v4.19.13 snapshot.
diff --git a/drivers/md/dm-io.c b/drivers/md/dm-io.c
new file mode 100644
index 0000000..81ffc59
--- /dev/null
+++ b/drivers/md/dm-io.c
@@ -0,0 +1,571 @@
+/*
+ * Copyright (C) 2003 Sistina Software
+ * Copyright (C) 2006 Red Hat GmbH
+ *
+ * This file is released under the GPL.
+ */
+
+#include "dm-core.h"
+
+#include <linux/device-mapper.h>
+
+#include <linux/bio.h>
+#include <linux/completion.h>
+#include <linux/mempool.h>
+#include <linux/module.h>
+#include <linux/sched.h>
+#include <linux/slab.h>
+#include <linux/dm-io.h>
+
+#define DM_MSG_PREFIX "io"
+
+#define DM_IO_MAX_REGIONS BITS_PER_LONG
+
+struct dm_io_client {
+ mempool_t pool;
+ struct bio_set bios;
+};
+
+/*
+ * Aligning 'struct io' reduces the number of bits required to store
+ * its address. Refer to store_io_and_region_in_bio() below.
+ */
+struct io {
+ unsigned long error_bits;
+ atomic_t count;
+ struct dm_io_client *client;
+ io_notify_fn callback;
+ void *context;
+ void *vma_invalidate_address;
+ unsigned long vma_invalidate_size;
+} __attribute__((aligned(DM_IO_MAX_REGIONS)));
+
+static struct kmem_cache *_dm_io_cache;
+
+/*
+ * Create a client with mempool and bioset.
+ */
+struct dm_io_client *dm_io_client_create(void)
+{
+ struct dm_io_client *client;
+ unsigned min_ios = dm_get_reserved_bio_based_ios();
+ int ret;
+
+ client = kzalloc(sizeof(*client), GFP_KERNEL);
+ if (!client)
+ return ERR_PTR(-ENOMEM);
+
+ ret = mempool_init_slab_pool(&client->pool, min_ios, _dm_io_cache);
+ if (ret)
+ goto bad;
+
+ ret = bioset_init(&client->bios, min_ios, 0, BIOSET_NEED_BVECS);
+ if (ret)
+ goto bad;
+
+ return client;
+
+ bad:
+ mempool_exit(&client->pool);
+ kfree(client);
+ return ERR_PTR(ret);
+}
+EXPORT_SYMBOL(dm_io_client_create);
+
+void dm_io_client_destroy(struct dm_io_client *client)
+{
+ mempool_exit(&client->pool);
+ bioset_exit(&client->bios);
+ kfree(client);
+}
+EXPORT_SYMBOL(dm_io_client_destroy);
+
+/*-----------------------------------------------------------------
+ * We need to keep track of which region a bio is doing io for.
+ * To avoid a memory allocation to store just 5 or 6 bits, we
+ * ensure the 'struct io' pointer is aligned so enough low bits are
+ * always zero and then combine it with the region number directly in
+ * bi_private.
+ *---------------------------------------------------------------*/
+static void store_io_and_region_in_bio(struct bio *bio, struct io *io,
+ unsigned region)
+{
+ if (unlikely(!IS_ALIGNED((unsigned long)io, DM_IO_MAX_REGIONS))) {
+ DMCRIT("Unaligned struct io pointer %p", io);
+ BUG();
+ }
+
+ bio->bi_private = (void *)((unsigned long)io | region);
+}
+
+static void retrieve_io_and_region_from_bio(struct bio *bio, struct io **io,
+ unsigned *region)
+{
+ unsigned long val = (unsigned long)bio->bi_private;
+
+ *io = (void *)(val & -(unsigned long)DM_IO_MAX_REGIONS);
+ *region = val & (DM_IO_MAX_REGIONS - 1);
+}
+
+/*-----------------------------------------------------------------
+ * We need an io object to keep track of the number of bios that
+ * have been dispatched for a particular io.
+ *---------------------------------------------------------------*/
+static void complete_io(struct io *io)
+{
+ unsigned long error_bits = io->error_bits;
+ io_notify_fn fn = io->callback;
+ void *context = io->context;
+
+ if (io->vma_invalidate_size)
+ invalidate_kernel_vmap_range(io->vma_invalidate_address,
+ io->vma_invalidate_size);
+
+ mempool_free(io, &io->client->pool);
+ fn(error_bits, context);
+}
+
+static void dec_count(struct io *io, unsigned int region, blk_status_t error)
+{
+ if (error)
+ set_bit(region, &io->error_bits);
+
+ if (atomic_dec_and_test(&io->count))
+ complete_io(io);
+}
+
+static void endio(struct bio *bio)
+{
+ struct io *io;
+ unsigned region;
+ blk_status_t error;
+
+ if (bio->bi_status && bio_data_dir(bio) == READ)
+ zero_fill_bio(bio);
+
+ /*
+ * The bio destructor in bio_put() may use the io object.
+ */
+ retrieve_io_and_region_from_bio(bio, &io, ®ion);
+
+ error = bio->bi_status;
+ bio_put(bio);
+
+ dec_count(io, region, error);
+}
+
+/*-----------------------------------------------------------------
+ * These little objects provide an abstraction for getting a new
+ * destination page for io.
+ *---------------------------------------------------------------*/
+struct dpages {
+ void (*get_page)(struct dpages *dp,
+ struct page **p, unsigned long *len, unsigned *offset);
+ void (*next_page)(struct dpages *dp);
+
+ union {
+ unsigned context_u;
+ struct bvec_iter context_bi;
+ };
+ void *context_ptr;
+
+ void *vma_invalidate_address;
+ unsigned long vma_invalidate_size;
+};
+
+/*
+ * Functions for getting the pages from a list.
+ */
+static void list_get_page(struct dpages *dp,
+ struct page **p, unsigned long *len, unsigned *offset)
+{
+ unsigned o = dp->context_u;
+ struct page_list *pl = (struct page_list *) dp->context_ptr;
+
+ *p = pl->page;
+ *len = PAGE_SIZE - o;
+ *offset = o;
+}
+
+static void list_next_page(struct dpages *dp)
+{
+ struct page_list *pl = (struct page_list *) dp->context_ptr;
+ dp->context_ptr = pl->next;
+ dp->context_u = 0;
+}
+
+static void list_dp_init(struct dpages *dp, struct page_list *pl, unsigned offset)
+{
+ dp->get_page = list_get_page;
+ dp->next_page = list_next_page;
+ dp->context_u = offset;
+ dp->context_ptr = pl;
+}
+
+/*
+ * Functions for getting the pages from a bvec.
+ */
+static void bio_get_page(struct dpages *dp, struct page **p,
+ unsigned long *len, unsigned *offset)
+{
+ struct bio_vec bvec = bvec_iter_bvec((struct bio_vec *)dp->context_ptr,
+ dp->context_bi);
+
+ *p = bvec.bv_page;
+ *len = bvec.bv_len;
+ *offset = bvec.bv_offset;
+
+ /* avoid figuring it out again in bio_next_page() */
+ dp->context_bi.bi_sector = (sector_t)bvec.bv_len;
+}
+
+static void bio_next_page(struct dpages *dp)
+{
+ unsigned int len = (unsigned int)dp->context_bi.bi_sector;
+
+ bvec_iter_advance((struct bio_vec *)dp->context_ptr,
+ &dp->context_bi, len);
+}
+
+static void bio_dp_init(struct dpages *dp, struct bio *bio)
+{
+ dp->get_page = bio_get_page;
+ dp->next_page = bio_next_page;
+
+ /*
+ * We just use bvec iterator to retrieve pages, so it is ok to
+ * access the bvec table directly here
+ */
+ dp->context_ptr = bio->bi_io_vec;
+ dp->context_bi = bio->bi_iter;
+}
+
+/*
+ * Functions for getting the pages from a VMA.
+ */
+static void vm_get_page(struct dpages *dp,
+ struct page **p, unsigned long *len, unsigned *offset)
+{
+ *p = vmalloc_to_page(dp->context_ptr);
+ *offset = dp->context_u;
+ *len = PAGE_SIZE - dp->context_u;
+}
+
+static void vm_next_page(struct dpages *dp)
+{
+ dp->context_ptr += PAGE_SIZE - dp->context_u;
+ dp->context_u = 0;
+}
+
+static void vm_dp_init(struct dpages *dp, void *data)
+{
+ dp->get_page = vm_get_page;
+ dp->next_page = vm_next_page;
+ dp->context_u = offset_in_page(data);
+ dp->context_ptr = data;
+}
+
+/*
+ * Functions for getting the pages from kernel memory.
+ */
+static void km_get_page(struct dpages *dp, struct page **p, unsigned long *len,
+ unsigned *offset)
+{
+ *p = virt_to_page(dp->context_ptr);
+ *offset = dp->context_u;
+ *len = PAGE_SIZE - dp->context_u;
+}
+
+static void km_next_page(struct dpages *dp)
+{
+ dp->context_ptr += PAGE_SIZE - dp->context_u;
+ dp->context_u = 0;
+}
+
+static void km_dp_init(struct dpages *dp, void *data)
+{
+ dp->get_page = km_get_page;
+ dp->next_page = km_next_page;
+ dp->context_u = offset_in_page(data);
+ dp->context_ptr = data;
+}
+
+/*-----------------------------------------------------------------
+ * IO routines that accept a list of pages.
+ *---------------------------------------------------------------*/
+static void do_region(int op, int op_flags, unsigned region,
+ struct dm_io_region *where, struct dpages *dp,
+ struct io *io)
+{
+ struct bio *bio;
+ struct page *page;
+ unsigned long len;
+ unsigned offset;
+ unsigned num_bvecs;
+ sector_t remaining = where->count;
+ struct request_queue *q = bdev_get_queue(where->bdev);
+ unsigned short logical_block_size = queue_logical_block_size(q);
+ sector_t num_sectors;
+ unsigned int uninitialized_var(special_cmd_max_sectors);
+
+ /*
+ * Reject unsupported discard and write same requests.
+ */
+ if (op == REQ_OP_DISCARD)
+ special_cmd_max_sectors = q->limits.max_discard_sectors;
+ else if (op == REQ_OP_WRITE_ZEROES)
+ special_cmd_max_sectors = q->limits.max_write_zeroes_sectors;
+ else if (op == REQ_OP_WRITE_SAME)
+ special_cmd_max_sectors = q->limits.max_write_same_sectors;
+ if ((op == REQ_OP_DISCARD || op == REQ_OP_WRITE_ZEROES ||
+ op == REQ_OP_WRITE_SAME) && special_cmd_max_sectors == 0) {
+ atomic_inc(&io->count);
+ dec_count(io, region, BLK_STS_NOTSUPP);
+ return;
+ }
+
+ /*
+ * where->count may be zero if op holds a flush and we need to
+ * send a zero-sized flush.
+ */
+ do {
+ /*
+ * Allocate a suitably sized-bio.
+ */
+ switch (op) {
+ case REQ_OP_DISCARD:
+ case REQ_OP_WRITE_ZEROES:
+ num_bvecs = 0;
+ break;
+ case REQ_OP_WRITE_SAME:
+ num_bvecs = 1;
+ break;
+ default:
+ num_bvecs = min_t(int, BIO_MAX_PAGES,
+ dm_sector_div_up(remaining, (PAGE_SIZE >> SECTOR_SHIFT)));
+ }
+
+ bio = bio_alloc_bioset(GFP_NOIO, num_bvecs, &io->client->bios);
+ bio->bi_iter.bi_sector = where->sector + (where->count - remaining);
+ bio_set_dev(bio, where->bdev);
+ bio->bi_end_io = endio;
+ bio_set_op_attrs(bio, op, op_flags);
+ store_io_and_region_in_bio(bio, io, region);
+
+ if (op == REQ_OP_DISCARD || op == REQ_OP_WRITE_ZEROES) {
+ num_sectors = min_t(sector_t, special_cmd_max_sectors, remaining);
+ bio->bi_iter.bi_size = num_sectors << SECTOR_SHIFT;
+ remaining -= num_sectors;
+ } else if (op == REQ_OP_WRITE_SAME) {
+ /*
+ * WRITE SAME only uses a single page.
+ */
+ dp->get_page(dp, &page, &len, &offset);
+ bio_add_page(bio, page, logical_block_size, offset);
+ num_sectors = min_t(sector_t, special_cmd_max_sectors, remaining);
+ bio->bi_iter.bi_size = num_sectors << SECTOR_SHIFT;
+
+ offset = 0;
+ remaining -= num_sectors;
+ dp->next_page(dp);
+ } else while (remaining) {
+ /*
+ * Try and add as many pages as possible.
+ */
+ dp->get_page(dp, &page, &len, &offset);
+ len = min(len, to_bytes(remaining));
+ if (!bio_add_page(bio, page, len, offset))
+ break;
+
+ offset = 0;
+ remaining -= to_sector(len);
+ dp->next_page(dp);
+ }
+
+ atomic_inc(&io->count);
+ submit_bio(bio);
+ } while (remaining);
+}
+
+static void dispatch_io(int op, int op_flags, unsigned int num_regions,
+ struct dm_io_region *where, struct dpages *dp,
+ struct io *io, int sync)
+{
+ int i;
+ struct dpages old_pages = *dp;
+
+ BUG_ON(num_regions > DM_IO_MAX_REGIONS);
+
+ if (sync)
+ op_flags |= REQ_SYNC;
+
+ /*
+ * For multiple regions we need to be careful to rewind
+ * the dp object for each call to do_region.
+ */
+ for (i = 0; i < num_regions; i++) {
+ *dp = old_pages;
+ if (where[i].count || (op_flags & REQ_PREFLUSH))
+ do_region(op, op_flags, i, where + i, dp, io);
+ }
+
+ /*
+ * Drop the extra reference that we were holding to avoid
+ * the io being completed too early.
+ */
+ dec_count(io, 0, 0);
+}
+
+struct sync_io {
+ unsigned long error_bits;
+ struct completion wait;
+};
+
+static void sync_io_complete(unsigned long error, void *context)
+{
+ struct sync_io *sio = context;
+
+ sio->error_bits = error;
+ complete(&sio->wait);
+}
+
+static int sync_io(struct dm_io_client *client, unsigned int num_regions,
+ struct dm_io_region *where, int op, int op_flags,
+ struct dpages *dp, unsigned long *error_bits)
+{
+ struct io *io;
+ struct sync_io sio;
+
+ if (num_regions > 1 && !op_is_write(op)) {
+ WARN_ON(1);
+ return -EIO;
+ }
+
+ init_completion(&sio.wait);
+
+ io = mempool_alloc(&client->pool, GFP_NOIO);
+ io->error_bits = 0;
+ atomic_set(&io->count, 1); /* see dispatch_io() */
+ io->client = client;
+ io->callback = sync_io_complete;
+ io->context = &sio;
+
+ io->vma_invalidate_address = dp->vma_invalidate_address;
+ io->vma_invalidate_size = dp->vma_invalidate_size;
+
+ dispatch_io(op, op_flags, num_regions, where, dp, io, 1);
+
+ wait_for_completion_io(&sio.wait);
+
+ if (error_bits)
+ *error_bits = sio.error_bits;
+
+ return sio.error_bits ? -EIO : 0;
+}
+
+static int async_io(struct dm_io_client *client, unsigned int num_regions,
+ struct dm_io_region *where, int op, int op_flags,
+ struct dpages *dp, io_notify_fn fn, void *context)
+{
+ struct io *io;
+
+ if (num_regions > 1 && !op_is_write(op)) {
+ WARN_ON(1);
+ fn(1, context);
+ return -EIO;
+ }
+
+ io = mempool_alloc(&client->pool, GFP_NOIO);
+ io->error_bits = 0;
+ atomic_set(&io->count, 1); /* see dispatch_io() */
+ io->client = client;
+ io->callback = fn;
+ io->context = context;
+
+ io->vma_invalidate_address = dp->vma_invalidate_address;
+ io->vma_invalidate_size = dp->vma_invalidate_size;
+
+ dispatch_io(op, op_flags, num_regions, where, dp, io, 0);
+ return 0;
+}
+
+static int dp_init(struct dm_io_request *io_req, struct dpages *dp,
+ unsigned long size)
+{
+ /* Set up dpages based on memory type */
+
+ dp->vma_invalidate_address = NULL;
+ dp->vma_invalidate_size = 0;
+
+ switch (io_req->mem.type) {
+ case DM_IO_PAGE_LIST:
+ list_dp_init(dp, io_req->mem.ptr.pl, io_req->mem.offset);
+ break;
+
+ case DM_IO_BIO:
+ bio_dp_init(dp, io_req->mem.ptr.bio);
+ break;
+
+ case DM_IO_VMA:
+ flush_kernel_vmap_range(io_req->mem.ptr.vma, size);
+ if (io_req->bi_op == REQ_OP_READ) {
+ dp->vma_invalidate_address = io_req->mem.ptr.vma;
+ dp->vma_invalidate_size = size;
+ }
+ vm_dp_init(dp, io_req->mem.ptr.vma);
+ break;
+
+ case DM_IO_KMEM:
+ km_dp_init(dp, io_req->mem.ptr.addr);
+ break;
+
+ default:
+ return -EINVAL;
+ }
+
+ return 0;
+}
+
+/*
+ * New collapsed (a)synchronous interface.
+ *
+ * If the IO is asynchronous (i.e. it has notify.fn), you must either unplug
+ * the queue with blk_unplug() some time later or set REQ_SYNC in
+ * io_req->bi_opf. If you fail to do one of these, the IO will be submitted to
+ * the disk after q->unplug_delay, which defaults to 3ms in blk-settings.c.
+ */
+int dm_io(struct dm_io_request *io_req, unsigned num_regions,
+ struct dm_io_region *where, unsigned long *sync_error_bits)
+{
+ int r;
+ struct dpages dp;
+
+ r = dp_init(io_req, &dp, (unsigned long)where->count << SECTOR_SHIFT);
+ if (r)
+ return r;
+
+ if (!io_req->notify.fn)
+ return sync_io(io_req->client, num_regions, where,
+ io_req->bi_op, io_req->bi_op_flags, &dp,
+ sync_error_bits);
+
+ return async_io(io_req->client, num_regions, where, io_req->bi_op,
+ io_req->bi_op_flags, &dp, io_req->notify.fn,
+ io_req->notify.context);
+}
+EXPORT_SYMBOL(dm_io);
+
+int __init dm_io_init(void)
+{
+ _dm_io_cache = KMEM_CACHE(io, 0);
+ if (!_dm_io_cache)
+ return -ENOMEM;
+
+ return 0;
+}
+
+void dm_io_exit(void)
+{
+ kmem_cache_destroy(_dm_io_cache);
+ _dm_io_cache = NULL;
+}