == 0)
+ cmd->cmd_len = scsi_command_size(cmd->cmnd);
+}
+
+/*
+ * Decrement the host_busy counter and wake up the error handler if necessary.
+ * Avoid as follows that the error handler is not woken up if shost->host_busy
+ * == shost->host_failed: use call_rcu() in scsi_eh_scmd_add() in combination
+ * with an RCU read lock in this function to ensure that this function in its
+ * entirety either finishes before scsi_eh_scmd_add() increases the
+ * host_failed counter or that it notices the shost state change made by
+ * scsi_eh_scmd_add().
+ */
+static void scsi_dec_host_busy(struct Scsi_Host *shost)
+{
+ unsigned long flags;
+
+ rcu_read_lock();
+ atomic_dec(&shost->host_busy);
+ if (unlikely(scsi_host_in_recovery(shost))) {
+ spin_lock_irqsave(shost->host_lock, flags);
+ if (shost->host_failed || shost->host_eh_scheduled)
+ scsi_eh_wakeup(shost);
+ spin_unlock_irqrestore(shost->host_lock, flags);
+ }
+ rcu_read_unlock();
+}
+
+void scsi_device_unbusy(struct scsi_device *sdev)
+{
+ struct Scsi_Host *shost = sdev->host;
+ struct scsi_target *starget = scsi_target(sdev);
+
+ scsi_dec_host_busy(shost);
+
+ if (starget->can_queue > 0)
+ atomic_dec(&starget->target_busy);
+
+ atomic_dec(&sdev->device_busy);
+}
+
+static void scsi_kick_queue(struct request_queue *q)
+{
+ if (q->mq_ops)
+ blk_mq_run_hw_queues(q, false);
+ else
+ blk_run_queue(q);
+}
+
+/*
+ * Called for single_lun devices on IO completion. Clear starget_sdev_user,
+ * and call blk_run_queue for all the scsi_devices on the target -
+ * including current_sdev first.
+ *
+ * Called with *no* scsi locks held.
+ */
+static void scsi_single_lun_run(struct scsi_device *current_sdev)
+{
+ struct Scsi_Host *shost = current_sdev->host;
+ struct scsi_device *sdev, *tmp;
+ struct scsi_target *starget = scsi_target(current_sdev);
+ unsigned long flags;
+
+ spin_lock_irqsave(shost->host_lock, flags);
+ starget->starget_sdev_user = NULL;
+ spin_unlock_irqrestore(shost->host_lock, flags);
+
+ /*
+ * Call blk_run_queue for all LUNs on the target, starting with
+ * current_sdev. We race with others (to set starget_sdev_user),
+ * but in most cases, we will be first. Ideally, each LU on the
+ * target would get some limited time or requests on the target.
+ */
+ scsi_kick_queue(current_sdev->request_queue);
+
+ spin_lock_irqsave(shost->host_lock, flags);
+ if (starget->starget_sdev_user)
+ goto out;
+ list_for_each_entry_safe(sdev, tmp, &starget->devices,
+ same_target_siblings) {
+ if (sdev == current_sdev)
+ continue;
+ if (scsi_device_get(sdev))
+ continue;
+
+ spin_unlock_irqrestore(shost->host_lock, flags);
+ scsi_kick_queue(sdev->request_queue);
+ spin_lock_irqsave(shost->host_lock, flags);
+
+ scsi_device_put(sdev);
+ }
+ out:
+ spin_unlock_irqrestore(shost->host_lock, flags);
+}
+
+static inline bool scsi_device_is_busy(struct scsi_device *sdev)
+{
+ if (atomic_read(&sdev->device_busy) >= sdev->queue_depth)
+ return true;
+ if (atomic_read(&sdev->device_blocked) > 0)
+ return true;
+ return false;
+}
+
+static inline bool scsi_target_is_busy(struct scsi_target *starget)
+{
+ if (starget->can_queue > 0) {
+ if (atomic_read(&starget->target_busy) >= starget->can_queue)
+ return true;
+ if (atomic_read(&starget->target_blocked) > 0)
+ return true;
+ }
+ return false;
+}
+
+static inline bool scsi_host_is_busy(struct Scsi_Host *shost)
+{
+ if (shost->can_queue > 0 &&
+ atomic_read(&shost->host_busy) >= shost->can_queue)
+ return true;
+ if (atomic_read(&shost->host_blocked) > 0)
+ return true;
+ if (shost->host_self_blocked)
+ return true;
+ return false;
+}
+
+static void scsi_starved_list_run(struct Scsi_Host *shost)
+{
+ LIST_HEAD(starved_list);
+ struct scsi_device *sdev;
+ unsigned long flags;
+
+ spin_lock_irqsave(shost->host_lock, flags);
+ list_splice_init(&shost->starved_list, &starved_list);
+
+ while (!list_empty(&starved_list)) {
+ struct request_queue *slq;
+
+ /*
+ * As long as shost is accepting commands and we have
+ * starved queues, call blk_run_queue. scsi_request_fn
+ * drops the queue_lock and can add us back to the
+ * starved_list.
+ *
+ * host_lock protects the starved_list and starved_entry.
+ * scsi_request_fn must get the host_lock before checking
+ * or modifying starved_list or starved_entry.
+ */
+ if (scsi_host_is_busy(shost))
+ break;
+
+ sdev = list_entry(starved_list.next,
+ struct scsi_device, starved_entry);
+ list_del_init(&sdev->starved_entry);
+ if (scsi_target_is_busy(scsi_target(sdev))) {
+ list_move_tail(&sdev->starved_entry,
+ &shost->starved_list);
+ continue;
+ }
+
+ /*
+ * Once we drop the host lock, a racing scsi_remove_device()
+ * call may remove the sdev from the starved list and destroy
+ * it and the queue. Mitigate by taking a reference to the
+ * queue and never touching the sdev again after we drop the
+ * host lock. Note: if __scsi_remove_device() invokes
+ * blk_cleanup_queue() before the queue is run from this
+ * function then blk_run_queue() will return immediately since
+ * blk_cleanup_queue() marks the queue with QUEUE_FLAG_DYING.
+ */
+ slq = sdev->request_queue;
+ if (!blk_get_queue(slq))
+ continue;
+ spin_unlock_irqrestore(shost->host_lock, flags);
+
+ scsi_kick_queue(slq);
+ blk_put_queue(slq);
+
+ spin_lock_irqsave(shost->host_lock, flags);
+ }
+ /* put any unprocessed entries back */
+ list_splice(&starved_list, &shost->starved_list);
+ spin_unlock_irqrestore(shost->host_lock, flags);
+}
+
+/*
+ * Function: scsi_run_queue()
+ *
+ * Purpose: Select a proper request queue to serve next
+ *
+ * Arguments: q - last request's queue
+ *
+ * Returns: Nothing
+ *
+ * Notes: The previous command was completely finished, start
+ * a new one if possible.
+ */
+static void scsi_run_queue(struct request_queue *q)
+{
+ struct scsi_device *sdev = q->queuedata;
+
+ if (scsi_target(sdev)->single_lun)
+ scsi_single_lun_run(sdev);
+ if (!list_empty(&sdev->host->starved_list))
+ scsi_starved_list_run(sdev->host);
+
+ if (q->mq_ops)
+ blk_mq_run_hw_queues(q, false);
+ else
+ blk_run_queue(q);
+}
+
+void scsi_requeue_run_queue(struct work_struct *work)
+{
+ struct scsi_device *sdev;
+ struct request_queue *q;
+
+ sdev = container_of(work, struct scsi_device, requeue_work);
+ q = sdev->request_queue;
+ scsi_run_queue(q);
+}
+
+/*
+ * Function: scsi_requeue_command()
+ *
+ * Purpose: Handle post-processing of completed commands.
+ *
+ * Arguments: q - queue to operate on
+ * cmd - command that may need to be requeued.
+ *
+ * Returns: Nothing
+ *
+ * Notes: After command completion, there may be blocks left
+ * over which weren't finished by the previous command
+ * this can be for a number of reasons - the main one is
+ * I/O errors in the middle of the request, in which case
+ * we need to request the blocks that come after the bad
+ * sector.
+ * Notes: Upon return, cmd is a stale pointer.
+ */
+static void scsi_requeue_command(struct request_queue *q, struct scsi_cmnd *cmd)
+{
+ struct scsi_device *sdev = cmd->device;
+ struct request *req = cmd->request;
+ unsigned long flags;
+
+ spin_lock_irqsave(q->queue_lock, flags);
+ blk_unprep_request(req);
+ req->special = NULL;
+ scsi_put_command(cmd);
+ blk_requeue_request(q, req);
+ spin_unlock_irqrestore(q->queue_lock, flags);
+
+ scsi_run_queue(q);
+
+ put_device(&sdev->sdev_gendev);
+}
+
+void scsi_run_host_queues(struct Scsi_Host *shost)
+{
+ struct scsi_device *sdev;
+
+ shost_for_each_device(sdev, shost)
+ scsi_run_queue(sdev->request_queue);
+}
+
+static void scsi_uninit_cmd(struct scsi_cmnd *cmd)
+{
+ if (!blk_rq_is_passthrough(cmd->request)) {
+ struct scsi_driver *drv = scsi_cmd_to_driver(cmd);
+
+ if (drv->uninit_command)
+ drv->uninit_command(cmd);
+ }
+}
+
+static void scsi_mq_free_sgtables(struct scsi_cmnd *cmd)
+{
+ struct scsi_data_buffer *sdb;
+
+ if (cmd->sdb.table.nents)
+ sg_free_table_chained(&cmd->sdb.table, true);
+ if (cmd->request->next_rq) {
+ sdb = cmd->request->next_rq->special;
+ if (sdb)
+ sg_free_table_chained(&sdb->table, true);
+ }
+ if (scsi_prot_sg_count(cmd))
+ sg_free_table_chained(&cmd->prot_sdb->table, true);
+}
+
+static void scsi_mq_uninit_cmd(struct scsi_cmnd *cmd)
+{
+ scsi_mq_free_sgtables(cmd);
+ scsi_uninit_cmd(cmd);
+ scsi_del_cmd_from_list(cmd);
+}
+
+/*
+ * Function: scsi_release_buffers()
+ *
+ * Purpose: Free resources allocate for a scsi_command.
+ *
+ * Arguments: cmd - command that we are bailing.
+ *
+ * Lock status: Assumed that no lock is held upon entry.
+ *
+ * Returns: Nothing
+ *
+ * Notes: In the event that an upper level driver rejects a
+ * command, we must release resources allocated during
+ * the __init_io() function. Primarily this would involve
+ * the scatter-gather table.
+ */
+static void scsi_release_buffers(struct scsi_cmnd *cmd)
+{
+ if (cmd->sdb.table.nents)
+ sg_free_table_chained(&cmd->sdb.table, false);
+
+ memset(&cmd->sdb, 0, sizeof(cmd->sdb));
+
+ if (scsi_prot_sg_count(cmd))
+ sg_free_table_chained(&cmd->prot_sdb->table, false);
+}
+
+static void scsi_release_bidi_buffers(struct scsi_cmnd *cmd)
+{
+ struct scsi_data_buffer *bidi_sdb = cmd->request->next_rq->special;
+
+ sg_free_table_chained(&bidi_sdb->table, false);
+ kmem_cache_free(scsi_sdb_cache, bidi_sdb);
+ cmd->request->next_rq->special = NULL;
+}
+
+/* Returns false when no more bytes to process, true if there are more */
+static bool scsi_end_request(struct request *req, blk_status_t error,
+ unsigned int bytes, unsigned int bidi_bytes)
+{
+ struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(req);
+ struct scsi_device *sdev = cmd->device;
+ struct request_queue *q = sdev->request_queue;
+
+ if (blk_update_request(req, error, bytes))
+ return true;
+
+ /* Bidi request must be completed as a whole */
+ if (unlikely(bidi_bytes) &&
+ blk_update_request(req->next_rq, error, bidi_bytes))
+ return true;
+
+ if (blk_queue_add_random(q))
+ add_disk_randomness(req->rq_disk);
+
+ if (!blk_rq_is_scsi(req)) {
+ WARN_ON_ONCE(!(cmd->flags & SCMD_INITIALIZED));
+ cmd->flags &= ~SCMD_INITIALIZED;
+ destroy_rcu_head(&cmd->rcu);
+ }
+
+ if (req->mq_ctx) {
+ /*
+ * In the MQ case the command gets freed by __blk_mq_end_request,
+ * so we have to do all cleanup that depends on it earlier.
+ *
+ * We also can't kick the queues from irq context, so we
+ * will have to defer it to a workqueue.
+ */
+ scsi_mq_uninit_cmd(cmd);
+
+ /*
+ * queue is still alive, so grab the ref for preventing it
+ * from being cleaned up during running queue.
+ */
+ percpu_ref_get(&q->q_usage_counter);
+
+ __blk_mq_end_request(req, error);
+
+ if (scsi_target(sdev)->single_lun ||
+ !list_empty(&sdev->host->starved_list))
+ kblockd_schedule_work(&sdev->requeue_work);
+ else
+ blk_mq_run_hw_queues(q, true);
+
+ percpu_ref_put(&q->q_usage_counter);
+ } else {
+ unsigned long flags;
+
+ if (bidi_bytes)
+ scsi_release_bidi_buffers(cmd);
+ scsi_release_buffers(cmd);
+ scsi_put_command(cmd);
+
+ spin_lock_irqsave(q->queue_lock, flags);
+ blk_finish_request(req, error);
+ spin_unlock_irqrestore(q->queue_lock, flags);
+
+ scsi_run_queue(q);
+ }
+
+ put_device(&sdev->sdev_gendev);
+ return false;
+}
+
+/**
+ * scsi_result_to_blk_status - translate a SCSI result code into blk_status_t
+ * @cmd: SCSI command
+ * @result: scsi error code
+ *
+ * Translate a SCSI result code into a blk_status_t value. May reset the host
+ * byte of @cmd->result.
+ */
+static blk_status_t scsi_result_to_blk_status(struct scsi_cmnd *cmd, int result)
+{
+ switch (host_byte(result)) {
+ case DID_OK:
+ /*
+ * Also check the other bytes than the status byte in result
+ * to handle the case when a SCSI LLD sets result to
+ * DRIVER_SENSE << 24 without setting SAM_STAT_CHECK_CONDITION.
+ */
+ if (scsi_status_is_good(result) && (result & ~0xff) == 0)
+ return BLK_STS_OK;
+ return BLK_STS_IOERR;
+ case DID_TRANSPORT_FAILFAST:
+ return BLK_STS_TRANSPORT;
+ case DID_TARGET_FAILURE:
+ set_host_byte(cmd, DID_OK);
+ return BLK_STS_TARGET;
+ case DID_NEXUS_FAILURE:
+ return BLK_STS_NEXUS;
+ case DID_ALLOC_FAILURE:
+ set_host_byte(cmd, DID_OK);
+ return BLK_STS_NOSPC;
+ case DID_MEDIUM_ERROR:
+ set_host_byte(cmd, DID_OK);
+ return BLK_STS_MEDIUM;
+ default:
+ return BLK_STS_IOERR;
+ }
+}
+
+/* Helper for scsi_io_completion() when "reprep" action required. */
+static void scsi_io_completion_reprep(struct scsi_cmnd *cmd,
+ struct request_queue *q)
+{
+ /* A new command will be prepared and issued. */
+ if (q->mq_ops) {
+ scsi_mq_requeue_cmd(cmd);
+ } else {
+ /* Unprep request and put it back at head of the queue. */
+ scsi_release_buffers(cmd);
+ scsi_requeue_command(q, cmd);
+ }
+}
+
+/* Helper for scsi_io_completion() when special action required. */
+static void scsi_io_completion_action(struct scsi_cmnd *cmd, int result)
+{
+ struct request_queue *q = cmd->device->request_queue;
+ struct request *req = cmd->request;
+ int level = 0;
+ enum {ACTION_FAIL, ACTION_REPREP, ACTION_RETRY,
+ ACTION_DELAYED_RETRY} action;
+ unsigned long wait_for = (cmd->allowed + 1) * req->timeout;
+ struct scsi_sense_hdr sshdr;
+ bool sense_valid;
+ bool sense_current = true; /* false implies "deferred sense" */
+ blk_status_t blk_stat;
+
+ sense_valid = scsi_command_normalize_sense(cmd, &sshdr);
+ if (sense_valid)
+ sense_current = !scsi_sense_is_deferred(&sshdr);
+
+ blk_stat = scsi_result_to_blk_status(cmd, result);
+
+ if (host_byte(result) == DID_RESET) {
+ /* Third party bus reset or reset for error recovery
+ * reasons. Just retry the command and see what
+ * happens.
+ */
+ action = ACTION_RETRY;
+ } else if (sense_valid && sense_current) {
+ switch (sshdr.sense_key) {
+ case UNIT_ATTENTION:
+ if (cmd->device->removable) {
+ /* Detected disc change. Set a bit
+ * and quietly refuse further access.
+ */
+ cmd->device->changed = 1;
+ action = ACTION_FAIL;
+ } else {
+ /* Must have been a power glitch, or a
+ * bus reset. Could not have been a
+ * media change, so we just retry the
+ * command and see what happens.
+ */
+ action = ACTION_RETRY;
+ }
+ break;
+ case ILLEGAL_REQUEST:
+ /* If we had an ILLEGAL REQUEST returned, then
+ * we may have performed an unsupported
+ * command. The only thing this should be
+ * would be a ten byte read where only a six
+ * byte read was supported. Also, on a system
+ * where READ CAPACITY failed, we may have
+ * read past the end of the disk.
+ */
+ if ((cmd->device->use_10_for_rw &&
+ sshdr.asc == 0x20 && sshdr.ascq == 0x00) &&
+ (cmd->cmnd[0] == READ_10 ||
+ cmd->cmnd[0] == WRITE_10)) {
+ /* This will issue a new 6-byte command. */
+ cmd->device->use_10_for_rw = 0;
+ action = ACTION_REPREP;
+ } else if (sshdr.asc == 0x10) /* DIX */ {
+ action = ACTION_FAIL;
+ blk_stat = BLK_STS_PROTECTION;
+ /* INVALID COMMAND OPCODE or INVALID FIELD IN CDB */
+ } else if (sshdr.asc == 0x20 || sshdr.asc == 0x24) {
+ action = ACTION_FAIL;
+ blk_stat = BLK_STS_TARGET;
+ } else
+ action = ACTION_FAIL;
+ break;
+ case ABORTED_COMMAND:
+ action = ACTION_FAIL;
+ if (sshdr.asc == 0x10) /* DIF */
+ blk_stat = BLK_STS_PROTECTION;
+ break;
+ case NOT_READY:
+ /* If the device is in the process of becoming
+ * ready, or has a temporary blockage, retry.
+ */
+ if (sshdr.asc == 0x04) {
+ switch (sshdr.ascq) {
+ case 0x01: /* becoming ready */
+ case 0x04: /* format in progress */
+ case 0x05: /* rebuild in progress */
+ case 0x06: /* recalculation in progress */
+ case 0x07: /* operation in progress */
+ case 0x08: /* Long write in progress */
+ case 0x09: /* self test in progress */
+ case 0x14: /* space allocation in progress */
+ case 0x1a: /* start stop unit in progress */
+ case 0x1b: /* sanitize in progress */
+ case 0x1d: /* configuration in progress */
+ case 0x24: /* depopulation in progress */
+ action = ACTION_DELAYED_RETRY;
+ break;
+ default:
+ action = ACTION_FAIL;
+ break;
+ }
+ } else
+ action = ACTION_FAIL;
+ break;
+ case VOLUME_OVERFLOW:
+ /* See SSC3rXX or current. */
+ action = ACTION_FAIL;
+ break;
+ default:
+ action = ACTION_FAIL;
+ break;
+ }
+ } else
+ action = ACTION_FAIL;
+
+ if (action != ACTION_FAIL &&
+ time_before(cmd->jiffies_at_alloc + wait_for, jiffies))
+ action = ACTION_FAIL;
+
+ switch (action) {
+ case ACTION_FAIL:
+ /* Give up and fail the remainder of the request */
+ if (!(req->rq_flags & RQF_QUIET)) {
+ static DEFINE_RATELIMIT_STATE(_rs,
+ DEFAULT_RATELIMIT_INTERVAL,
+ DEFAULT_RATELIMIT_BURST);
+
+ if (unlikely(scsi_logging_level))
+ level =
+ SCSI_LOG_LEVEL(SCSI_LOG_MLCOMPLETE_SHIFT,
+ SCSI_LOG_MLCOMPLETE_BITS);
+
+ /*
+ * if logging is enabled the failure will be printed
+ * in scsi_log_completion(), so avoid duplicate messages
+ */
+ if (!level && __ratelimit(&_rs)) {
+ scsi_print_result(cmd, NULL, FAILED);
+ if (driver_byte(result) == DRIVER_SENSE)
+ scsi_print_sense(cmd);
+ scsi_print_command(cmd);
+ }
+ }
+ if (!scsi_end_request(req, blk_stat, blk_rq_err_bytes(req), 0))
+ return;
+ /*FALLTHRU*/
+ case ACTION_REPREP:
+ scsi_io_completion_reprep(cmd, q);
+ break;
+ case ACTION_RETRY:
+ /* Retry the same command immediately */
+ __scsi_queue_insert(cmd, SCSI_MLQUEUE_EH_RETRY, false);
+ break;
+ case ACTION_DELAYED_RETRY:
+ /* Retry the same command after a delay */
+ __scsi_queue_insert(cmd, SCSI_MLQUEUE_DEVICE_BUSY, false);
+ break;
+ }
+}
+
+/*
+ * Helper for scsi_io_completion() when cmd->result is non-zero. Returns a
+ * new result that may suppress further error checking. Also modifies
+ * *blk_statp in some cases.
+ */
+static int scsi_io_completion_nz_result(struct scsi_cmnd *cmd, int result,
+ blk_status_t *blk_statp)
+{
+ bool sense_valid;
+ bool sense_current = true; /* false implies "deferred sense" */
+ struct request *req = cmd->request;
+ struct scsi_sense_hdr sshdr;
+
+ sense_valid = scsi_command_normalize_sense(cmd, &sshdr);
+ if (sense_valid)
+ sense_current = !scsi_sense_is_deferred(&sshdr);
+
+ if (blk_rq_is_passthrough(req)) {
+ if (sense_valid) {
+ /*
+ * SG_IO wants current and deferred errors
+ */
+ scsi_req(req)->sense_len =
+ min(8 + cmd->sense_buffer[7],
+ SCSI_SENSE_BUFFERSIZE);
+ }
+ if (sense_current)
+ *blk_statp = scsi_result_to_blk_status(cmd, result);
+ } else if (blk_rq_bytes(req) == 0 && sense_current) {
+ /*
+ * Flush commands do not transfers any data, and thus cannot use
+ * good_bytes != blk_rq_bytes(req) as the signal for an error.
+ * This sets *blk_statp explicitly for the problem case.
+ */
+ *blk_statp = scsi_result_to_blk_status(cmd, result);
+ }
+ /*
+ * Recovered errors need reporting, but they're always treated as
+ * success, so fiddle the result code here. For passthrough requests
+ * we already took a copy of the original into sreq->result which
+ * is what gets returned to the user
+ */
+ if (sense_valid && (sshdr.sense_key == RECOVERED_ERROR)) {
+ bool do_print = true;
+ /*
+ * if ATA PASS-THROUGH INFORMATION AVAILABLE [0x0, 0x1d]
+ * skip print since caller wants ATA registers. Only occurs
+ * on SCSI ATA PASS_THROUGH commands when CK_COND=1
+ */
+ if ((sshdr.asc == 0x0) && (sshdr.ascq == 0x1d))
+ do_print = false;
+ else if (req->rq_flags & RQF_QUIET)
+ do_print = false;
+ if (do_print)
+ scsi_print_sense(cmd);
+ result = 0;
+ /* for passthrough, *blk_statp may be set */
+ *blk_statp = BLK_STS_OK;
+ }
+ /*
+ * Another corner case: the SCSI status byte is non-zero but 'good'.
+ * Example: PRE-FETCH command returns SAM_STAT_CONDITION_MET when
+ * it is able to fit nominated LBs in its cache (and SAM_STAT_GOOD
+ * if it can't fit). Treat SAM_STAT_CONDITION_MET and the related
+ * intermediate statuses (both obsolete in SAM-4) as good.
+ */
+ if (status_byte(result) && scsi_status_is_good(result)) {
+ result = 0;
+ *blk_statp = BLK_STS_OK;
+ }
+ return result;
+}
+
+/*
+ * Function: scsi_io_completion()
+ *
+ * Purpose: Completion processing for block device I/O requests.
+ *
+ * Arguments: cmd - command that is finished.
+ *
+ * Lock status: Assumed that no lock is held upon entry.
+ *
+ * Returns: Nothing
+ *
+ * Notes: We will finish off the specified number of sectors. If we
+ * are done, the command block will be released and the queue
+ * function will be goosed. If we are not done then we have to
+ * figure out what to do next:
+ *
+ * a) We can call scsi_requeue_command(). The request
+ * will be unprepared and put back on the queue. Then
+ * a new command will be created for it. This should
+ * be used if we made forward progress, or if we want
+ * to switch from READ(10) to READ(6) for example.
+ *
+ * b) We can call __scsi_queue_insert(). The request will
+ * be put back on the queue and retried using the same
+ * command as before, possibly after a delay.
+ *
+ * c) We can call scsi_end_request() with blk_stat other than
+ * BLK_STS_OK, to fail the remainder of the request.
+ */
+void scsi_io_completion(struct scsi_cmnd *cmd, unsigned int good_bytes)
+{
+ int result = cmd->result;
+ struct request_queue *q = cmd->device->request_queue;
+ struct request *req = cmd->request;
+ blk_status_t blk_stat = BLK_STS_OK;
+
+ if (unlikely(result)) /* a nz result may or may not be an error */
+ result = scsi_io_completion_nz_result(cmd, result, &blk_stat);
+
+ if (unlikely(blk_rq_is_passthrough(req))) {
+ /*
+ * scsi_result_to_blk_status may have reset the host_byte
+ */
+ scsi_req(req)->result = cmd->result;
+ scsi_req(req)->resid_len = scsi_get_resid(cmd);
+
+ if (unlikely(scsi_bidi_cmnd(cmd))) {
+ /*
+ * Bidi commands Must be complete as a whole,
+ * both sides at once.
+ */
+ scsi_req(req->next_rq)->resid_len = scsi_in(cmd)->resid;
+ if (scsi_end_request(req, BLK_STS_OK, blk_rq_bytes(req),
+ blk_rq_bytes(req->next_rq)))
+ WARN_ONCE(true,
+ "Bidi command with remaining bytes");
+ return;
+ }
+ }
+
+ /* no bidi support yet, other than in pass-through */
+ if (unlikely(blk_bidi_rq(req))) {
+ WARN_ONCE(true, "Only support bidi command in passthrough");
+ scmd_printk(KERN_ERR, cmd, "Killing bidi command\n");
+ if (scsi_end_request(req, BLK_STS_IOERR, blk_rq_bytes(req),
+ blk_rq_bytes(req->next_rq)))
+ WARN_ONCE(true, "Bidi command with remaining bytes");
+ return;
+ }
+
+ /*
+ * Next deal with any sectors which we were able to correctly
+ * handle.
+ */
+ SCSI_LOG_HLCOMPLETE(1, scmd_printk(KERN_INFO, cmd,
+ "%u sectors total, %d bytes done.\n",
+ blk_rq_sectors(req), good_bytes));
+
+ /*
+ * Next deal with any sectors which we were able to correctly
+ * handle. Failed, zero length commands always need to drop down
+ * to retry code. Fast path should return in this block.
+ */
+ if (likely(blk_rq_bytes(req) > 0 || blk_stat == BLK_STS_OK)) {
+ if (likely(!scsi_end_request(req, blk_stat, good_bytes, 0)))
+ return; /* no bytes remaining */
+ }
+
+ /* Kill remainder if no retries. */
+ if (unlikely(blk_stat && scsi_noretry_cmd(cmd))) {
+ if (scsi_end_request(req, blk_stat, blk_rq_bytes(req), 0))
+ WARN_ONCE(true,
+ "Bytes remaining after failed, no-retry command");
+ return;
+ }
+
+ /*
+ * If there had been no error, but we have leftover bytes in the
+ * requeues just queue the command up again.
+ */
+ if (likely(result == 0))
+ scsi_io_completion_reprep(cmd, q);
+ else
+ scsi_io_completion_action(cmd, result);
+}
+
+static int scsi_init_sgtable(struct request *req, struct scsi_data_buffer *sdb)
+{
+ int count;
+
+ /*
+ * If sg table allocation fails, requeue request later.
+ */
+ if (unlikely(sg_alloc_table_chained(&sdb->table,
+ blk_rq_nr_phys_segments(req), sdb->table.sgl)))
+ return BLKPREP_DEFER;
+
+ /*
+ * Next, walk the list, and fill in the addresses and sizes of
+ * each segment.
+ */
+ count = blk_rq_map_sg(req->q, req, sdb->table.sgl);
+ BUG_ON(count > sdb->table.nents);
+ sdb->table.nents = count;
+ sdb->length = blk_rq_payload_bytes(req);
+ return BLKPREP_OK;
+}
+
+/*
+ * Function: scsi_init_io()
+ *
+ * Purpose: SCSI I/O initialize function.
+ *
+ * Arguments: cmd - Command descriptor we wish to initialize
+ *
+ * Returns: 0 on success
+ * BLKPREP_DEFER if the failure is retryable
+ * BLKPREP_KILL if the failure is fatal
+ */
+int scsi_init_io(struct scsi_cmnd *cmd)
+{
+ struct scsi_device *sdev = cmd->device;
+ struct request *rq = cmd->request;
+ bool is_mq = (rq->mq_ctx != NULL);
+ int error = BLKPREP_KILL;
+
+ if (WARN_ON_ONCE(!blk_rq_nr_phys_segments(rq)))
+ goto err_exit;
+
+ error = scsi_init_sgtable(rq, &cmd->sdb);
+ if (error)
+ goto err_exit;
+
+ if (blk_bidi_rq(rq)) {
+ if (!rq->q->mq_ops) {
+ struct scsi_data_buffer *bidi_sdb =
+ kmem_cache_zalloc(scsi_sdb_cache, GFP_ATOMIC);
+ if (!bidi_sdb) {
+ error = BLKPREP_DEFER;
+ goto err_exit;
+ }
+
+ rq->next_rq->special = bidi_sdb;
+ }
+
+ error = scsi_init_sgtable(rq->next_rq, rq->next_rq->special);
+ if (error)
+ goto err_exit;
+ }
+
+ if (blk_integrity_rq(rq)) {
+ struct scsi_data_buffer *prot_sdb = cmd->prot_sdb;
+ int ivecs, count;
+
+ if (prot_sdb == NULL) {
+ /*
+ * This can happen if someone (e.g. multipath)
+ * queues a command to a device on an adapter
+ * that does not support DIX.
+ */
+ WARN_ON_ONCE(1);
+ error = BLKPREP_KILL;
+ goto err_exit;
+ }
+
+ ivecs = blk_rq_count_integrity_sg(rq->q, rq->bio);
+
+ if (sg_alloc_table_chained(&prot_sdb->table, ivecs,
+ prot_sdb->table.sgl)) {
+ error = BLKPREP_DEFER;
+ goto err_exit;
+ }
+
+ count = blk_rq_map_integrity_sg(rq->q, rq->bio,
+ prot_sdb->table.sgl);
+ BUG_ON(unlikely(count > ivecs));
+ BUG_ON(unlikely(count > queue_max_integrity_segments(rq->q)));
+
+ cmd->prot_sdb = prot_sdb;
+ cmd->prot_sdb->table.nents = count;
+ }
+
+ return BLKPREP_OK;
+err_exit:
+ if (is_mq) {
+ scsi_mq_free_sgtables(cmd);
+ } else {
+ scsi_release_buffers(cmd);
+ cmd->request->special = NULL;
+ scsi_put_command(cmd);
+ put_device(&sdev->sdev_gendev);
+ }
+ return error;
+}
+EXPORT_SYMBOL(scsi_init_io);
+
+/**
+ * scsi_initialize_rq - initialize struct scsi_cmnd partially
+ * @rq: Request associated with the SCSI command to be initialized.
+ *
+ * This function initializes the members of struct scsi_cmnd that must be
+ * initialized before request processing starts and that won't be
+ * reinitialized if a SCSI command is requeued.
+ *
+ * Called from inside blk_get_request() for pass-through requests and from
+ * inside scsi_init_command() for filesystem requests.
+ */
+static void scsi_initialize_rq(struct request *rq)
+{
+ struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(rq);
+
+ scsi_req_init(&cmd->req);
+ init_rcu_head(&cmd->rcu);
+ cmd->jiffies_at_alloc = jiffies;
+ cmd->retries = 0;
+}
+
+/* Add a command to the list used by the aacraid and dpt_i2o drivers */
+void scsi_add_cmd_to_list(struct scsi_cmnd *cmd)
+{
+ struct scsi_device *sdev = cmd->device;
+ struct Scsi_Host *shost = sdev->host;
+ unsigned long flags;
+
+ if (shost->use_cmd_list) {
+ spin_lock_irqsave(&sdev->list_lock, flags);
+ list_add_tail(&cmd->list, &sdev->cmd_list);
+ spin_unlock_irqrestore(&sdev->list_lock, flags);
+ }
+}
+
+/* Remove a command from the list used by the aacraid and dpt_i2o drivers */
+void scsi_del_cmd_from_list(struct scsi_cmnd *cmd)
+{
+ struct scsi_device *sdev = cmd->device;
+ struct Scsi_Host *shost = sdev->host;
+ unsigned long flags;
+
+ if (shost->use_cmd_list) {
+ spin_lock_irqsave(&sdev->list_lock, flags);
+ BUG_ON(list_empty(&cmd->list));
+ list_del_init(&cmd->list);
+ spin_unlock_irqrestore(&sdev->list_lock, flags);
+ }
+}
+
+/* Called after a request has been started. */
+void scsi_init_command(struct scsi_device *dev, struct scsi_cmnd *cmd)
+{
+ void *buf = cmd->sense_buffer;
+ void *prot = cmd->prot_sdb;
+ struct request *rq = blk_mq_rq_from_pdu(cmd);
+ unsigned int flags = cmd->flags & SCMD_PRESERVED_FLAGS;
+ unsigned long jiffies_at_alloc;
+ int retries;
+
+ if (!blk_rq_is_scsi(rq) && !(flags & SCMD_INITIALIZED)) {
+ flags |= SCMD_INITIALIZED;
+ scsi_initialize_rq(rq);
+ }
+
+ jiffies_at_alloc = cmd->jiffies_at_alloc;
+ retries = cmd->retries;
+ /* zero out the cmd, except for the embedded scsi_request */
+ memset((char *)cmd + sizeof(cmd->req), 0,
+ sizeof(*cmd) - sizeof(cmd->req) + dev->host->hostt->cmd_size);
+
+ cmd->device = dev;
+ cmd->sense_buffer = buf;
+ cmd->prot_sdb = prot;
+ cmd->flags = flags;
+ INIT_DELAYED_WORK(&cmd->abort_work, scmd_eh_abort_handler);
+ cmd->jiffies_at_alloc = jiffies_at_alloc;
+ cmd->retries = retries;
+
+ scsi_add_cmd_to_list(cmd);
+}
+
+static int scsi_setup_scsi_cmnd(struct scsi_device *sdev, struct request *req)
+{
+ struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(req);
+
+ /*
+ * Passthrough requests may transfer data, in which case they must
+ * a bio attached to them. Or they might contain a SCSI command
+ * that does not transfer data, in which case they may optionally
+ * submit a request without an attached bio.
+ */
+ if (req->bio) {
+ int ret = scsi_init_io(cmd);
+ if (unlikely(ret))
+ return ret;
+ } else {
+ BUG_ON(blk_rq_bytes(req));
+
+ memset(&cmd->sdb, 0, sizeof(cmd->sdb));
+ }
+
+ cmd->cmd_len = scsi_req(req)->cmd_len;
+ cmd->cmnd = scsi_req(req)->cmd;
+ cmd->transfersize = blk_rq_bytes(req);
+ cmd->allowed = scsi_req(req)->retries;
+ return BLKPREP_OK;
+}
+
+/*
+ * Setup a normal block command. These are simple request from filesystems
+ * that still need to be translated to SCSI CDBs from the ULD.
+ */
+static int scsi_setup_fs_cmnd(struct scsi_device *sdev, struct request *req)
+{
+ struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(req);
+
+ if (unlikely(sdev->handler && sdev->handler->prep_fn)) {
+ int ret = sdev->handler->prep_fn(sdev, req);
+ if (ret != BLKPREP_OK)
+ return ret;
+ }
+
+ cmd->cmnd = scsi_req(req)->cmd = scsi_req(req)->__cmd;
+ memset(cmd->cmnd, 0, BLK_MAX_CDB);
+ return scsi_cmd_to_driver(cmd)->init_command(cmd);
+}
+
+static int scsi_setup_cmnd(struct scsi_device *sdev, struct request *req)
+{
+ struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(req);
+
+ if (!blk_rq_bytes(req))
+ cmd->sc_data_direction = DMA_NONE;
+ else if (rq_data_dir(req) == WRITE)
+ cmd->sc_data_direction = DMA_TO_DEVICE;
+ else
+ cmd->sc_data_direction = DMA_FROM_DEVICE;
+
+ if (blk_rq_is_scsi(req))
+ return scsi_setup_scsi_cmnd(sdev, req);
+ else
+ return scsi_setup_fs_cmnd(sdev, req);
+}
+
+static int
+scsi_prep_state_check(struct scsi_device *sdev, struct request *req)
+{
+ int ret = BLKPREP_OK;
+
+ /*
+ * If the device is not in running state we will reject some
+ * or all commands.
+ */
+ if (unlikely(sdev->sdev_state != SDEV_RUNNING)) {
+ switch (sdev->sdev_state) {
+ case SDEV_OFFLINE:
+ case SDEV_TRANSPORT_OFFLINE:
+ /*
+ * If the device is offline we refuse to process any
+ * commands. The device must be brought online
+ * before trying any recovery commands.
+ */
+ sdev_printk(KERN_ERR, sdev,
+ "rejecting I/O to offline device\n");
+ ret = BLKPREP_KILL;
+ break;
+ case SDEV_DEL:
+ /*
+ * If the device is fully deleted, we refuse to
+ * process any commands as well.
+ */
+ sdev_printk(KERN_ERR, sdev,
+ "rejecting I/O to dead device\n");
+ ret = BLKPREP_KILL;
+ break;
+ case SDEV_BLOCK:
+ case SDEV_CREATED_BLOCK:
+ ret = BLKPREP_DEFER;
+ break;
+ case SDEV_QUIESCE:
+ /*
+ * If the devices is blocked we defer normal commands.
+ */
+ if (req && !(req->rq_flags & RQF_PREEMPT))
+ ret = BLKPREP_DEFER;
+ break;
+ default:
+ /*
+ * For any other not fully online state we only allow
+ * special commands. In particular any user initiated
+ * command is not allowed.
+ */
+ if (req && !(req->rq_flags & RQF_PREEMPT))
+ ret = BLKPREP_KILL;
+ break;
+ }
+ }
+ return ret;
+}
+
+static int
+scsi_prep_return(struct request_queue *q, struct request *req, int ret)
+{
+ struct scsi_device *sdev = q->queuedata;
+
+ switch (ret) {
+ case BLKPREP_KILL:
+ case BLKPREP_INVALID:
+ scsi_req(req)->result = DID_NO_CONNECT << 16;
+ /* release the command and kill it */
+ if (req->special) {
+ struct scsi_cmnd *cmd = req->special;
+ scsi_release_buffers(cmd);
+ scsi_put_command(cmd);
+ put_device(&sdev->sdev_gendev);
+ req->special = NULL;
+ }
+ break;
+ case BLKPREP_DEFER:
+ /*
+ * If we defer, the blk_peek_request() returns NULL, but the
+ * queue must be restarted, so we schedule a callback to happen
+ * shortly.
+ */
+ if (atomic_read(&sdev->device_busy) == 0)
+ blk_delay_queue(q, SCSI_QUEUE_DELAY);
+ break;
+ default:
+ req->rq_flags |= RQF_DONTPREP;
+ }
+
+ return ret;
+}
+
+static int scsi_prep_fn(struct request_queue *q, struct request *req)
+{
+ struct scsi_device *sdev = q->queuedata;
+ struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(req);
+ int ret;
+
+ ret = scsi_prep_state_check(sdev, req);
+ if (ret != BLKPREP_OK)
+ goto out;
+
+ if (!req->special) {
+ /* Bail if we can't get a reference to the device */
+ if (unlikely(!get_device(&sdev->sdev_gendev))) {
+ ret = BLKPREP_DEFER;
+ goto out;
+ }
+
+ scsi_init_command(sdev, cmd);
+ req->special = cmd;
+ }
+
+ cmd->tag = req->tag;
+ cmd->request = req;
+ cmd->prot_op = SCSI_PROT_NORMAL;
+
+ ret = scsi_setup_cmnd(sdev, req);
+out:
+ return scsi_prep_return(q, req, ret);
+}
+
+static void scsi_unprep_fn(struct request_queue *q, struct request *req)
+{
+ scsi_uninit_cmd(blk_mq_rq_to_pdu(req));
+}
+
+/*
+ * scsi_dev_queue_ready: if we can send requests to sdev, return 1 else
+ * return 0.
+ *
+ * Called with the queue_lock held.
+ */
+static inline int scsi_dev_queue_ready(struct request_queue *q,
+ struct scsi_device *sdev)
+{
+ unsigned int busy;
+
+ busy = atomic_inc_return(&sdev->device_busy) - 1;
+ if (atomic_read(&sdev->device_blocked)) {
+ if (busy)
+ goto out_dec;
+
+ /*
+ * unblock after device_blocked iterates to zero
+ */
+ if (atomic_dec_return(&sdev->device_blocked) > 0) {
+ /*
+ * For the MQ case we take care of this in the caller.
+ */
+ if (!q->mq_ops)
+ blk_delay_queue(q, SCSI_QUEUE_DELAY);
+ goto out_dec;
+ }
+ SCSI_LOG_MLQUEUE(3, sdev_printk(KERN_INFO, sdev,
+ "unblocking device at zero depth\n"));
+ }
+
+ if (busy >= sdev->queue_depth)
+ goto out_dec;
+
+ return 1;
+out_dec:
+ atomic_dec(&sdev->device_busy);
+ return 0;
+}
+
+/*
+ * scsi_target_queue_ready: checks if there we can send commands to target
+ * @sdev: scsi device on starget to check.
+ */
+static inline int scsi_target_queue_ready(struct Scsi_Host *shost,
+ struct scsi_device *sdev)
+{
+ struct scsi_target *starget = scsi_target(sdev);
+ unsigned int busy;
+
+ if (starget->single_lun) {
+ spin_lock_irq(shost->host_lock);
+ if (starget->starget_sdev_user &&
+ starget->starget_sdev_user != sdev) {
+ spin_unlock_irq(shost->host_lock);
+ return 0;
+ }
+ starget->starget_sdev_user = sdev;
+ spin_unlock_irq(shost->host_lock);
+ }
+
+ if (starget->can_queue <= 0)
+ return 1;
+
+ busy = atomic_inc_return(&starget->target_busy) - 1;
+ if (atomic_read(&starget->target_blocked) > 0) {
+ if (busy)
+ goto starved;
+
+ /*
+ * unblock after target_blocked iterates to zero
+ */
+ if (atomic_dec_return(&starget->target_blocked) > 0)
+ goto out_dec;
+
+ SCSI_LOG_MLQUEUE(3, starget_printk(KERN_INFO, starget,
+ "unblocking target at zero depth\n"));
+ }
+
+ if (busy >= starget->can_queue)
+ goto starved;
+
+ return 1;
+
+starved:
+ spin_lock_irq(shost->host_lock);
+ list_move_tail(&sdev->starved_entry, &shost->starved_list);
+ spin_unlock_irq(shost->host_lock);
+out_dec:
+ if (starget->can_queue > 0)
+ atomic_dec(&starget->target_busy);
+ return 0;
+}
+
+/*
+ * scsi_host_queue_ready: if we can send requests to shost, return 1 else
+ * return 0. We must end up running the queue again whenever 0 is
+ * returned, else IO can hang.
+ */
+static inline int scsi_host_queue_ready(struct request_queue *q,
+ struct Scsi_Host *shost,
+ struct scsi_device *sdev)
+{
+ unsigned int busy;
+
+ if (scsi_host_in_recovery(shost))
+ return 0;
+
+ busy = atomic_inc_return(&shost->host_busy) - 1;
+ if (atomic_read(&shost->host_blocked) > 0) {
+ if (busy)
+ goto starved;
+
+ /*
+ * unblock after host_blocked iterates to zero
+ */
+ if (atomic_dec_return(&shost->host_blocked) > 0)
+ goto out_dec;
+
+ SCSI_LOG_MLQUEUE(3,
+ shost_printk(KERN_INFO, shost,
+ "unblocking host at zero depth\n"));
+ }
+
+ if (shost->can_queue > 0 && busy >= shost->can_queue)
+ goto starved;
+ if (shost->host_self_blocked)
+ goto starved;
+
+ /* We're OK to process the command, so we can't be starved */
+ if (!list_empty(&sdev->starved_entry)) {
+ spin_lock_irq(shost->host_lock);
+ if (!list_empty(&sdev->starved_entry))
+ list_del_init(&sdev->starved_entry);
+ spin_unlock_irq(shost->host_lock);
+ }
+
+ return 1;
+
+starved:
+ spin_lock_irq(shost->host_lock);
+ if (list_empty(&sdev->starved_entry))
+ list_add_tail(&sdev->starved_entry, &shost->starved_list);
+ spin_unlock_irq(shost->host_lock);
+out_dec:
+ scsi_dec_host_busy(shost);
+ return 0;
+}
+
+/*
+ * Busy state exporting function for request stacking drivers.
+ *
+ * For efficiency, no lock is taken to check the busy state of
+ * shost/starget/sdev, since the returned value is not guaranteed and
+ * may be changed after request stacking drivers call the function,
+ * regardless of taking lock or not.
+ *
+ * When scsi can't dispatch I/Os anymore and needs to kill I/Os scsi
+ * needs to return 'not busy'. Otherwise, request stacking drivers
+ * may hold requests forever.
+ */
+static int scsi_lld_busy(struct request_queue *q)
+{
+ struct scsi_device *sdev = q->queuedata;
+ struct Scsi_Host *shost;
+
+ if (blk_queue_dying(q))
+ return 0;
+
+ shost = sdev->host;
+
+ /*
+ * Ignore host/starget busy state.
+ * Since block layer does not have a concept of fairness across
+ * multiple queues, congestion of host/starget needs to be handled
+ * in SCSI layer.
+ */
+ if (scsi_host_in_recovery(shost) || scsi_device_is_busy(sdev))
+ return 1;
+
+ return 0;
+}
+
+/*
+ * Kill a request for a dead device
+ */
+static void scsi_kill_request(struct request *req, struct request_queue *q)
+{
+ struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(req);
+ struct scsi_device *sdev;
+ struct scsi_target *starget;
+ struct Scsi_Host *shost;
+
+ blk_start_request(req);
+
+ scmd_printk(KERN_INFO, cmd, "killing request\n");
+
+ sdev = cmd->device;
+ starget = scsi_target(sdev);
+ shost = sdev->host;
+ scsi_init_cmd_errh(cmd);
+ cmd->result = DID_NO_CONNECT << 16;
+ atomic_inc(&cmd->device->iorequest_cnt);
+
+ /*
+ * SCSI request completion path will do scsi_device_unbusy(),
+ * bump busy counts. To bump the counters, we need to dance
+ * with the locks as normal issue path does.
+ */
+ atomic_inc(&sdev->device_busy);
+ atomic_inc(&shost->host_busy);
+ if (starget->can_queue > 0)
+ atomic_inc(&starget->target_busy);
+
+ blk_complete_request(req);
+}
+
+static void scsi_softirq_done(struct request *rq)
+{
+ struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(rq);
+ unsigned long wait_for = (cmd->allowed + 1) * rq->timeout;
+ int disposition;
+
+ INIT_LIST_HEAD(&cmd->eh_entry);
+
+ atomic_inc(&cmd->device->iodone_cnt);
+ if (cmd->result)
+ atomic_inc(&cmd->device->ioerr_cnt);
+
+ disposition = scsi_decide_disposition(cmd);
+ if (disposition != SUCCESS &&
+ time_before(cmd->jiffies_at_alloc + wait_for, jiffies)) {
+ sdev_printk(KERN_ERR, cmd->device,
+ "timing out command, waited %lus\n",
+ wait_for/HZ);
+ disposition = SUCCESS;
+ }
+
+ scsi_log_completion(cmd, disposition);
+
+ switch (disposition) {
+ case SUCCESS:
+ scsi_finish_command(cmd);
+ break;
+ case NEEDS_RETRY:
+ scsi_queue_insert(cmd, SCSI_MLQUEUE_EH_RETRY);
+ break;
+ case ADD_TO_MLQUEUE:
+ scsi_queue_insert(cmd, SCSI_MLQUEUE_DEVICE_BUSY);
+ break;
+ default:
+ scsi_eh_scmd_add(cmd);
+ break;
+ }
+}
+
+/**
+ * scsi_dispatch_command - Dispatch a command to the low-level driver.
+ * @cmd: command block we are dispatching.
+ *
+ * Return: nonzero return request was rejected and device's queue needs to be
+ * plugged.
+ */
+static int scsi_dispatch_cmd(struct scsi_cmnd *cmd)
+{
+ struct Scsi_Host *host = cmd->device->host;
+ int rtn = 0;
+
+ atomic_inc(&cmd->device->iorequest_cnt);
+
+ /* check if the device is still usable */
+ if (unlikely(cmd->device->sdev_state == SDEV_DEL)) {
+ /* in SDEV_DEL we error all commands. DID_NO_CONNECT
+ * returns an immediate error upwards, and signals
+ * that the device is no longer present */
+ cmd->result = DID_NO_CONNECT << 16;
+ goto done;
+ }
+
+ /* Check to see if the scsi lld made this device blocked. */
+ if (unlikely(scsi_device_blocked(cmd->device))) {
+ /*
+ * in blocked state, the command is just put back on
+ * the device queue. The suspend state has already
+ * blocked the queue so future requests should not
+ * occur until the device transitions out of the
+ * suspend state.
+ */
+ SCSI_LOG_MLQUEUE(3, scmd_printk(KERN_INFO, cmd,
+ "queuecommand : device blocked\n"));
+ return SCSI_MLQUEUE_DEVICE_BUSY;
+ }
+
+ /* Store the LUN value in cmnd, if needed. */
+ if (cmd->device->lun_in_cdb)
+ cmd->cmnd[1] = (cmd->cmnd[1] & 0x1f) |
+ (cmd->device->lun << 5 & 0xe0);
+
+ scsi_log_send(cmd);
+
+ /*
+ * Before we queue this command, check if the command
+ * length exceeds what the host adapter can handle.
+ */
+ if (cmd->cmd_len > cmd->device->host->max_cmd_len) {
+ SCSI_LOG_MLQUEUE(3, scmd_printk(KERN_INFO, cmd,
+ "queuecommand : command too long. "
+ "cdb_size=%d host->max_cmd_len=%d\n",
+ cmd->cmd_len, cmd->device->host->max_cmd_len));
+ cmd->result = (DID_ABORT << 16);
+ goto done;
+ }
+
+ if (unlikely(host->shost_state == SHOST_DEL)) {
+ cmd->result = (DID_NO_CONNECT << 16);
+ goto done;
+
+ }
+
+ trace_scsi_dispatch_cmd_start(cmd);
+ rtn = host->hostt->queuecommand(host, cmd);
+ if (rtn) {
+ trace_scsi_dispatch_cmd_error(cmd, rtn);
+ if (rtn != SCSI_MLQUEUE_DEVICE_BUSY &&
+ rtn != SCSI_MLQUEUE_TARGET_BUSY)
+ rtn = SCSI_MLQUEUE_HOST_BUSY;
+
+ SCSI_LOG_MLQUEUE(3, scmd_printk(KERN_INFO, cmd,
+ "queuecommand : request rejected\n"));
+ }
+
+ return rtn;
+ done:
+ cmd->scsi_done(cmd);
+ return 0;
+}
+
+/**
+ * scsi_done - Invoke completion on finished SCSI command.
+ * @cmd: The SCSI Command for which a low-level device driver (LLDD) gives
+ * ownership back to SCSI Core -- i.e. the LLDD has finished with it.
+ *
+ * Description: This function is the mid-level's (SCSI Core) interrupt routine,
+ * which regains ownership of the SCSI command (de facto) from a LLDD, and
+ * calls blk_complete_request() for further processing.
+ *
+ * This function is interrupt context safe.
+ */
+static void scsi_done(struct scsi_cmnd *cmd)
+{
+ trace_scsi_dispatch_cmd_done(cmd);
+ blk_complete_request(cmd->request);
+}
+
+/*
+ * Function: scsi_request_fn()
+ *
+ * Purpose: Main strategy routine for SCSI.
+ *
+ * Arguments: q - Pointer to actual queue.
+ *
+ * Returns: Nothing
+ *
+ * Lock status: request queue lock assumed to be held when called.
+ *
+ * Note: See sd_zbc.c sd_zbc_write_lock_zone() for write order
+ * protection for ZBC disks.
+ */
+static void scsi_request_fn(struct request_queue *q)
+ __releases(q->queue_lock)
+ __acquires(q->queue_lock)
+{
+ struct scsi_device *sdev = q->queuedata;
+ struct Scsi_Host *shost;
+ struct scsi_cmnd *cmd;
+ struct request *req;
+
+ /*
+ * To start with, we keep looping until the queue is empty, or until
+ * the host is no longer able to accept any more requests.
+ */
+ shost = sdev->host;
+ for (;;) {
+ int rtn;
+ /*
+ * get next queueable request. We do this early to make sure
+ * that the request is fully prepared even if we cannot
+ * accept it.
+ */
+ req = blk_peek_request(q);
+ if (!req)
+ break;
+
+ if (unlikely(!scsi_device_online(sdev))) {
+ sdev_printk(KERN_ERR, sdev,
+ "rejecting I/O to offline device\n");
+ scsi_kill_request(req, q);
+ continue;
+ }
+
+ if (!scsi_dev_queue_ready(q, sdev))
+ break;
+
+ /*
+ * Remove the request from the request list.
+ */
+ if (!(blk_queue_tagged(q) && !blk_queue_start_tag(q, req)))
+ blk_start_request(req);
+
+ spin_unlock_irq(q->queue_lock);
+ cmd = blk_mq_rq_to_pdu(req);
+ if (cmd != req->special) {
+ printk(KERN_CRIT "impossible request in %s.\n"
+ "please mail a stack trace to "
+ "linux-scsi@vger.kernel.org\n",
+ __func__);
+ blk_dump_rq_flags(req, "foo");
+ BUG();
+ }
+
+ /*
+ * We hit this when the driver is using a host wide
+ * tag map. For device level tag maps the queue_depth check
+ * in the device ready fn would prevent us from trying
+ * to allocate a tag. Since the map is a shared host resource
+ * we add the dev to the starved list so it eventually gets
+ * a run when a tag is freed.
+ */
+ if (blk_queue_tagged(q) && !(req->rq_flags & RQF_QUEUED)) {
+ spin_lock_irq(shost->host_lock);
+ if (list_empty(&sdev->starved_entry))
+ list_add_tail(&sdev->starved_entry,
+ &shost->starved_list);
+ spin_unlock_irq(shost->host_lock);
+ goto not_ready;
+ }
+
+ if (!scsi_target_queue_ready(shost, sdev))
+ goto not_ready;
+
+ if (!scsi_host_queue_ready(q, shost, sdev))
+ goto host_not_ready;
+
+ if (sdev->simple_tags)
+ cmd->flags |= SCMD_TAGGED;
+ else
+ cmd->flags &= ~SCMD_TAGGED;
+
+ /*
+ * Finally, initialize any error handling parameters, and set up
+ * the timers for timeouts.
+ */
+ scsi_init_cmd_errh(cmd);
+
+ /*
+ * Dispatch the command to the low-level driver.
+ */
+ cmd->scsi_done = scsi_done;
+ rtn = scsi_dispatch_cmd(cmd);
+ if (rtn) {
+ scsi_queue_insert(cmd, rtn);
+ spin_lock_irq(q->queue_lock);
+ goto out_delay;
+ }
+ spin_lock_irq(q->queue_lock);
+ }
+
+ return;
+
+ host_not_ready:
+ if (scsi_target(sdev)->can_queue > 0)
+ atomic_dec(&scsi_target(sdev)->target_busy);
+ not_ready:
+ /*
+ * lock q, handle tag, requeue req, and decrement device_busy. We
+ * must return with queue_lock held.
+ *
+ * Decrementing device_busy without checking it is OK, as all such
+ * cases (host limits or settings) should run the queue at some
+ * later time.
+ */
+ spin_lock_irq(q->queue_lock);
+ blk_requeue_request(q, req);
+ atomic_dec(&sdev->device_busy);
+out_delay:
+ if (!atomic_read(&sdev->device_busy) && !scsi_device_blocked(sdev))
+ blk_delay_queue(q, SCSI_QUEUE_DELAY);
+}
+
+static inline blk_status_t prep_to_mq(int ret)
+{
+ switch (ret) {
+ case BLKPREP_OK:
+ return BLK_STS_OK;
+ case BLKPREP_DEFER:
+ return BLK_STS_RESOURCE;
+ default:
+ return BLK_STS_IOERR;
+ }
+}
+
+/* Size in bytes of the sg-list stored in the scsi-mq command-private data. */
+static unsigned int scsi_mq_sgl_size(struct Scsi_Host *shost)
+{
+ return min_t(unsigned int, shost->sg_tablesize, SG_CHUNK_SIZE) *
+ sizeof(struct scatterlist);
+}
+
+static int scsi_mq_prep_fn(struct request *req)
+{
+ struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(req);
+ struct scsi_device *sdev = req->q->queuedata;
+ struct Scsi_Host *shost = sdev->host;
+ struct scatterlist *sg;
+
+ scsi_init_command(sdev, cmd);
+
+ req->special = cmd;
+
+ cmd->request = req;
+
+ cmd->tag = req->tag;
+ cmd->prot_op = SCSI_PROT_NORMAL;
+
+ sg = (void *)cmd + sizeof(struct scsi_cmnd) + shost->hostt->cmd_size;
+ cmd->sdb.table.sgl = sg;
+
+ if (scsi_host_get_prot(shost)) {
+ memset(cmd->prot_sdb, 0, sizeof(struct scsi_data_buffer));
+
+ cmd->prot_sdb->table.sgl =
+ (struct scatterlist *)(cmd->prot_sdb + 1);
+ }
+
+ if (blk_bidi_rq(req)) {
+ struct request *next_rq = req->next_rq;
+ struct scsi_data_buffer *bidi_sdb = blk_mq_rq_to_pdu(next_rq);
+
+ memset(bidi_sdb, 0, sizeof(struct scsi_data_buffer));
+ bidi_sdb->table.sgl =
+ (struct scatterlist *)(bidi_sdb + 1);
+
+ next_rq->special = bidi_sdb;
+ }
+
+ blk_mq_start_request(req);
+
+ return scsi_setup_cmnd(sdev, req);
+}
+
+static void scsi_mq_done(struct scsi_cmnd *cmd)
+{
+ trace_scsi_dispatch_cmd_done(cmd);
+ blk_mq_complete_request(cmd->request);
+}
+
+static void scsi_mq_put_budget(struct blk_mq_hw_ctx *hctx)
+{
+ struct request_queue *q = hctx->queue;
+ struct scsi_device *sdev = q->queuedata;
+
+ atomic_dec(&sdev->device_busy);
+ put_device(&sdev->sdev_gendev);
+}
+
+static bool scsi_mq_get_budget(struct blk_mq_hw_ctx *hctx)
+{
+ struct request_queue *q = hctx->queue;
+ struct scsi_device *sdev = q->queuedata;
+
+ if (!get_device(&sdev->sdev_gendev))
+ goto out;
+ if (!scsi_dev_queue_ready(q, sdev))
+ goto out_put_device;
+
+ return true;
+
+out_put_device:
+ put_device(&sdev->sdev_gendev);
+out:
+ if (atomic_read(&sdev->device_busy) == 0 && !scsi_device_blocked(sdev))
+ blk_mq_delay_run_hw_queue(hctx, SCSI_QUEUE_DELAY);
+ return false;
+}
+
+static blk_status_t scsi_queue_rq(struct blk_mq_hw_ctx *hctx,
+ const struct blk_mq_queue_data *bd)
+{
+ struct request *req = bd->rq;
+ struct request_queue *q = req->q;
+ struct scsi_device *sdev = q->queuedata;
+ struct Scsi_Host *shost = sdev->host;
+ struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(req);
+ blk_status_t ret;
+ int reason;
+
+ ret = prep_to_mq(scsi_prep_state_check(sdev, req));
+ if (ret != BLK_STS_OK)
+ goto out_put_budget;
+
+ ret = BLK_STS_RESOURCE;
+ if (!scsi_target_queue_ready(shost, sdev))
+ goto out_put_budget;
+ if (!scsi_host_queue_ready(q, shost, sdev))
+ goto out_dec_target_busy;
+
+ if (!(req->rq_flags & RQF_DONTPREP)) {
+ ret = prep_to_mq(scsi_mq_prep_fn(req));
+ if (ret != BLK_STS_OK)
+ goto out_dec_host_busy;
+ req->rq_flags |= RQF_DONTPREP;
+ } else {
+ blk_mq_start_request(req);
+ }
+
+ if (sdev->simple_tags)
+ cmd->flags |= SCMD_TAGGED;
+ else
+ cmd->flags &= ~SCMD_TAGGED;
+
+ scsi_init_cmd_errh(cmd);
+ cmd->scsi_done = scsi_mq_done;
+
+ reason = scsi_dispatch_cmd(cmd);
+ if (reason) {
+ scsi_set_blocked(cmd, reason);
+ ret = BLK_STS_RESOURCE;
+ goto out_dec_host_busy;
+ }
+
+ return BLK_STS_OK;
+
+out_dec_host_busy:
+ scsi_dec_host_busy(shost);
+out_dec_target_busy:
+ if (scsi_target(sdev)->can_queue > 0)
+ atomic_dec(&scsi_target(sdev)->target_busy);
+out_put_budget:
+ scsi_mq_put_budget(hctx);
+ switch (ret) {
+ case BLK_STS_OK:
+ break;
+ case BLK_STS_RESOURCE:
+ if (atomic_read(&sdev->device_busy) ||
+ scsi_device_blocked(sdev))
+ ret = BLK_STS_DEV_RESOURCE;
+ break;
+ default:
+ /*
+ * Make sure to release all allocated ressources when
+ * we hit an error, as we will never see this command
+ * again.
+ */
+ if (req->rq_flags & RQF_DONTPREP)
+ scsi_mq_uninit_cmd(cmd);
+ break;
+ }
+ return ret;
+}
+
+static enum blk_eh_timer_return scsi_timeout(struct request *req,
+ bool reserved)
+{
+ if (reserved)
+ return BLK_EH_RESET_TIMER;
+ return scsi_times_out(req);
+}
+
+static int scsi_mq_init_request(struct blk_mq_tag_set *set, struct request *rq,
+ unsigned int hctx_idx, unsigned int numa_node)
+{
+ struct Scsi_Host *shost = set->driver_data;
+ const bool unchecked_isa_dma = shost->unchecked_isa_dma;
+ struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(rq);
+ struct scatterlist *sg;
+
+ if (unchecked_isa_dma)
+ cmd->flags |= SCMD_UNCHECKED_ISA_DMA;
+ cmd->sense_buffer = scsi_alloc_sense_buffer(unchecked_isa_dma,
+ GFP_KERNEL, numa_node);
+ if (!cmd->sense_buffer)
+ return -ENOMEM;
+ cmd->req.sense = cmd->sense_buffer;
+
+ if (scsi_host_get_prot(shost)) {
+ sg = (void *)cmd + sizeof(struct scsi_cmnd) +
+ shost->hostt->cmd_size;
+ cmd->prot_sdb = (void *)sg + scsi_mq_sgl_size(shost);
+ }
+
+ return 0;
+}
+
+static void scsi_mq_exit_request(struct blk_mq_tag_set *set, struct request *rq,
+ unsigned int hctx_idx)
+{
+ struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(rq);
+
+ scsi_free_sense_buffer(cmd->flags & SCMD_UNCHECKED_ISA_DMA,
+ cmd->sense_buffer);
+}
+
+static int scsi_map_queues(struct blk_mq_tag_set *set)
+{
+ struct Scsi_Host *shost = container_of(set, struct Scsi_Host, tag_set);
+
+ if (shost->hostt->map_queues)
+ return shost->hostt->map_queues(shost);
+ return blk_mq_map_queues(set);
+}
+
+void __scsi_init_queue(struct Scsi_Host *shost, struct request_queue *q)
+{
+ struct device *dev = shost->dma_dev;
+
+ /*
+ * this limit is imposed by hardware restrictions
+ */
+ blk_queue_max_segments(q, min_t(unsigned short, shost->sg_tablesize,
+ SG_MAX_SEGMENTS));
+
+ if (scsi_host_prot_dma(shost)) {
+ shost->sg_prot_tablesize =
+ min_not_zero(shost->sg_prot_tablesize,
+ (unsigned short)SCSI_MAX_PROT_SG_SEGMENTS);
+ BUG_ON(shost->sg_prot_tablesize < shost->sg_tablesize);
+ blk_queue_max_integrity_segments(q, shost->sg_prot_tablesize);
+ }
+
+ blk_queue_max_hw_sectors(q, shost->max_sectors);
+ if (shost->unchecked_isa_dma)
+ blk_queue_bounce_limit(q, BLK_BOUNCE_ISA);
+ blk_queue_segment_boundary(q, shost->dma_boundary);
+ dma_set_seg_boundary(dev, shost->dma_boundary);
+
+ blk_queue_max_segment_size(q, dma_get_max_seg_size(dev));
+
+ if (!shost->use_clustering)
+ q->limits.cluster = 0;
+
+ /*
+ * Set a reasonable default alignment: The larger of 32-byte (dword),
+ * which is a common minimum for HBAs, and the minimum DMA alignment,
+ * which is set by the platform.
+ *
+ * Devices that require a bigger alignment can increase it later.
+ */
+ blk_queue_dma_alignment(q, max(4, dma_get_cache_alignment()) - 1);
+}
+EXPORT_SYMBOL_GPL(__scsi_init_queue);
+
+static int scsi_old_init_rq(struct request_queue *q, struct request *rq,
+ gfp_t gfp)
+{
+ struct Scsi_Host *shost = q->rq_alloc_data;
+ const bool unchecked_isa_dma = shost->unchecked_isa_dma;
+ struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(rq);
+
+ memset(cmd, 0, sizeof(*cmd));
+
+ if (unchecked_isa_dma)
+ cmd->flags |= SCMD_UNCHECKED_ISA_DMA;
+ cmd->sense_buffer = scsi_alloc_sense_buffer(unchecked_isa_dma, gfp,
+ NUMA_NO_NODE);
+ if (!cmd->sense_buffer)
+ goto fail;
+ cmd->req.sense = cmd->sense_buffer;
+
+ if (scsi_host_get_prot(shost) >= SHOST_DIX_TYPE0_PROTECTION) {
+ cmd->prot_sdb = kmem_cache_zalloc(scsi_sdb_cache, gfp);
+ if (!cmd->prot_sdb)
+ goto fail_free_sense;
+ }
+
+ return 0;
+
+fail_free_sense:
+ scsi_free_sense_buffer(unchecked_isa_dma, cmd->sense_buffer);
+fail:
+ return -ENOMEM;
+}
+
+static void scsi_old_exit_rq(struct request_queue *q, struct request *rq)
+{
+ struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(rq);
+
+ if (cmd->prot_sdb)
+ kmem_cache_free(scsi_sdb_cache, cmd->prot_sdb);
+ scsi_free_sense_buffer(cmd->flags & SCMD_UNCHECKED_ISA_DMA,
+ cmd->sense_buffer);
+}
+
+struct request_queue *scsi_old_alloc_queue(struct scsi_device *sdev)
+{
+ struct Scsi_Host *shost = sdev->host;
+ struct request_queue *q;
+
+ q = blk_alloc_queue_node(GFP_KERNEL, NUMA_NO_NODE, NULL);
+ if (!q)
+ return NULL;
+ q->cmd_size = sizeof(struct scsi_cmnd) + shost->hostt->cmd_size;
+ q->rq_alloc_data = shost;
+ q->request_fn = scsi_request_fn;
+ q->init_rq_fn = scsi_old_init_rq;
+ q->exit_rq_fn = scsi_old_exit_rq;
+ q->initialize_rq_fn = scsi_initialize_rq;
+
+ if (blk_init_allocated_queue(q) < 0) {
+ blk_cleanup_queue(q);
+ return NULL;
+ }
+
+ __scsi_init_queue(shost, q);
+ blk_queue_flag_set(QUEUE_FLAG_SCSI_PASSTHROUGH, q);
+ blk_queue_prep_rq(q, scsi_prep_fn);
+ blk_queue_unprep_rq(q, scsi_unprep_fn);
+ blk_queue_softirq_done(q, scsi_softirq_done);
+ blk_queue_rq_timed_out(q, scsi_times_out);
+ blk_queue_lld_busy(q, scsi_lld_busy);
+ return q;
+}
+
+static const struct blk_mq_ops scsi_mq_ops = {
+ .get_budget = scsi_mq_get_budget,
+ .put_budget = scsi_mq_put_budget,
+ .queue_rq = scsi_queue_rq,
+ .complete = scsi_softirq_done,
+ .timeout = scsi_timeout,
+#ifdef CONFIG_BLK_DEBUG_FS
+ .show_rq = scsi_show_rq,
+#endif
+ .init_request = scsi_mq_init_request,
+ .exit_request = scsi_mq_exit_request,
+ .initialize_rq_fn = scsi_initialize_rq,
+ .map_queues = scsi_map_queues,
+};
+
+struct request_queue *scsi_mq_alloc_queue(struct scsi_device *sdev)
+{
+ sdev->request_queue = blk_mq_init_queue(&sdev->host->tag_set);
+ if (IS_ERR(sdev->request_queue))
+ return NULL;
+
+ sdev->request_queue->queuedata = sdev;
+ __scsi_init_queue(sdev->host, sdev->request_queue);
+ blk_queue_flag_set(QUEUE_FLAG_SCSI_PASSTHROUGH, sdev->request_queue);
+ return sdev->request_queue;
+}
+
+int scsi_mq_setup_tags(struct Scsi_Host *shost)
+{
+ unsigned int cmd_size, sgl_size;
+
+ sgl_size = scsi_mq_sgl_size(shost);
+ cmd_size = sizeof(struct scsi_cmnd) + shost->hostt->cmd_size + sgl_size;
+ if (scsi_host_get_prot(shost))
+ cmd_size += sizeof(struct scsi_data_buffer) + sgl_size;
+
+ memset(&shost->tag_set, 0, sizeof(shost->tag_set));
+ shost->tag_set.ops = &scsi_mq_ops;
+ shost->tag_set.nr_hw_queues = shost->nr_hw_queues ? : 1;
+ shost->tag_set.queue_depth = shost->can_queue;
+ shost->tag_set.cmd_size = cmd_size;
+ shost->tag_set.numa_node = NUMA_NO_NODE;
+ shost->tag_set.flags = BLK_MQ_F_SHOULD_MERGE | BLK_MQ_F_SG_MERGE;
+ shost->tag_set.flags |=
+ BLK_ALLOC_POLICY_TO_MQ_FLAG(shost->hostt->tag_alloc_policy);
+ shost->tag_set.driver_data = shost;
+
+ return blk_mq_alloc_tag_set(&shost->tag_set);
+}
+
+void scsi_mq_destroy_tags(struct Scsi_Host *shost)
+{
+ blk_mq_free_tag_set(&shost->tag_set);
+}
+
+/**
+ * scsi_device_from_queue - return sdev associated with a request_queue
+ * @q: The request queue to return the sdev from
+ *
+ * Return the sdev associated with a request queue or NULL if the
+ * request_queue does not reference a SCSI device.
+ */
+struct scsi_device *scsi_device_from_queue(struct request_queue *q)
+{
+ struct scsi_device *sdev = NULL;
+
+ if (q->mq_ops) {
+ if (q->mq_ops == &scsi_mq_ops)
+ sdev = q->queuedata;
+ } else if (q->request_fn == scsi_request_fn)
+ sdev = q->queuedata;
+ if (!sdev || !get_device(&sdev->sdev_gendev))
+ sdev = NULL;
+
+ return sdev;
+}
+EXPORT_SYMBOL_GPL(scsi_device_from_queue);
+
+/*
+ * Function: scsi_block_requests()
+ *
+ * Purpose: Utility function used by low-level drivers to prevent further
+ * commands from being queued to the device.
+ *
+ * Arguments: shost - Host in question
+ *
+ * Returns: Nothing
+ *
+ * Lock status: No locks are assumed held.
+ *
+ * Notes: There is no timer nor any other means by which the requests
+ * get unblocked other than the low-level driver calling
+ * scsi_unblock_requests().
+ */
+void scsi_block_requests(struct Scsi_Host *shost)
+{
+ shost->host_self_blocked = 1;
+}
+EXPORT_SYMBOL(scsi_block_requests);
+
+/*
+ * Function: scsi_unblock_requests()
+ *
+ * Purpose: Utility function used by low-level drivers to allow further
+ * commands from being queued to the device.
+ *
+ * Arguments: shost - Host in question
+ *
+ * Returns: Nothing
+ *
+ * Lock status: No locks are assumed held.
+ *
+ * Notes: There is no timer nor any other means by which the requests
+ * get unblocked other than the low-level driver calling
+ * scsi_unblock_requests().
+ *
+ * This is done as an API function so that changes to the
+ * internals of the scsi mid-layer won't require wholesale
+ * changes to drivers that use this feature.
+ */
+void scsi_unblock_requests(struct Scsi_Host *shost)
+{
+ shost->host_self_blocked = 0;
+ scsi_run_host_queues(shost);
+}
+EXPORT_SYMBOL(scsi_unblock_requests);
+
+int __init scsi_init_queue(void)
+{
+ scsi_sdb_cache = kmem_cache_create("scsi_data_buffer",
+ sizeof(struct scsi_data_buffer),
+ 0, 0, NULL);
+ if (!scsi_sdb_cache) {
+ printk(KERN_ERR "SCSI: can't init scsi sdb cache\n");
+ return -ENOMEM;
+ }
+
+ return 0;
+}
+
+void scsi_exit_queue(void)
+{
+ kmem_cache_destroy(scsi_sense_cache);
+ kmem_cache_destroy(scsi_sense_isadma_cache);
+ kmem_cache_destroy(scsi_sdb_cache);
+}
+
+/**
+ * scsi_mode_select - issue a mode select
+ * @sdev: SCSI device to be queried
+ * @pf: Page format bit (1 == standard, 0 == vendor specific)
+ * @sp: Save page bit (0 == don't save, 1 == save)
+ * @modepage: mode page being requested
+ * @buffer: request buffer (may not be smaller than eight bytes)
+ * @len: length of request buffer.
+ * @timeout: command timeout
+ * @retries: number of retries before failing
+ * @data: returns a structure abstracting the mode header data
+ * @sshdr: place to put sense data (or NULL if no sense to be collected).
+ * must be SCSI_SENSE_BUFFERSIZE big.
+ *
+ * Returns zero if successful; negative error number or scsi
+ * status on error
+ *
+ */
+int
+scsi_mode_select(struct scsi_device *sdev, int pf, int sp, int modepage,
+ unsigned char *buffer, int len, int timeout, int retries,
+ struct scsi_mode_data *data, struct scsi_sense_hdr *sshdr)
+{
+ unsigned char cmd[10];
+ unsigned char *real_buffer;
+ int ret;
+
+ memset(cmd, 0, sizeof(cmd));
+ cmd[1] = (pf ? 0x10 : 0) | (sp ? 0x01 : 0);
+
+ if (sdev->use_10_for_ms) {
+ if (len > 65535)
+ return -EINVAL;
+ real_buffer = kmalloc(8 + len, GFP_KERNEL);
+ if (!real_buffer)
+ return -ENOMEM;
+ memcpy(real_buffer + 8, buffer, len);
+ len += 8;
+ real_buffer[0] = 0;
+ real_buffer[1] = 0;
+ real_buffer[2] = data->medium_type;
+ real_buffer[3] = data->device_specific;
+ real_buffer[4] = data->longlba ? 0x01 : 0;
+ real_buffer[5] = 0;
+ real_buffer[6] = data->block_descriptor_length >> 8;
+ real_buffer[7] = data->block_descriptor_length;
+
+ cmd[0] = MODE_SELECT_10;
+ cmd[7] = len >> 8;
+ cmd[8] = len;
+ } else {
+ if (len > 255 || data->block_descriptor_length > 255 ||
+ data->longlba)
+ return -EINVAL;
+
+ real_buffer = kmalloc(4 + len, GFP_KERNEL);
+ if (!real_buffer)
+ return -ENOMEM;
+ memcpy(real_buffer + 4, buffer, len);
+ len += 4;
+ real_buffer[0] = 0;
+ real_buffer[1] = data->medium_type;
+ real_buffer[2] = data->device_specific;
+ real_buffer[3] = data->block_descriptor_length;
+
+
+ cmd[0] = MODE_SELECT;
+ cmd[4] = len;
+ }
+
+ ret = scsi_execute_req(sdev, cmd, DMA_TO_DEVICE, real_buffer, len,
+ sshdr, timeout, retries, NULL);
+ kfree(real_buffer);
+ return ret;
+}
+EXPORT_SYMBOL_GPL(scsi_mode_select);
+
+/**
+ * scsi_mode_sense - issue a mode sense, falling back from 10 to six bytes if necessary.
+ * @sdev: SCSI device to be queried
+ * @dbd: set if mode sense will allow block descriptors to be returned
+ * @modepage: mode page being requested
+ * @buffer: request buffer (may not be smaller than eight bytes)
+ * @len: length of request buffer.
+ * @timeout: command timeout
+ * @retries: number of retries before failing
+ * @data: returns a structure abstracting the mode header data
+ * @sshdr: place to put sense data (or NULL if no sense to be collected).
+ * must be SCSI_SENSE_BUFFERSIZE big.
+ *
+ * Returns zero if unsuccessful, or the header offset (either 4
+ * or 8 depending on whether a six or ten byte command was
+ * issued) if successful.
+ */
+int
+scsi_mode_sense(struct scsi_device *sdev, int dbd, int modepage,
+ unsigned char *buffer, int len, int timeout, int retries,
+ struct scsi_mode_data *data, struct scsi_sense_hdr *sshdr)
+{
+ unsigned char cmd[12];
+ int use_10_for_ms;
+ int header_length;
+ int result, retry_count = retries;
+ struct scsi_sense_hdr my_sshdr;
+
+ memset(data, 0, sizeof(*data));
+ memset(&cmd[0], 0, 12);
+ cmd[1] = dbd & 0x18; /* allows DBD and LLBA bits */
+ cmd[2] = modepage;
+
+ /* caller might not be interested in sense, but we need it */
+ if (!sshdr)
+ sshdr = &my_sshdr;
+
+ retry:
+ use_10_for_ms = sdev->use_10_for_ms;
+
+ if (use_10_for_ms) {
+ if (len < 8)
+ len = 8;
+
+ cmd[0] = MODE_SENSE_10;
+ cmd[8] = len;
+ header_length = 8;
+ } else {
+ if (len < 4)
+ len = 4;
+
+ cmd[0] = MODE_SENSE;
+ cmd[4] = len;
+ header_length = 4;
+ }
+
+ memset(buffer, 0, len);
+
+ result = scsi_execute_req(sdev, cmd, DMA_FROM_DEVICE, buffer, len,
+ sshdr, timeout, retries, NULL);
+
+ /* This code looks awful: what it's doing is making sure an
+ * ILLEGAL REQUEST sense return identifies the actual command
+ * byte as the problem. MODE_SENSE commands can return
+ * ILLEGAL REQUEST if the code page isn't supported */
+
+ if (use_10_for_ms && !scsi_status_is_good(result) &&
+ driver_byte(result) == DRIVER_SENSE) {
+ if (scsi_sense_valid(sshdr)) {
+ if ((sshdr->sense_key == ILLEGAL_REQUEST) &&
+ (sshdr->asc == 0x20) && (sshdr->ascq == 0)) {
+ /*
+ * Invalid command operation code
+ */
+ sdev->use_10_for_ms = 0;
+ goto retry;
+ }
+ }
+ }
+
+ if(scsi_status_is_good(result)) {
+ if (unlikely(buffer[0] == 0x86 && buffer[1] == 0x0b &&
+ (modepage == 6 || modepage == 8))) {
+ /* Initio breakage? */
+ header_length = 0;
+ data->length = 13;
+ data->medium_type = 0;
+ data->device_specific = 0;
+ data->longlba = 0;
+ data->block_descriptor_length = 0;
+ } else if(use_10_for_ms) {
+ data->length = buffer[0]*256 + buffer[1] + 2;
+ data->medium_type = buffer[2];
+ data->device_specific = buffer[3];
+ data->longlba = buffer[4] & 0x01;
+ data->block_descriptor_length = buffer[6]*256
+ + buffer[7];
+ } else {
+ data->length = buffer[0] + 1;
+ data->medium_type = buffer[1];
+ data->device_specific = buffer[2];
+ data->block_descriptor_length = buffer[3];
+ }
+ data->header_length = header_length;
+ } else if ((status_byte(result) == CHECK_CONDITION) &&
+ scsi_sense_valid(sshdr) &&
+ sshdr->sense_key == UNIT_ATTENTION && retry_count) {
+ retry_count--;
+ goto retry;
+ }
+
+ return result;
+}
+EXPORT_SYMBOL(scsi_mode_sense);
+
+/**
+ * scsi_test_unit_ready - test if unit is ready
+ * @sdev: scsi device to change the state of.
+ * @timeout: command timeout
+ * @retries: number of retries before failing
+ * @sshdr: outpout pointer for decoded sense information.
+ *
+ * Returns zero if unsuccessful or an error if TUR failed. For
+ * removable media, UNIT_ATTENTION sets ->changed flag.
+ **/
+int
+scsi_test_unit_ready(struct scsi_device *sdev, int timeout, int retries,
+ struct scsi_sense_hdr *sshdr)
+{
+ char cmd[] = {
+ TEST_UNIT_READY, 0, 0, 0, 0, 0,
+ };
+ int result;
+
+ /* try to eat the UNIT_ATTENTION if there are enough retries */
+ do {
+ result = scsi_execute_req(sdev, cmd, DMA_NONE, NULL, 0, sshdr,
+ timeout, 1, NULL);
+ if (sdev->removable && scsi_sense_valid(sshdr) &&
+ sshdr->sense_key == UNIT_ATTENTION)
+ sdev->changed = 1;
+ } while (scsi_sense_valid(sshdr) &&
+ sshdr->sense_key == UNIT_ATTENTION && --retries);
+
+ return result;
+}
+EXPORT_SYMBOL(scsi_test_unit_ready);
+
+/**
+ * scsi_device_set_state - Take the given device through the device state model.
+ * @sdev: scsi device to change the state of.
+ * @state: state to change to.
+ *
+ * Returns zero if successful or an error if the requested
+ * transition is illegal.
+ */
+int
+scsi_device_set_state(struct scsi_device *sdev, enum scsi_device_state state)
+{
+ enum scsi_device_state oldstate = sdev->sdev_state;
+
+ if (state == oldstate)
+ return 0;
+
+ switch (state) {
+ case SDEV_CREATED:
+ switch (oldstate) {
+ case SDEV_CREATED_BLOCK:
+ break;
+ default:
+ goto illegal;
+ }
+ break;
+
+ case SDEV_RUNNING:
+ switch (oldstate) {
+ case SDEV_CREATED:
+ case SDEV_OFFLINE:
+ case SDEV_TRANSPORT_OFFLINE:
+ case SDEV_QUIESCE:
+ case SDEV_BLOCK:
+ break;
+ default:
+ goto illegal;
+ }
+ break;
+
+ case SDEV_QUIESCE:
+ switch (oldstate) {
+ case SDEV_RUNNING:
+ case SDEV_OFFLINE:
+ case SDEV_TRANSPORT_OFFLINE:
+ break;
+ default:
+ goto illegal;
+ }
+ break;
+
+ case SDEV_OFFLINE:
+ case SDEV_TRANSPORT_OFFLINE:
+ switch (oldstate) {
+ case SDEV_CREATED:
+ case SDEV_RUNNING:
+ case SDEV_QUIESCE:
+ case SDEV_BLOCK:
+ break;
+ default:
+ goto illegal;
+ }
+ break;
+
+ case SDEV_BLOCK:
+ switch (oldstate) {
+ case SDEV_RUNNING:
+ case SDEV_CREATED_BLOCK:
+ break;
+ default:
+ goto illegal;
+ }
+ break;
+
+ case SDEV_CREATED_BLOCK:
+ switch (oldstate) {
+ case SDEV_CREATED:
+ break;
+ default:
+ goto illegal;
+ }
+ break;
+
+ case SDEV_CANCEL:
+ switch (oldstate) {
+ case SDEV_CREATED:
+ case SDEV_RUNNING:
+ case SDEV_QUIESCE:
+ case SDEV_OFFLINE:
+ case SDEV_TRANSPORT_OFFLINE:
+ break;
+ default:
+ goto illegal;
+ }
+ break;
+
+ case SDEV_DEL:
+ switch (oldstate) {
+ case SDEV_CREATED:
+ case SDEV_RUNNING:
+ case SDEV_OFFLINE:
+ case SDEV_TRANSPORT_OFFLINE:
+ case SDEV_CANCEL:
+ case SDEV_BLOCK:
+ case SDEV_CREATED_BLOCK:
+ break;
+ default:
+ goto illegal;
+ }
+ break;
+
+ }
+ sdev->sdev_state = state;
+ return 0;
+
+ illegal:
+ SCSI_LOG_ERROR_RECOVERY(1,
+ sdev_printk(KERN_ERR, sdev,
+ "Illegal state transition %s->%s",
+ scsi_device_state_name(oldstate),
+ scsi_device_state_name(state))
+ );
+ return -EINVAL;
+}
+EXPORT_SYMBOL(scsi_device_set_state);
+
+/**
+ * sdev_evt_emit - emit a single SCSI device uevent
+ * @sdev: associated SCSI device
+ * @evt: event to emit
+ *
+ * Send a single uevent (scsi_event) to the associated scsi_device.
+ */
+static void scsi_evt_emit(struct scsi_device *sdev, struct scsi_event *evt)
+{
+ int idx = 0;
+ char *envp[3];
+
+ switch (evt->evt_type) {
+ case SDEV_EVT_MEDIA_CHANGE:
+ envp[idx++] = "SDEV_MEDIA_CHANGE=1";
+ break;
+ case SDEV_EVT_INQUIRY_CHANGE_REPORTED:
+ scsi_rescan_device(&sdev->sdev_gendev);
+ envp[idx++] = "SDEV_UA=INQUIRY_DATA_HAS_CHANGED";
+ break;
+ case SDEV_EVT_CAPACITY_CHANGE_REPORTED:
+ envp[idx++] = "SDEV_UA=CAPACITY_DATA_HAS_CHANGED";
+ break;
+ case SDEV_EVT_SOFT_THRESHOLD_REACHED_REPORTED:
+ envp[idx++] = "SDEV_UA=THIN_PROVISIONING_SOFT_THRESHOLD_REACHED";
+ break;
+ case SDEV_EVT_MODE_PARAMETER_CHANGE_REPORTED:
+ envp[idx++] = "SDEV_UA=MODE_PARAMETERS_CHANGED";
+ break;
+ case SDEV_EVT_LUN_CHANGE_REPORTED:
+ envp[idx++] = "SDEV_UA=REPORTED_LUNS_DATA_HAS_CHANGED";
+ break;
+ case SDEV_EVT_ALUA_STATE_CHANGE_REPORTED:
+ envp[idx++] = "SDEV_UA=ASYMMETRIC_ACCESS_STATE_CHANGED";
+ break;
+ case SDEV_EVT_POWER_ON_RESET_OCCURRED:
+ envp[idx++] = "SDEV_UA=POWER_ON_RESET_OCCURRED";
+ break;
+ default:
+ /* do nothing */
+ break;
+ }
+
+ envp[idx++] = NULL;
+
+ kobject_uevent_env(&sdev->sdev_gendev.kobj, KOBJ_CHANGE, envp);
+}
+
+/**
+ * sdev_evt_thread - send a uevent for each scsi event
+ * @work: work struct for scsi_device
+ *
+ * Dispatch queued events to their associated scsi_device kobjects
+ * as uevents.
+ */
+void scsi_evt_thread(struct work_struct *work)
+{
+ struct scsi_device *sdev;
+ enum scsi_device_event evt_type;
+ LIST_HEAD(event_list);
+
+ sdev = container_of(work, struct scsi_device, event_work);
+
+ for (evt_type = SDEV_EVT_FIRST; evt_type <= SDEV_EVT_LAST; evt_type++)
+ if (test_and_clear_bit(evt_type, sdev->pending_events))
+ sdev_evt_send_simple(sdev, evt_type, GFP_KERNEL);
+
+ while (1) {
+ struct scsi_event *evt;
+ struct list_head *this, *tmp;
+ unsigned long flags;
+
+ spin_lock_irqsave(&sdev->list_lock, flags);
+ list_splice_init(&sdev->event_list, &event_list);
+ spin_unlock_irqrestore(&sdev->list_lock, flags);
+
+ if (list_empty(&event_list))
+ break;
+
+ list_for_each_safe(this, tmp, &event_list) {
+ evt = list_entry(this, struct scsi_event, node);
+ list_del(&evt->node);
+ scsi_evt_emit(sdev, evt);
+ kfree(evt);
+ }
+ }
+}
+
+/**
+ * sdev_evt_send - send asserted event to uevent thread
+ * @sdev: scsi_device event occurred on
+ * @evt: event to send
+ *
+ * Assert scsi device event asynchronously.
+ */
+void sdev_evt_send(struct scsi_device *sdev, struct scsi_event *evt)
+{
+ unsigned long flags;
+
+#if 0
+ /* FIXME: currently this check eliminates all media change events
+ * for polled devices. Need to update to discriminate between AN
+ * and polled events */
+ if (!test_bit(evt->evt_type, sdev->supported_events)) {
+ kfree(evt);
+ return;
+ }
+#endif
+
+ spin_lock_irqsave(&sdev->list_lock, flags);
+ list_add_tail(&evt->node, &sdev->event_list);
+ schedule_work(&sdev->event_work);
+ spin_unlock_irqrestore(&sdev->list_lock, flags);
+}
+EXPORT_SYMBOL_GPL(sdev_evt_send);
+
+/**
+ * sdev_evt_alloc - allocate a new scsi event
+ * @evt_type: type of event to allocate
+ * @gfpflags: GFP flags for allocation
+ *
+ * Allocates and returns a new scsi_event.
+ */
+struct scsi_event *sdev_evt_alloc(enum scsi_device_event evt_type,
+ gfp_t gfpflags)
+{
+ struct scsi_event *evt = kzalloc(sizeof(struct scsi_event), gfpflags);
+ if (!evt)
+ return NULL;
+
+ evt->evt_type = evt_type;
+ INIT_LIST_HEAD(&evt->node);
+
+ /* evt_type-specific initialization, if any */
+ switch (evt_type) {
+ case SDEV_EVT_MEDIA_CHANGE:
+ case SDEV_EVT_INQUIRY_CHANGE_REPORTED:
+ case SDEV_EVT_CAPACITY_CHANGE_REPORTED:
+ case SDEV_EVT_SOFT_THRESHOLD_REACHED_REPORTED:
+ case SDEV_EVT_MODE_PARAMETER_CHANGE_REPORTED:
+ case SDEV_EVT_LUN_CHANGE_REPORTED:
+ case SDEV_EVT_ALUA_STATE_CHANGE_REPORTED:
+ case SDEV_EVT_POWER_ON_RESET_OCCURRED:
+ default:
+ /* do nothing */
+ break;
+ }
+
+ return evt;
+}
+EXPORT_SYMBOL_GPL(sdev_evt_alloc);
+
+/**
+ * sdev_evt_send_simple - send asserted event to uevent thread
+ * @sdev: scsi_device event occurred on
+ * @evt_type: type of event to send
+ * @gfpflags: GFP flags for allocation
+ *
+ * Assert scsi device event asynchronously, given an event type.
+ */
+void sdev_evt_send_simple(struct scsi_device *sdev,
+ enum scsi_device_event evt_type, gfp_t gfpflags)
+{
+ struct scsi_event *evt = sdev_evt_alloc(evt_type, gfpflags);
+ if (!evt) {
+ sdev_printk(KERN_ERR, sdev, "event %d eaten due to OOM\n",
+ evt_type);
+ return;
+ }
+
+ sdev_evt_send(sdev, evt);
+}
+EXPORT_SYMBOL_GPL(sdev_evt_send_simple);
+
+/**
+ * scsi_request_fn_active() - number of kernel threads inside scsi_request_fn()
+ * @sdev: SCSI device to count the number of scsi_request_fn() callers for.
+ */
+static int scsi_request_fn_active(struct scsi_device *sdev)
+{
+ struct request_queue *q = sdev->request_queue;
+ int request_fn_active;
+
+ WARN_ON_ONCE(sdev->host->use_blk_mq);
+
+ spin_lock_irq(q->queue_lock);
+ request_fn_active = q->request_fn_active;
+ spin_unlock_irq(q->queue_lock);
+
+ return request_fn_active;
+}
+
+/**
+ * scsi_wait_for_queuecommand() - wait for ongoing queuecommand() calls
+ * @sdev: SCSI device pointer.
+ *
+ * Wait until the ongoing shost->hostt->queuecommand() calls that are
+ * invoked from scsi_request_fn() have finished.
+ */
+static void scsi_wait_for_queuecommand(struct scsi_device *sdev)
+{
+ WARN_ON_ONCE(sdev->host->use_blk_mq);
+
+ while (scsi_request_fn_active(sdev))
+ msleep(20);
+}
+
+/**
+ * scsi_device_quiesce - Block user issued commands.
+ * @sdev: scsi device to quiesce.
+ *
+ * This works by trying to transition to the SDEV_QUIESCE state
+ * (which must be a legal transition). When the device is in this
+ * state, only special requests will be accepted, all others will
+ * be deferred. Since special requests may also be requeued requests,
+ * a successful return doesn't guarantee the device will be
+ * totally quiescent.
+ *
+ * Must be called with user context, may sleep.
+ *
+ * Returns zero if unsuccessful or an error if not.
+ */
+int
+scsi_device_quiesce(struct scsi_device *sdev)
+{
+ struct request_queue *q = sdev->request_queue;
+ int err;
+
+ /*
+ * It is allowed to call scsi_device_quiesce() multiple times from
+ * the same context but concurrent scsi_device_quiesce() calls are
+ * not allowed.
+ */
+ WARN_ON_ONCE(sdev->quiesced_by && sdev->quiesced_by != current);
+
+ blk_set_preempt_only(q);
+
+ blk_mq_freeze_queue(q);
+ /*
+ * Ensure that the effect of blk_set_preempt_only() will be visible
+ * for percpu_ref_tryget() callers that occur after the queue
+ * unfreeze even if the queue was already frozen before this function
+ * was called. See also https://lwn.net/Articles/573497/.
+ */
+ synchronize_rcu();
+ blk_mq_unfreeze_queue(q);
+
+ mutex_lock(&sdev->state_mutex);
+ err = scsi_device_set_state(sdev, SDEV_QUIESCE);
+ if (err == 0)
+ sdev->quiesced_by = current;
+ else
+ blk_clear_preempt_only(q);
+ mutex_unlock(&sdev->state_mutex);
+
+ return err;
+}
+EXPORT_SYMBOL(scsi_device_quiesce);
+
+/**
+ * scsi_device_resume - Restart user issued commands to a quiesced device.
+ * @sdev: scsi device to resume.
+ *
+ * Moves the device from quiesced back to running and restarts the
+ * queues.
+ *
+ * Must be called with user context, may sleep.
+ */
+void scsi_device_resume(struct scsi_device *sdev)
+{
+ /* check if the device state was mutated prior to resume, and if
+ * so assume the state is being managed elsewhere (for example
+ * device deleted during suspend)
+ */
+ mutex_lock(&sdev->state_mutex);
+ WARN_ON_ONCE(!sdev->quiesced_by);
+ sdev->quiesced_by = NULL;
+ blk_clear_preempt_only(sdev->request_queue);
+ if (sdev->sdev_state == SDEV_QUIESCE)
+ scsi_device_set_state(sdev, SDEV_RUNNING);
+ mutex_unlock(&sdev->state_mutex);
+}
+EXPORT_SYMBOL(scsi_device_resume);
+
+static void
+device_quiesce_fn(struct scsi_device *sdev, void *data)
+{
+ scsi_device_quiesce(sdev);
+}
+
+void
+scsi_target_quiesce(struct scsi_target *starget)
+{
+ starget_for_each_device(starget, NULL, device_quiesce_fn);
+}
+EXPORT_SYMBOL(scsi_target_quiesce);
+
+static void
+device_resume_fn(struct scsi_device *sdev, void *data)
+{
+ scsi_device_resume(sdev);
+}
+
+void
+scsi_target_resume(struct scsi_target *starget)
+{
+ starget_for_each_device(starget, NULL, device_resume_fn);
+}
+EXPORT_SYMBOL(scsi_target_resume);
+
+/**
+ * scsi_internal_device_block_nowait - try to transition to the SDEV_BLOCK state
+ * @sdev: device to block
+ *
+ * Pause SCSI command processing on the specified device. Does not sleep.
+ *
+ * Returns zero if successful or a negative error code upon failure.
+ *
+ * Notes:
+ * This routine transitions the device to the SDEV_BLOCK state (which must be
+ * a legal transition). When the device is in this state, command processing
+ * is paused until the device leaves the SDEV_BLOCK state. See also
+ * scsi_internal_device_unblock_nowait().
+ */
+int scsi_internal_device_block_nowait(struct scsi_device *sdev)
+{
+ struct request_queue *q = sdev->request_queue;
+ unsigned long flags;
+ int err = 0;
+
+ err = scsi_device_set_state(sdev, SDEV_BLOCK);
+ if (err) {
+ err = scsi_device_set_state(sdev, SDEV_CREATED_BLOCK);
+
+ if (err)
+ return err;
+ }
+
+ /*
+ * The device has transitioned to SDEV_BLOCK. Stop the
+ * block layer from calling the midlayer with this device's
+ * request queue.
+ */
+ if (q->mq_ops) {
+ blk_mq_quiesce_queue_nowait(q);
+ } else {
+ spin_lock_irqsave(q->queue_lock, flags);
+ blk_stop_queue(q);
+ spin_unlock_irqrestore(q->queue_lock, flags);
+ }
+
+ return 0;
+}
+EXPORT_SYMBOL_GPL(scsi_internal_device_block_nowait);
+
+/**
+ * scsi_internal_device_block - try to transition to the SDEV_BLOCK state
+ * @sdev: device to block
+ *
+ * Pause SCSI command processing on the specified device and wait until all
+ * ongoing scsi_request_fn() / scsi_queue_rq() calls have finished. May sleep.
+ *
+ * Returns zero if successful or a negative error code upon failure.
+ *
+ * Note:
+ * This routine transitions the device to the SDEV_BLOCK state (which must be
+ * a legal transition). When the device is in this state, command processing
+ * is paused until the device leaves the SDEV_BLOCK state. See also
+ * scsi_internal_device_unblock().
+ *
+ * To do: avoid that scsi_send_eh_cmnd() calls queuecommand() after
+ * scsi_internal_device_block() has blocked a SCSI device and also
+ * remove the rport mutex lock and unlock calls from srp_queuecommand().
+ */
+static int scsi_internal_device_block(struct scsi_device *sdev)
+{
+ struct request_queue *q = sdev->request_queue;
+ int err;
+
+ mutex_lock(&sdev->state_mutex);
+ err = scsi_internal_device_block_nowait(sdev);
+ if (err == 0) {
+ if (q->mq_ops)
+ blk_mq_quiesce_queue(q);
+ else
+ scsi_wait_for_queuecommand(sdev);
+ }
+ mutex_unlock(&sdev->state_mutex);
+
+ return err;
+}
+
+void scsi_start_queue(struct scsi_device *sdev)
+{
+ struct request_queue *q = sdev->request_queue;
+ unsigned long flags;
+
+ if (q->mq_ops) {
+ blk_mq_unquiesce_queue(q);
+ } else {
+ spin_lock_irqsave(q->queue_lock, flags);
+ blk_start_queue(q);
+ spin_unlock_irqrestore(q->queue_lock, flags);
+ }
+}
+
+/**
+ * scsi_internal_device_unblock_nowait - resume a device after a block request
+ * @sdev: device to resume
+ * @new_state: state to set the device to after unblocking
+ *
+ * Restart the device queue for a previously suspended SCSI device. Does not
+ * sleep.
+ *
+ * Returns zero if successful or a negative error code upon failure.
+ *
+ * Notes:
+ * This routine transitions the device to the SDEV_RUNNING state or to one of
+ * the offline states (which must be a legal transition) allowing the midlayer
+ * to goose the queue for this device.
+ */
+int scsi_internal_device_unblock_nowait(struct scsi_device *sdev,
+ enum scsi_device_state new_state)
+{
+ /*
+ * Try to transition the scsi device to SDEV_RUNNING or one of the
+ * offlined states and goose the device queue if successful.
+ */
+ switch (sdev->sdev_state) {
+ case SDEV_BLOCK:
+ case SDEV_TRANSPORT_OFFLINE:
+ sdev->sdev_state = new_state;
+ break;
+ case SDEV_CREATED_BLOCK:
+ if (new_state == SDEV_TRANSPORT_OFFLINE ||
+ new_state == SDEV_OFFLINE)
+ sdev->sdev_state = new_state;
+ else
+ sdev->sdev_state = SDEV_CREATED;
+ break;
+ case SDEV_CANCEL:
+ case SDEV_OFFLINE:
+ break;
+ default:
+ return -EINVAL;
+ }
+ scsi_start_queue(sdev);
+
+ return 0;
+}
+EXPORT_SYMBOL_GPL(scsi_internal_device_unblock_nowait);
+
+/**
+ * scsi_internal_device_unblock - resume a device after a block request
+ * @sdev: device to resume
+ * @new_state: state to set the device to after unblocking
+ *
+ * Restart the device queue for a previously suspended SCSI device. May sleep.
+ *
+ * Returns zero if successful or a negative error code upon failure.
+ *
+ * Notes:
+ * This routine transitions the device to the SDEV_RUNNING state or to one of
+ * the offline states (which must be a legal transition) allowing the midlayer
+ * to goose the queue for this device.
+ */
+static int scsi_internal_device_unblock(struct scsi_device *sdev,
+ enum scsi_device_state new_state)
+{
+ int ret;
+
+ mutex_lock(&sdev->state_mutex);
+ ret = scsi_internal_device_unblock_nowait(sdev, new_state);
+ mutex_unlock(&sdev->state_mutex);
+
+ return ret;
+}
+
+static void
+device_block(struct scsi_device *sdev, void *data)
+{
+ scsi_internal_device_block(sdev);
+}
+
+static int
+target_block(struct device *dev, void *data)
+{
+ if (scsi_is_target_device(dev))
+ starget_for_each_device(to_scsi_target(dev), NULL,
+ device_block);
+ return 0;
+}
+
+void
+scsi_target_block(struct device *dev)
+{
+ if (scsi_is_target_device(dev))
+ starget_for_each_device(to_scsi_target(dev), NULL,
+ device_block);
+ else
+ device_for_each_child(dev, NULL, target_block);
+}
+EXPORT_SYMBOL_GPL(scsi_target_block);
+
+static void
+device_unblock(struct scsi_device *sdev, void *data)
+{
+ scsi_internal_device_unblock(sdev, *(enum scsi_device_state *)data);
+}
+
+static int
+target_unblock(struct device *dev, void *data)
+{
+ if (scsi_is_target_device(dev))
+ starget_for_each_device(to_scsi_target(dev), data,
+ device_unblock);
+ return 0;
+}
+
+void
+scsi_target_unblock(struct device *dev, enum scsi_device_state new_state)
+{
+ if (scsi_is_target_device(dev))
+ starget_for_each_device(to_scsi_target(dev), &new_state,
+ device_unblock);
+ else
+ device_for_each_child(dev, &new_state, target_unblock);
+}
+EXPORT_SYMBOL_GPL(scsi_target_unblock);
+
+/**
+ * scsi_kmap_atomic_sg - find and atomically map an sg-elemnt
+ * @sgl: scatter-gather list
+ * @sg_count: number of segments in sg
+ * @offset: offset in bytes into sg, on return offset into the mapped area
+ * @len: bytes to map, on return number of bytes mapped
+ *
+ * Returns virtual address of the start of the mapped page
+ */
+void *scsi_kmap_atomic_sg(struct scatterlist *sgl, int sg_count,
+ size_t *offset, size_t *len)
+{
+ int i;
+ size_t sg_len = 0, len_complete = 0;
+ struct scatterlist *sg;
+ struct page *page;
+
+ WARN_ON(!irqs_disabled());
+
+ for_each_sg(sgl, sg, sg_count, i) {
+ len_complete = sg_len; /* Complete sg-entries */
+ sg_len += sg->length;
+ if (sg_len > *offset)
+ break;
+ }
+
+ if (unlikely(i == sg_count)) {
+ printk(KERN_ERR "%s: Bytes in sg: %zu, requested offset %zu, "
+ "elements %d\n",
+ __func__, sg_len, *offset, sg_count);
+ WARN_ON(1);
+ return NULL;
+ }
+
+ /* Offset starting from the beginning of first page in this sg-entry */
+ *offset = *offset - len_complete + sg->offset;
+
+ /* Assumption: contiguous pages can be accessed as "page + i" */
+ page = nth_page(sg_page(sg), (*offset >> PAGE_SHIFT));
+ *offset &= ~PAGE_MASK;
+
+ /* Bytes in this sg-entry from *offset to the end of the page */
+ sg_len = PAGE_SIZE - *offset;
+ if (*len > sg_len)
+ *len = sg_len;
+
+ return kmap_atomic(page);
+}
+EXPORT_SYMBOL(scsi_kmap_atomic_sg);
+
+/**
+ * scsi_kunmap_atomic_sg - atomically unmap a virtual address, previously mapped with scsi_kmap_atomic_sg
+ * @virt: virtual address to be unmapped
+ */
+void scsi_kunmap_atomic_sg(void *virt)
+{
+ kunmap_atomic(virt);
+}
+EXPORT_SYMBOL(scsi_kunmap_atomic_sg);
+
+void sdev_disable_disk_events(struct scsi_device *sdev)
+{
+ atomic_inc(&sdev->disk_events_disable_depth);
+}
+EXPORT_SYMBOL(sdev_disable_disk_events);
+
+void sdev_enable_disk_events(struct scsi_device *sdev)
+{
+ if (WARN_ON_ONCE(atomic_read(&sdev->disk_events_disable_depth) <= 0))
+ return;
+ atomic_dec(&sdev->disk_events_disable_depth);
+}
+EXPORT_SYMBOL(sdev_enable_disk_events);
+
+/**
+ * scsi_vpd_lun_id - return a unique device identification
+ * @sdev: SCSI device
+ * @id: buffer for the identification
+ * @id_len: length of the buffer
+ *
+ * Copies a unique device identification into @id based
+ * on the information in the VPD page 0x83 of the device.
+ * The string will be formatted as a SCSI name string.
+ *
+ * Returns the length of the identification or error on failure.
+ * If the identifier is longer than the supplied buffer the actual
+ * identifier length is returned and the buffer is not zero-padded.
+ */
+int scsi_vpd_lun_id(struct scsi_device *sdev, char *id, size_t id_len)
+{
+ u8 cur_id_type = 0xff;
+ u8 cur_id_size = 0;
+ const unsigned char *d, *cur_id_str;
+ const struct scsi_vpd *vpd_pg83;
+ int id_size = -EINVAL;
+
+ rcu_read_lock();
+ vpd_pg83 = rcu_dereference(sdev->vpd_pg83);
+ if (!vpd_pg83) {
+ rcu_read_unlock();
+ return -ENXIO;
+ }
+
+ /*
+ * Look for the correct descriptor.
+ * Order of preference for lun descriptor:
+ * - SCSI name string
+ * - NAA IEEE Registered Extended
+ * - EUI-64 based 16-byte
+ * - EUI-64 based 12-byte
+ * - NAA IEEE Registered
+ * - NAA IEEE Extended
+ * - T10 Vendor ID
+ * as longer descriptors reduce the likelyhood
+ * of identification clashes.
+ */
+
+ /* The id string must be at least 20 bytes + terminating NULL byte */
+ if (id_len < 21) {
+ rcu_read_unlock();
+ return -EINVAL;
+ }
+
+ memset(id, 0, id_len);
+ d = vpd_pg83->data + 4;
+ while (d < vpd_pg83->data + vpd_pg83->len) {
+ /* Skip designators not referring to the LUN */
+ if ((d[1] & 0x30) != 0x00)
+ goto next_desig;
+
+ switch (d[1] & 0xf) {
+ case 0x1:
+ /* T10 Vendor ID */
+ if (cur_id_size > d[3])
+ break;
+ /* Prefer anything */
+ if (cur_id_type > 0x01 && cur_id_type != 0xff)
+ break;
+ cur_id_size = d[3];
+ if (cur_id_size + 4 > id_len)
+ cur_id_size = id_len - 4;
+ cur_id_str = d + 4;
+ cur_id_type = d[1] & 0xf;
+ id_size = snprintf(id, id_len, "t10.%*pE",
+ cur_id_size, cur_id_str);
+ break;
+ case 0x2:
+ /* EUI-64 */
+ if (cur_id_size > d[3])
+ break;
+ /* Prefer NAA IEEE Registered Extended */
+ if (cur_id_type == 0x3 &&
+ cur_id_size == d[3])
+ break;
+ cur_id_size = d[3];
+ cur_id_str = d + 4;
+ cur_id_type = d[1] & 0xf;
+ switch (cur_id_size) {
+ case 8:
+ id_size = snprintf(id, id_len,
+ "eui.%8phN",
+ cur_id_str);
+ break;
+ case 12:
+ id_size = snprintf(id, id_len,
+ "eui.%12phN",
+ cur_id_str);
+ break;
+ case 16:
+ id_size = snprintf(id, id_len,
+ "eui.%16phN",
+ cur_id_str);
+ break;
+ default:
+ cur_id_size = 0;
+ break;
+ }
+ break;
+ case 0x3:
+ /* NAA */
+ if (cur_id_size > d[3])
+ break;
+ cur_id_size = d[3];
+ cur_id_str = d + 4;
+ cur_id_type = d[1] & 0xf;
+ switch (cur_id_size) {
+ case 8:
+ id_size = snprintf(id, id_len,
+ "naa.%8phN",
+ cur_id_str);
+ break;
+ case 16:
+ id_size = snprintf(id, id_len,
+ "naa.%16phN",
+ cur_id_str);
+ break;
+ default:
+ cur_id_size = 0;
+ break;
+ }
+ break;
+ case 0x8:
+ /* SCSI name string */
+ if (cur_id_size + 4 > d[3])
+ break;
+ /* Prefer others for truncated descriptor */
+ if (cur_id_size && d[3] > id_len)
+ break;
+ cur_id_size = id_size = d[3];
+ cur_id_str = d + 4;
+ cur_id_type = d[1] & 0xf;
+ if (cur_id_size >= id_len)
+ cur_id_size = id_len - 1;
+ memcpy(id, cur_id_str, cur_id_size);
+ /* Decrease priority for truncated descriptor */
+ if (cur_id_size != id_size)
+ cur_id_size = 6;
+ break;
+ default:
+ break;
+ }
+next_desig:
+ d += d[3] + 4;
+ }
+ rcu_read_unlock();
+
+ return id_size;
+}
+EXPORT_SYMBOL(scsi_vpd_lun_id);
+
+/*
+ * scsi_vpd_tpg_id - return a target port group identifier
+ * @sdev: SCSI device
+ *
+ * Returns the Target Port Group identifier from the information
+ * froom VPD page 0x83 of the device.
+ *
+ * Returns the identifier or error on failure.
+ */
+int scsi_vpd_tpg_id(struct scsi_device *sdev, int *rel_id)
+{
+ const unsigned char *d;
+ const struct scsi_vpd *vpd_pg83;
+ int group_id = -EAGAIN, rel_port = -1;
+
+ rcu_read_lock();
+ vpd_pg83 = rcu_dereference(sdev->vpd_pg83);
+ if (!vpd_pg83) {
+ rcu_read_unlock();
+ return -ENXIO;
+ }
+
+ d = vpd_pg83->data + 4;
+ while (d < vpd_pg83->data + vpd_pg83->len) {
+ switch (d[1] & 0xf) {
+ case 0x4:
+ /* Relative target port */
+ rel_port = get_unaligned_be16(&d[6]);
+ break;
+ case 0x5:
+ /* Target port group */
+ group_id = get_unaligned_be16(&d[6]);
+ break;
+ default:
+ break;
+ }
+ d += d[3] + 4;
+ }
+ rcu_read_unlock();
+
+ if (group_id >= 0 && rel_id && rel_port != -1)
+ *rel_id = rel_port;
+
+ return group_id;
+}
+EXPORT_SYMBOL(scsi_vpd_tpg_id);