v4.19.13 snapshot.
diff --git a/drivers/nvme/host/multipath.c b/drivers/nvme/host/multipath.c
new file mode 100644
index 0000000..c27af27
--- /dev/null
+++ b/drivers/nvme/host/multipath.c
@@ -0,0 +1,567 @@
+/*
+ * Copyright (c) 2017-2018 Christoph Hellwig.
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms and conditions of the GNU General Public License,
+ * version 2, as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
+ * more details.
+ */
+
+#include <linux/moduleparam.h>
+#include <trace/events/block.h>
+#include "nvme.h"
+
+static bool multipath = true;
+module_param(multipath, bool, 0444);
+MODULE_PARM_DESC(multipath,
+ "turn on native support for multiple controllers per subsystem");
+
+inline bool nvme_ctrl_use_ana(struct nvme_ctrl *ctrl)
+{
+ return multipath && ctrl->subsys && (ctrl->subsys->cmic & (1 << 3));
+}
+
+/*
+ * If multipathing is enabled we need to always use the subsystem instance
+ * number for numbering our devices to avoid conflicts between subsystems that
+ * have multiple controllers and thus use the multipath-aware subsystem node
+ * and those that have a single controller and use the controller node
+ * directly.
+ */
+void nvme_set_disk_name(char *disk_name, struct nvme_ns *ns,
+ struct nvme_ctrl *ctrl, int *flags)
+{
+ if (!multipath) {
+ sprintf(disk_name, "nvme%dn%d", ctrl->instance, ns->head->instance);
+ } else if (ns->head->disk) {
+ sprintf(disk_name, "nvme%dc%dn%d", ctrl->subsys->instance,
+ ctrl->cntlid, ns->head->instance);
+ *flags = GENHD_FL_HIDDEN;
+ } else {
+ sprintf(disk_name, "nvme%dn%d", ctrl->subsys->instance,
+ ns->head->instance);
+ }
+}
+
+void nvme_failover_req(struct request *req)
+{
+ struct nvme_ns *ns = req->q->queuedata;
+ u16 status = nvme_req(req)->status;
+ unsigned long flags;
+
+ spin_lock_irqsave(&ns->head->requeue_lock, flags);
+ blk_steal_bios(&ns->head->requeue_list, req);
+ spin_unlock_irqrestore(&ns->head->requeue_lock, flags);
+ blk_mq_end_request(req, 0);
+
+ switch (status & 0x7ff) {
+ case NVME_SC_ANA_TRANSITION:
+ case NVME_SC_ANA_INACCESSIBLE:
+ case NVME_SC_ANA_PERSISTENT_LOSS:
+ /*
+ * If we got back an ANA error we know the controller is alive,
+ * but not ready to serve this namespaces. The spec suggests
+ * we should update our general state here, but due to the fact
+ * that the admin and I/O queues are not serialized that is
+ * fundamentally racy. So instead just clear the current path,
+ * mark the the path as pending and kick of a re-read of the ANA
+ * log page ASAP.
+ */
+ nvme_mpath_clear_current_path(ns);
+ if (ns->ctrl->ana_log_buf) {
+ set_bit(NVME_NS_ANA_PENDING, &ns->flags);
+ queue_work(nvme_wq, &ns->ctrl->ana_work);
+ }
+ break;
+ case NVME_SC_HOST_PATH_ERROR:
+ /*
+ * Temporary transport disruption in talking to the controller.
+ * Try to send on a new path.
+ */
+ nvme_mpath_clear_current_path(ns);
+ break;
+ default:
+ /*
+ * Reset the controller for any non-ANA error as we don't know
+ * what caused the error.
+ */
+ nvme_reset_ctrl(ns->ctrl);
+ break;
+ }
+
+ kblockd_schedule_work(&ns->head->requeue_work);
+}
+
+void nvme_kick_requeue_lists(struct nvme_ctrl *ctrl)
+{
+ struct nvme_ns *ns;
+
+ down_read(&ctrl->namespaces_rwsem);
+ list_for_each_entry(ns, &ctrl->namespaces, list) {
+ if (ns->head->disk)
+ kblockd_schedule_work(&ns->head->requeue_work);
+ }
+ up_read(&ctrl->namespaces_rwsem);
+}
+
+static const char *nvme_ana_state_names[] = {
+ [0] = "invalid state",
+ [NVME_ANA_OPTIMIZED] = "optimized",
+ [NVME_ANA_NONOPTIMIZED] = "non-optimized",
+ [NVME_ANA_INACCESSIBLE] = "inaccessible",
+ [NVME_ANA_PERSISTENT_LOSS] = "persistent-loss",
+ [NVME_ANA_CHANGE] = "change",
+};
+
+static struct nvme_ns *__nvme_find_path(struct nvme_ns_head *head)
+{
+ struct nvme_ns *ns, *fallback = NULL;
+
+ list_for_each_entry_rcu(ns, &head->list, siblings) {
+ if (ns->ctrl->state != NVME_CTRL_LIVE ||
+ test_bit(NVME_NS_ANA_PENDING, &ns->flags))
+ continue;
+ switch (ns->ana_state) {
+ case NVME_ANA_OPTIMIZED:
+ rcu_assign_pointer(head->current_path, ns);
+ return ns;
+ case NVME_ANA_NONOPTIMIZED:
+ fallback = ns;
+ break;
+ default:
+ break;
+ }
+ }
+
+ if (fallback)
+ rcu_assign_pointer(head->current_path, fallback);
+ return fallback;
+}
+
+static inline bool nvme_path_is_optimized(struct nvme_ns *ns)
+{
+ return ns->ctrl->state == NVME_CTRL_LIVE &&
+ ns->ana_state == NVME_ANA_OPTIMIZED;
+}
+
+inline struct nvme_ns *nvme_find_path(struct nvme_ns_head *head)
+{
+ struct nvme_ns *ns = srcu_dereference(head->current_path, &head->srcu);
+
+ if (unlikely(!ns || !nvme_path_is_optimized(ns)))
+ ns = __nvme_find_path(head);
+ return ns;
+}
+
+static blk_qc_t nvme_ns_head_make_request(struct request_queue *q,
+ struct bio *bio)
+{
+ struct nvme_ns_head *head = q->queuedata;
+ struct device *dev = disk_to_dev(head->disk);
+ struct nvme_ns *ns;
+ blk_qc_t ret = BLK_QC_T_NONE;
+ int srcu_idx;
+
+ srcu_idx = srcu_read_lock(&head->srcu);
+ ns = nvme_find_path(head);
+ if (likely(ns)) {
+ bio->bi_disk = ns->disk;
+ bio->bi_opf |= REQ_NVME_MPATH;
+ trace_block_bio_remap(bio->bi_disk->queue, bio,
+ disk_devt(ns->head->disk),
+ bio->bi_iter.bi_sector);
+ ret = direct_make_request(bio);
+ } else if (!list_empty_careful(&head->list)) {
+ dev_warn_ratelimited(dev, "no path available - requeuing I/O\n");
+
+ spin_lock_irq(&head->requeue_lock);
+ bio_list_add(&head->requeue_list, bio);
+ spin_unlock_irq(&head->requeue_lock);
+ } else {
+ dev_warn_ratelimited(dev, "no path - failing I/O\n");
+
+ bio->bi_status = BLK_STS_IOERR;
+ bio_endio(bio);
+ }
+
+ srcu_read_unlock(&head->srcu, srcu_idx);
+ return ret;
+}
+
+static bool nvme_ns_head_poll(struct request_queue *q, blk_qc_t qc)
+{
+ struct nvme_ns_head *head = q->queuedata;
+ struct nvme_ns *ns;
+ bool found = false;
+ int srcu_idx;
+
+ srcu_idx = srcu_read_lock(&head->srcu);
+ ns = srcu_dereference(head->current_path, &head->srcu);
+ if (likely(ns && nvme_path_is_optimized(ns)))
+ found = ns->queue->poll_fn(q, qc);
+ srcu_read_unlock(&head->srcu, srcu_idx);
+ return found;
+}
+
+static void nvme_requeue_work(struct work_struct *work)
+{
+ struct nvme_ns_head *head =
+ container_of(work, struct nvme_ns_head, requeue_work);
+ struct bio *bio, *next;
+
+ spin_lock_irq(&head->requeue_lock);
+ next = bio_list_get(&head->requeue_list);
+ spin_unlock_irq(&head->requeue_lock);
+
+ while ((bio = next) != NULL) {
+ next = bio->bi_next;
+ bio->bi_next = NULL;
+
+ /*
+ * Reset disk to the mpath node and resubmit to select a new
+ * path.
+ */
+ bio->bi_disk = head->disk;
+ generic_make_request(bio);
+ }
+}
+
+int nvme_mpath_alloc_disk(struct nvme_ctrl *ctrl, struct nvme_ns_head *head)
+{
+ struct request_queue *q;
+ bool vwc = false;
+
+ mutex_init(&head->lock);
+ bio_list_init(&head->requeue_list);
+ spin_lock_init(&head->requeue_lock);
+ INIT_WORK(&head->requeue_work, nvme_requeue_work);
+
+ /*
+ * Add a multipath node if the subsystems supports multiple controllers.
+ * We also do this for private namespaces as the namespace sharing data could
+ * change after a rescan.
+ */
+ if (!(ctrl->subsys->cmic & (1 << 1)) || !multipath)
+ return 0;
+
+ q = blk_alloc_queue_node(GFP_KERNEL, NUMA_NO_NODE, NULL);
+ if (!q)
+ goto out;
+ q->queuedata = head;
+ blk_queue_make_request(q, nvme_ns_head_make_request);
+ q->poll_fn = nvme_ns_head_poll;
+ blk_queue_flag_set(QUEUE_FLAG_NONROT, q);
+ /* set to a default value for 512 until disk is validated */
+ blk_queue_logical_block_size(q, 512);
+ blk_set_stacking_limits(&q->limits);
+
+ /* we need to propagate up the VMC settings */
+ if (ctrl->vwc & NVME_CTRL_VWC_PRESENT)
+ vwc = true;
+ blk_queue_write_cache(q, vwc, vwc);
+
+ head->disk = alloc_disk(0);
+ if (!head->disk)
+ goto out_cleanup_queue;
+ head->disk->fops = &nvme_ns_head_ops;
+ head->disk->private_data = head;
+ head->disk->queue = q;
+ head->disk->flags = GENHD_FL_EXT_DEVT;
+ sprintf(head->disk->disk_name, "nvme%dn%d",
+ ctrl->subsys->instance, head->instance);
+ return 0;
+
+out_cleanup_queue:
+ blk_cleanup_queue(q);
+out:
+ return -ENOMEM;
+}
+
+static void nvme_mpath_set_live(struct nvme_ns *ns)
+{
+ struct nvme_ns_head *head = ns->head;
+
+ lockdep_assert_held(&ns->head->lock);
+
+ if (!head->disk)
+ return;
+
+ if (!(head->disk->flags & GENHD_FL_UP)) {
+ device_add_disk(&head->subsys->dev, head->disk);
+ if (sysfs_create_group(&disk_to_dev(head->disk)->kobj,
+ &nvme_ns_id_attr_group))
+ dev_warn(&head->subsys->dev,
+ "failed to create id group.\n");
+ }
+
+ kblockd_schedule_work(&ns->head->requeue_work);
+}
+
+static int nvme_parse_ana_log(struct nvme_ctrl *ctrl, void *data,
+ int (*cb)(struct nvme_ctrl *ctrl, struct nvme_ana_group_desc *,
+ void *))
+{
+ void *base = ctrl->ana_log_buf;
+ size_t offset = sizeof(struct nvme_ana_rsp_hdr);
+ int error, i;
+
+ lockdep_assert_held(&ctrl->ana_lock);
+
+ for (i = 0; i < le16_to_cpu(ctrl->ana_log_buf->ngrps); i++) {
+ struct nvme_ana_group_desc *desc = base + offset;
+ u32 nr_nsids = le32_to_cpu(desc->nnsids);
+ size_t nsid_buf_size = nr_nsids * sizeof(__le32);
+
+ if (WARN_ON_ONCE(desc->grpid == 0))
+ return -EINVAL;
+ if (WARN_ON_ONCE(le32_to_cpu(desc->grpid) > ctrl->anagrpmax))
+ return -EINVAL;
+ if (WARN_ON_ONCE(desc->state == 0))
+ return -EINVAL;
+ if (WARN_ON_ONCE(desc->state > NVME_ANA_CHANGE))
+ return -EINVAL;
+
+ offset += sizeof(*desc);
+ if (WARN_ON_ONCE(offset > ctrl->ana_log_size - nsid_buf_size))
+ return -EINVAL;
+
+ error = cb(ctrl, desc, data);
+ if (error)
+ return error;
+
+ offset += nsid_buf_size;
+ if (WARN_ON_ONCE(offset > ctrl->ana_log_size - sizeof(*desc)))
+ return -EINVAL;
+ }
+
+ return 0;
+}
+
+static inline bool nvme_state_is_live(enum nvme_ana_state state)
+{
+ return state == NVME_ANA_OPTIMIZED || state == NVME_ANA_NONOPTIMIZED;
+}
+
+static void nvme_update_ns_ana_state(struct nvme_ana_group_desc *desc,
+ struct nvme_ns *ns)
+{
+ enum nvme_ana_state old;
+
+ mutex_lock(&ns->head->lock);
+ old = ns->ana_state;
+ ns->ana_grpid = le32_to_cpu(desc->grpid);
+ ns->ana_state = desc->state;
+ clear_bit(NVME_NS_ANA_PENDING, &ns->flags);
+
+ if (nvme_state_is_live(ns->ana_state) && !nvme_state_is_live(old))
+ nvme_mpath_set_live(ns);
+ mutex_unlock(&ns->head->lock);
+}
+
+static int nvme_update_ana_state(struct nvme_ctrl *ctrl,
+ struct nvme_ana_group_desc *desc, void *data)
+{
+ u32 nr_nsids = le32_to_cpu(desc->nnsids), n = 0;
+ unsigned *nr_change_groups = data;
+ struct nvme_ns *ns;
+
+ dev_info(ctrl->device, "ANA group %d: %s.\n",
+ le32_to_cpu(desc->grpid),
+ nvme_ana_state_names[desc->state]);
+
+ if (desc->state == NVME_ANA_CHANGE)
+ (*nr_change_groups)++;
+
+ if (!nr_nsids)
+ return 0;
+
+ down_write(&ctrl->namespaces_rwsem);
+ list_for_each_entry(ns, &ctrl->namespaces, list) {
+ if (ns->head->ns_id != le32_to_cpu(desc->nsids[n]))
+ continue;
+ nvme_update_ns_ana_state(desc, ns);
+ if (++n == nr_nsids)
+ break;
+ }
+ up_write(&ctrl->namespaces_rwsem);
+ WARN_ON_ONCE(n < nr_nsids);
+ return 0;
+}
+
+static int nvme_read_ana_log(struct nvme_ctrl *ctrl, bool groups_only)
+{
+ u32 nr_change_groups = 0;
+ int error;
+
+ mutex_lock(&ctrl->ana_lock);
+ error = nvme_get_log(ctrl, NVME_NSID_ALL, NVME_LOG_ANA,
+ groups_only ? NVME_ANA_LOG_RGO : 0,
+ ctrl->ana_log_buf, ctrl->ana_log_size, 0);
+ if (error) {
+ dev_warn(ctrl->device, "Failed to get ANA log: %d\n", error);
+ goto out_unlock;
+ }
+
+ error = nvme_parse_ana_log(ctrl, &nr_change_groups,
+ nvme_update_ana_state);
+ if (error)
+ goto out_unlock;
+
+ /*
+ * In theory we should have an ANATT timer per group as they might enter
+ * the change state at different times. But that is a lot of overhead
+ * just to protect against a target that keeps entering new changes
+ * states while never finishing previous ones. But we'll still
+ * eventually time out once all groups are in change state, so this
+ * isn't a big deal.
+ *
+ * We also double the ANATT value to provide some slack for transports
+ * or AEN processing overhead.
+ */
+ if (nr_change_groups)
+ mod_timer(&ctrl->anatt_timer, ctrl->anatt * HZ * 2 + jiffies);
+ else
+ del_timer_sync(&ctrl->anatt_timer);
+out_unlock:
+ mutex_unlock(&ctrl->ana_lock);
+ return error;
+}
+
+static void nvme_ana_work(struct work_struct *work)
+{
+ struct nvme_ctrl *ctrl = container_of(work, struct nvme_ctrl, ana_work);
+
+ nvme_read_ana_log(ctrl, false);
+}
+
+static void nvme_anatt_timeout(struct timer_list *t)
+{
+ struct nvme_ctrl *ctrl = from_timer(ctrl, t, anatt_timer);
+
+ dev_info(ctrl->device, "ANATT timeout, resetting controller.\n");
+ nvme_reset_ctrl(ctrl);
+}
+
+void nvme_mpath_stop(struct nvme_ctrl *ctrl)
+{
+ if (!nvme_ctrl_use_ana(ctrl))
+ return;
+ del_timer_sync(&ctrl->anatt_timer);
+ cancel_work_sync(&ctrl->ana_work);
+}
+
+static ssize_t ana_grpid_show(struct device *dev, struct device_attribute *attr,
+ char *buf)
+{
+ return sprintf(buf, "%d\n", nvme_get_ns_from_dev(dev)->ana_grpid);
+}
+DEVICE_ATTR_RO(ana_grpid);
+
+static ssize_t ana_state_show(struct device *dev, struct device_attribute *attr,
+ char *buf)
+{
+ struct nvme_ns *ns = nvme_get_ns_from_dev(dev);
+
+ return sprintf(buf, "%s\n", nvme_ana_state_names[ns->ana_state]);
+}
+DEVICE_ATTR_RO(ana_state);
+
+static int nvme_set_ns_ana_state(struct nvme_ctrl *ctrl,
+ struct nvme_ana_group_desc *desc, void *data)
+{
+ struct nvme_ns *ns = data;
+
+ if (ns->ana_grpid == le32_to_cpu(desc->grpid)) {
+ nvme_update_ns_ana_state(desc, ns);
+ return -ENXIO; /* just break out of the loop */
+ }
+
+ return 0;
+}
+
+void nvme_mpath_add_disk(struct nvme_ns *ns, struct nvme_id_ns *id)
+{
+ if (nvme_ctrl_use_ana(ns->ctrl)) {
+ mutex_lock(&ns->ctrl->ana_lock);
+ ns->ana_grpid = le32_to_cpu(id->anagrpid);
+ nvme_parse_ana_log(ns->ctrl, ns, nvme_set_ns_ana_state);
+ mutex_unlock(&ns->ctrl->ana_lock);
+ } else {
+ mutex_lock(&ns->head->lock);
+ ns->ana_state = NVME_ANA_OPTIMIZED;
+ nvme_mpath_set_live(ns);
+ mutex_unlock(&ns->head->lock);
+ }
+}
+
+void nvme_mpath_remove_disk(struct nvme_ns_head *head)
+{
+ if (!head->disk)
+ return;
+ if (head->disk->flags & GENHD_FL_UP) {
+ sysfs_remove_group(&disk_to_dev(head->disk)->kobj,
+ &nvme_ns_id_attr_group);
+ del_gendisk(head->disk);
+ }
+ blk_set_queue_dying(head->disk->queue);
+ /* make sure all pending bios are cleaned up */
+ kblockd_schedule_work(&head->requeue_work);
+ flush_work(&head->requeue_work);
+ blk_cleanup_queue(head->disk->queue);
+ put_disk(head->disk);
+}
+
+int nvme_mpath_init(struct nvme_ctrl *ctrl, struct nvme_id_ctrl *id)
+{
+ int error;
+
+ if (!nvme_ctrl_use_ana(ctrl))
+ return 0;
+
+ ctrl->anacap = id->anacap;
+ ctrl->anatt = id->anatt;
+ ctrl->nanagrpid = le32_to_cpu(id->nanagrpid);
+ ctrl->anagrpmax = le32_to_cpu(id->anagrpmax);
+
+ mutex_init(&ctrl->ana_lock);
+ timer_setup(&ctrl->anatt_timer, nvme_anatt_timeout, 0);
+ ctrl->ana_log_size = sizeof(struct nvme_ana_rsp_hdr) +
+ ctrl->nanagrpid * sizeof(struct nvme_ana_group_desc);
+ if (!(ctrl->anacap & (1 << 6)))
+ ctrl->ana_log_size += ctrl->max_namespaces * sizeof(__le32);
+
+ if (ctrl->ana_log_size > ctrl->max_hw_sectors << SECTOR_SHIFT) {
+ dev_err(ctrl->device,
+ "ANA log page size (%zd) larger than MDTS (%d).\n",
+ ctrl->ana_log_size,
+ ctrl->max_hw_sectors << SECTOR_SHIFT);
+ dev_err(ctrl->device, "disabling ANA support.\n");
+ return 0;
+ }
+
+ INIT_WORK(&ctrl->ana_work, nvme_ana_work);
+ ctrl->ana_log_buf = kmalloc(ctrl->ana_log_size, GFP_KERNEL);
+ if (!ctrl->ana_log_buf) {
+ error = -ENOMEM;
+ goto out;
+ }
+
+ error = nvme_read_ana_log(ctrl, true);
+ if (error)
+ goto out_free_ana_log_buf;
+ return 0;
+out_free_ana_log_buf:
+ kfree(ctrl->ana_log_buf);
+out:
+ return error;
+}
+
+void nvme_mpath_uninit(struct nvme_ctrl *ctrl)
+{
+ kfree(ctrl->ana_log_buf);
+}
+