[T106][ZXW-22]7520V3SCV2.01.01.02P42U09_VEC_V0.8_AP_VEC origin source commit
Change-Id: Ic6e05d89ecd62fc34f82b23dcf306c93764aec4b
diff --git a/ap/os/linux/linux-3.4.x/drivers/md/dm.c b/ap/os/linux/linux-3.4.x/drivers/md/dm.c
new file mode 100644
index 0000000..a335e68
--- /dev/null
+++ b/ap/os/linux/linux-3.4.x/drivers/md/dm.c
@@ -0,0 +1,2800 @@
+/*
+ * Copyright (C) 2001, 2002 Sistina Software (UK) Limited.
+ * Copyright (C) 2004-2008 Red Hat, Inc. All rights reserved.
+ *
+ * This file is released under the GPL.
+ */
+
+#include "dm.h"
+#include "dm-uevent.h"
+
+#include <linux/init.h>
+#include <linux/module.h>
+#include <linux/mutex.h>
+#include <linux/moduleparam.h>
+#include <linux/blkpg.h>
+#include <linux/bio.h>
+#include <linux/mempool.h>
+#include <linux/slab.h>
+#include <linux/idr.h>
+#include <linux/hdreg.h>
+#include <linux/delay.h>
+
+#include <trace/events/block.h>
+
+#define DM_MSG_PREFIX "core"
+
+#ifdef CONFIG_PRINTK
+/*
+ * ratelimit state to be used in DMXXX_LIMIT().
+ */
+DEFINE_RATELIMIT_STATE(dm_ratelimit_state,
+ DEFAULT_RATELIMIT_INTERVAL,
+ DEFAULT_RATELIMIT_BURST);
+EXPORT_SYMBOL(dm_ratelimit_state);
+#endif
+
+/*
+ * Cookies are numeric values sent with CHANGE and REMOVE
+ * uevents while resuming, removing or renaming the device.
+ */
+#define DM_COOKIE_ENV_VAR_NAME "DM_COOKIE"
+#define DM_COOKIE_LENGTH 24
+
+static const char *_name = DM_NAME;
+
+static unsigned int major = 0;
+static unsigned int _major = 0;
+
+static DEFINE_IDR(_minor_idr);
+
+static DEFINE_SPINLOCK(_minor_lock);
+/*
+ * For bio-based dm.
+ * One of these is allocated per bio.
+ */
+struct dm_io {
+ struct mapped_device *md;
+ int error;
+ atomic_t io_count;
+ struct bio *bio;
+ unsigned long start_time;
+ spinlock_t endio_lock;
+};
+
+/*
+ * For bio-based dm.
+ * One of these is allocated per target within a bio. Hopefully
+ * this will be simplified out one day.
+ */
+struct dm_target_io {
+ struct dm_io *io;
+ struct dm_target *ti;
+ union map_info info;
+};
+
+/*
+ * For request-based dm.
+ * One of these is allocated per request.
+ */
+struct dm_rq_target_io {
+ struct mapped_device *md;
+ struct dm_target *ti;
+ struct request *orig, clone;
+ int error;
+ union map_info info;
+};
+
+/*
+ * For request-based dm.
+ * One of these is allocated per bio.
+ */
+struct dm_rq_clone_bio_info {
+ struct bio *orig;
+ struct dm_rq_target_io *tio;
+};
+
+union map_info *dm_get_mapinfo(struct bio *bio)
+{
+ if (bio && bio->bi_private)
+ return &((struct dm_target_io *)bio->bi_private)->info;
+ return NULL;
+}
+
+union map_info *dm_get_rq_mapinfo(struct request *rq)
+{
+ if (rq && rq->end_io_data)
+ return &((struct dm_rq_target_io *)rq->end_io_data)->info;
+ return NULL;
+}
+EXPORT_SYMBOL_GPL(dm_get_rq_mapinfo);
+
+#define MINOR_ALLOCED ((void *)-1)
+
+/*
+ * Bits for the md->flags field.
+ */
+#define DMF_BLOCK_IO_FOR_SUSPEND 0
+#define DMF_SUSPENDED 1
+#define DMF_FROZEN 2
+#define DMF_FREEING 3
+#define DMF_DELETING 4
+#define DMF_NOFLUSH_SUSPENDING 5
+#define DMF_MERGE_IS_OPTIONAL 6
+
+/*
+ * Work processed by per-device workqueue.
+ */
+struct mapped_device {
+ struct rw_semaphore io_lock;
+ struct mutex suspend_lock;
+ rwlock_t map_lock;
+ atomic_t holders;
+ atomic_t open_count;
+
+ unsigned long flags;
+
+ struct request_queue *queue;
+ unsigned type;
+ /* Protect queue and type against concurrent access. */
+ struct mutex type_lock;
+
+ struct target_type *immutable_target_type;
+
+ struct gendisk *disk;
+ char name[16];
+
+ void *interface_ptr;
+
+ /*
+ * A list of ios that arrived while we were suspended.
+ */
+ atomic_t pending[2];
+ wait_queue_head_t wait;
+ struct work_struct work;
+ struct bio_list deferred;
+ spinlock_t deferred_lock;
+
+ /*
+ * Processing queue (flush)
+ */
+ struct workqueue_struct *wq;
+
+ /*
+ * The current mapping.
+ */
+ struct dm_table *map;
+
+ /*
+ * io objects are allocated from here.
+ */
+ mempool_t *io_pool;
+ mempool_t *tio_pool;
+
+ struct bio_set *bs;
+
+ /*
+ * Event handling.
+ */
+ atomic_t event_nr;
+ wait_queue_head_t eventq;
+ atomic_t uevent_seq;
+ struct list_head uevent_list;
+ spinlock_t uevent_lock; /* Protect access to uevent_list */
+
+ /*
+ * freeze/thaw support require holding onto a super block
+ */
+ struct super_block *frozen_sb;
+ struct block_device *bdev;
+
+ /* forced geometry settings */
+ struct hd_geometry geometry;
+
+ /* kobject and completion */
+ struct dm_kobject_holder kobj_holder;
+
+ /* zero-length flush that will be cloned and submitted to targets */
+ struct bio flush_bio;
+};
+
+/*
+ * For mempools pre-allocation at the table loading time.
+ */
+struct dm_md_mempools {
+ mempool_t *io_pool;
+ mempool_t *tio_pool;
+ struct bio_set *bs;
+};
+
+#define MIN_IOS 256
+static struct kmem_cache *_io_cache;
+static struct kmem_cache *_tio_cache;
+static struct kmem_cache *_rq_tio_cache;
+static struct kmem_cache *_rq_bio_info_cache;
+
+static int __init local_init(void)
+{
+ int r = -ENOMEM;
+
+ /* allocate a slab for the dm_ios */
+ _io_cache = KMEM_CACHE(dm_io, 0);
+ if (!_io_cache)
+ return r;
+
+ /* allocate a slab for the target ios */
+ _tio_cache = KMEM_CACHE(dm_target_io, 0);
+ if (!_tio_cache)
+ goto out_free_io_cache;
+
+ _rq_tio_cache = KMEM_CACHE(dm_rq_target_io, 0);
+ if (!_rq_tio_cache)
+ goto out_free_tio_cache;
+
+ _rq_bio_info_cache = KMEM_CACHE(dm_rq_clone_bio_info, 0);
+ if (!_rq_bio_info_cache)
+ goto out_free_rq_tio_cache;
+
+ r = dm_uevent_init();
+ if (r)
+ goto out_free_rq_bio_info_cache;
+
+ _major = major;
+ r = register_blkdev(_major, _name);
+ if (r < 0)
+ goto out_uevent_exit;
+
+ if (!_major)
+ _major = r;
+
+ return 0;
+
+out_uevent_exit:
+ dm_uevent_exit();
+out_free_rq_bio_info_cache:
+ kmem_cache_destroy(_rq_bio_info_cache);
+out_free_rq_tio_cache:
+ kmem_cache_destroy(_rq_tio_cache);
+out_free_tio_cache:
+ kmem_cache_destroy(_tio_cache);
+out_free_io_cache:
+ kmem_cache_destroy(_io_cache);
+
+ return r;
+}
+
+static void local_exit(void)
+{
+ kmem_cache_destroy(_rq_bio_info_cache);
+ kmem_cache_destroy(_rq_tio_cache);
+ kmem_cache_destroy(_tio_cache);
+ kmem_cache_destroy(_io_cache);
+ unregister_blkdev(_major, _name);
+ dm_uevent_exit();
+
+ _major = 0;
+
+ DMINFO("cleaned up");
+}
+
+static int (*_inits[])(void) __initdata = {
+ local_init,
+ dm_target_init,
+ dm_linear_init,
+ dm_stripe_init,
+ dm_io_init,
+ dm_kcopyd_init,
+ dm_interface_init,
+};
+
+static void (*_exits[])(void) = {
+ local_exit,
+ dm_target_exit,
+ dm_linear_exit,
+ dm_stripe_exit,
+ dm_io_exit,
+ dm_kcopyd_exit,
+ dm_interface_exit,
+};
+
+static int __init dm_init(void)
+{
+ const int count = ARRAY_SIZE(_inits);
+
+ int r, i;
+
+ for (i = 0; i < count; i++) {
+ r = _inits[i]();
+ if (r)
+ goto bad;
+ }
+
+ return 0;
+
+ bad:
+ while (i--)
+ _exits[i]();
+
+ return r;
+}
+
+static void __exit dm_exit(void)
+{
+ int i = ARRAY_SIZE(_exits);
+
+ while (i--)
+ _exits[i]();
+
+ /*
+ * Should be empty by this point.
+ */
+ idr_remove_all(&_minor_idr);
+ idr_destroy(&_minor_idr);
+}
+
+/*
+ * Block device functions
+ */
+int dm_deleting_md(struct mapped_device *md)
+{
+ return test_bit(DMF_DELETING, &md->flags);
+}
+
+static int dm_blk_open(struct block_device *bdev, fmode_t mode)
+{
+ struct mapped_device *md;
+
+ spin_lock(&_minor_lock);
+
+ md = bdev->bd_disk->private_data;
+ if (!md)
+ goto out;
+
+ if (test_bit(DMF_FREEING, &md->flags) ||
+ dm_deleting_md(md)) {
+ md = NULL;
+ goto out;
+ }
+
+ dm_get(md);
+ atomic_inc(&md->open_count);
+
+out:
+ spin_unlock(&_minor_lock);
+
+ return md ? 0 : -ENXIO;
+}
+
+static int dm_blk_close(struct gendisk *disk, fmode_t mode)
+{
+ struct mapped_device *md = disk->private_data;
+
+ spin_lock(&_minor_lock);
+
+ atomic_dec(&md->open_count);
+ dm_put(md);
+
+ spin_unlock(&_minor_lock);
+
+ return 0;
+}
+
+int dm_open_count(struct mapped_device *md)
+{
+ return atomic_read(&md->open_count);
+}
+
+/*
+ * Guarantees nothing is using the device before it's deleted.
+ */
+int dm_lock_for_deletion(struct mapped_device *md)
+{
+ int r = 0;
+
+ spin_lock(&_minor_lock);
+
+ if (dm_open_count(md))
+ r = -EBUSY;
+ else
+ set_bit(DMF_DELETING, &md->flags);
+
+ spin_unlock(&_minor_lock);
+
+ return r;
+}
+
+static int dm_blk_getgeo(struct block_device *bdev, struct hd_geometry *geo)
+{
+ struct mapped_device *md = bdev->bd_disk->private_data;
+
+ return dm_get_geometry(md, geo);
+}
+
+static int dm_blk_ioctl(struct block_device *bdev, fmode_t mode,
+ unsigned int cmd, unsigned long arg)
+{
+ struct mapped_device *md = bdev->bd_disk->private_data;
+ struct dm_table *map = dm_get_live_table(md);
+ struct dm_target *tgt;
+ int r = -ENOTTY;
+
+ if (!map || !dm_table_get_size(map))
+ goto out;
+
+ /* We only support devices that have a single target */
+ if (dm_table_get_num_targets(map) != 1)
+ goto out;
+
+ tgt = dm_table_get_target(map, 0);
+
+ if (dm_suspended_md(md)) {
+ r = -EAGAIN;
+ goto out;
+ }
+
+ if (tgt->type->ioctl)
+ r = tgt->type->ioctl(tgt, cmd, arg);
+
+out:
+ dm_table_put(map);
+
+ return r;
+}
+
+static struct dm_io *alloc_io(struct mapped_device *md)
+{
+ return mempool_alloc(md->io_pool, GFP_NOIO);
+}
+
+static void free_io(struct mapped_device *md, struct dm_io *io)
+{
+ mempool_free(io, md->io_pool);
+}
+
+static void free_tio(struct mapped_device *md, struct dm_target_io *tio)
+{
+ mempool_free(tio, md->tio_pool);
+}
+
+static struct dm_rq_target_io *alloc_rq_tio(struct mapped_device *md,
+ gfp_t gfp_mask)
+{
+ return mempool_alloc(md->tio_pool, gfp_mask);
+}
+
+static void free_rq_tio(struct dm_rq_target_io *tio)
+{
+ mempool_free(tio, tio->md->tio_pool);
+}
+
+static struct dm_rq_clone_bio_info *alloc_bio_info(struct mapped_device *md)
+{
+ return mempool_alloc(md->io_pool, GFP_ATOMIC);
+}
+
+static void free_bio_info(struct dm_rq_clone_bio_info *info)
+{
+ mempool_free(info, info->tio->md->io_pool);
+}
+
+static int md_in_flight(struct mapped_device *md)
+{
+ return atomic_read(&md->pending[READ]) +
+ atomic_read(&md->pending[WRITE]);
+}
+
+static void start_io_acct(struct dm_io *io)
+{
+ struct mapped_device *md = io->md;
+ int cpu;
+ int rw = bio_data_dir(io->bio);
+
+ io->start_time = jiffies;
+
+ cpu = part_stat_lock();
+ part_round_stats(cpu, &dm_disk(md)->part0);
+ part_stat_unlock();
+ atomic_set(&dm_disk(md)->part0.in_flight[rw],
+ atomic_inc_return(&md->pending[rw]));
+}
+
+static void end_io_acct(struct dm_io *io)
+{
+ struct mapped_device *md = io->md;
+ struct bio *bio = io->bio;
+ unsigned long duration = jiffies - io->start_time;
+ int pending, cpu;
+ int rw = bio_data_dir(bio);
+
+ cpu = part_stat_lock();
+ part_round_stats(cpu, &dm_disk(md)->part0);
+ part_stat_add(cpu, &dm_disk(md)->part0, ticks[rw], duration);
+ part_stat_unlock();
+
+ /*
+ * After this is decremented the bio must not be touched if it is
+ * a flush.
+ */
+ pending = atomic_dec_return(&md->pending[rw]);
+ atomic_set(&dm_disk(md)->part0.in_flight[rw], pending);
+ pending += atomic_read(&md->pending[rw^0x1]);
+
+ /* nudge anyone waiting on suspend queue */
+ if (!pending)
+ wake_up(&md->wait);
+}
+
+/*
+ * Add the bio to the list of deferred io.
+ */
+static void queue_io(struct mapped_device *md, struct bio *bio)
+{
+ unsigned long flags;
+
+ spin_lock_irqsave(&md->deferred_lock, flags);
+ bio_list_add(&md->deferred, bio);
+ spin_unlock_irqrestore(&md->deferred_lock, flags);
+ queue_work(md->wq, &md->work);
+}
+
+/*
+ * Everyone (including functions in this file), should use this
+ * function to access the md->map field, and make sure they call
+ * dm_table_put() when finished.
+ */
+struct dm_table *dm_get_live_table(struct mapped_device *md)
+{
+ struct dm_table *t;
+ unsigned long flags;
+
+ read_lock_irqsave(&md->map_lock, flags);
+ t = md->map;
+ if (t)
+ dm_table_get(t);
+ read_unlock_irqrestore(&md->map_lock, flags);
+
+ return t;
+}
+
+/*
+ * Get the geometry associated with a dm device
+ */
+int dm_get_geometry(struct mapped_device *md, struct hd_geometry *geo)
+{
+ *geo = md->geometry;
+
+ return 0;
+}
+
+/*
+ * Set the geometry of a device.
+ */
+int dm_set_geometry(struct mapped_device *md, struct hd_geometry *geo)
+{
+ sector_t sz = (sector_t)geo->cylinders * geo->heads * geo->sectors;
+
+ if (geo->start > sz) {
+ DMWARN("Start sector is beyond the geometry limits.");
+ return -EINVAL;
+ }
+
+ md->geometry = *geo;
+
+ return 0;
+}
+
+/*-----------------------------------------------------------------
+ * CRUD START:
+ * A more elegant soln is in the works that uses the queue
+ * merge fn, unfortunately there are a couple of changes to
+ * the block layer that I want to make for this. So in the
+ * interests of getting something for people to use I give
+ * you this clearly demarcated crap.
+ *---------------------------------------------------------------*/
+
+static int __noflush_suspending(struct mapped_device *md)
+{
+ return test_bit(DMF_NOFLUSH_SUSPENDING, &md->flags);
+}
+
+/*
+ * Decrements the number of outstanding ios that a bio has been
+ * cloned into, completing the original io if necc.
+ */
+static void dec_pending(struct dm_io *io, int error)
+{
+ unsigned long flags;
+ int io_error;
+ struct bio *bio;
+ struct mapped_device *md = io->md;
+
+ /* Push-back supersedes any I/O errors */
+ if (unlikely(error)) {
+ spin_lock_irqsave(&io->endio_lock, flags);
+ if (!(io->error > 0 && __noflush_suspending(md)))
+ io->error = error;
+ spin_unlock_irqrestore(&io->endio_lock, flags);
+ }
+
+ if (atomic_dec_and_test(&io->io_count)) {
+ if (io->error == DM_ENDIO_REQUEUE) {
+ /*
+ * Target requested pushing back the I/O.
+ */
+ spin_lock_irqsave(&md->deferred_lock, flags);
+ if (__noflush_suspending(md))
+ bio_list_add_head(&md->deferred, io->bio);
+ else
+ /* noflush suspend was interrupted. */
+ io->error = -EIO;
+ spin_unlock_irqrestore(&md->deferred_lock, flags);
+ }
+
+ io_error = io->error;
+ bio = io->bio;
+ end_io_acct(io);
+ free_io(md, io);
+
+ if (io_error == DM_ENDIO_REQUEUE)
+ return;
+
+ if ((bio->bi_rw & REQ_FLUSH) && bio->bi_size) {
+ /*
+ * Preflush done for flush with data, reissue
+ * without REQ_FLUSH.
+ */
+ bio->bi_rw &= ~REQ_FLUSH;
+ queue_io(md, bio);
+ } else {
+ /* done with normal IO or empty flush */
+ trace_block_bio_complete(md->queue, bio, io_error);
+ bio_endio(bio, io_error);
+ }
+ }
+}
+
+static void clone_endio(struct bio *bio, int error)
+{
+ int r = 0;
+ struct dm_target_io *tio = bio->bi_private;
+ struct dm_io *io = tio->io;
+ struct mapped_device *md = tio->io->md;
+ dm_endio_fn endio = tio->ti->type->end_io;
+
+ if (!bio_flagged(bio, BIO_UPTODATE) && !error)
+ error = -EIO;
+
+ if (endio) {
+ r = endio(tio->ti, bio, error, &tio->info);
+ if (r < 0 || r == DM_ENDIO_REQUEUE)
+ /*
+ * error and requeue request are handled
+ * in dec_pending().
+ */
+ error = r;
+ else if (r == DM_ENDIO_INCOMPLETE)
+ /* The target will handle the io */
+ return;
+ else if (r) {
+ DMWARN("unimplemented target endio return value: %d", r);
+ BUG();
+ }
+ }
+
+ /*
+ * Store md for cleanup instead of tio which is about to get freed.
+ */
+ bio->bi_private = md->bs;
+
+ free_tio(md, tio);
+ bio_put(bio);
+ dec_pending(io, error);
+}
+
+/*
+ * Partial completion handling for request-based dm
+ */
+static void end_clone_bio(struct bio *clone, int error)
+{
+ struct dm_rq_clone_bio_info *info = clone->bi_private;
+ struct dm_rq_target_io *tio = info->tio;
+ struct bio *bio = info->orig;
+ unsigned int nr_bytes = info->orig->bi_size;
+
+ bio_put(clone);
+
+ if (tio->error)
+ /*
+ * An error has already been detected on the request.
+ * Once error occurred, just let clone->end_io() handle
+ * the remainder.
+ */
+ return;
+ else if (error) {
+ /*
+ * Don't notice the error to the upper layer yet.
+ * The error handling decision is made by the target driver,
+ * when the request is completed.
+ */
+ tio->error = error;
+ return;
+ }
+
+ /*
+ * I/O for the bio successfully completed.
+ * Notice the data completion to the upper layer.
+ */
+
+ /*
+ * bios are processed from the head of the list.
+ * So the completing bio should always be rq->bio.
+ * If it's not, something wrong is happening.
+ */
+ if (tio->orig->bio != bio)
+ DMERR("bio completion is going in the middle of the request");
+
+ /*
+ * Update the original request.
+ * Do not use blk_end_request() here, because it may complete
+ * the original request before the clone, and break the ordering.
+ */
+ blk_update_request(tio->orig, 0, nr_bytes);
+}
+
+/*
+ * Don't touch any member of the md after calling this function because
+ * the md may be freed in dm_put() at the end of this function.
+ * Or do dm_get() before calling this function and dm_put() later.
+ */
+static void rq_completed(struct mapped_device *md, int rw, int run_queue)
+{
+ atomic_dec(&md->pending[rw]);
+
+ /* nudge anyone waiting on suspend queue */
+ if (!md_in_flight(md))
+ wake_up(&md->wait);
+
+ /*
+ * Run this off this callpath, as drivers could invoke end_io while
+ * inside their request_fn (and holding the queue lock). Calling
+ * back into ->request_fn() could deadlock attempting to grab the
+ * queue lock again.
+ */
+ if (run_queue)
+ blk_run_queue_async(md->queue);
+
+ /*
+ * dm_put() must be at the end of this function. See the comment above
+ */
+ dm_put(md);
+}
+
+static void free_rq_clone(struct request *clone)
+{
+ struct dm_rq_target_io *tio = clone->end_io_data;
+
+ blk_rq_unprep_clone(clone);
+ free_rq_tio(tio);
+}
+
+/*
+ * Complete the clone and the original request.
+ * Must be called without queue lock.
+ */
+static void dm_end_request(struct request *clone, int error)
+{
+ int rw = rq_data_dir(clone);
+ struct dm_rq_target_io *tio = clone->end_io_data;
+ struct mapped_device *md = tio->md;
+ struct request *rq = tio->orig;
+
+ if (rq->cmd_type == REQ_TYPE_BLOCK_PC) {
+ rq->errors = clone->errors;
+ rq->resid_len = clone->resid_len;
+
+ if (rq->sense)
+ /*
+ * We are using the sense buffer of the original
+ * request.
+ * So setting the length of the sense data is enough.
+ */
+ rq->sense_len = clone->sense_len;
+ }
+
+ free_rq_clone(clone);
+ blk_end_request_all(rq, error);
+ rq_completed(md, rw, true);
+}
+
+static void dm_unprep_request(struct request *rq)
+{
+ struct request *clone = rq->special;
+
+ rq->special = NULL;
+ rq->cmd_flags &= ~REQ_DONTPREP;
+
+ free_rq_clone(clone);
+}
+
+/*
+ * Requeue the original request of a clone.
+ */
+void dm_requeue_unmapped_request(struct request *clone)
+{
+ int rw = rq_data_dir(clone);
+ struct dm_rq_target_io *tio = clone->end_io_data;
+ struct mapped_device *md = tio->md;
+ struct request *rq = tio->orig;
+ struct request_queue *q = rq->q;
+ unsigned long flags;
+
+ dm_unprep_request(rq);
+
+ spin_lock_irqsave(q->queue_lock, flags);
+ blk_requeue_request(q, rq);
+ spin_unlock_irqrestore(q->queue_lock, flags);
+
+ rq_completed(md, rw, 0);
+}
+EXPORT_SYMBOL_GPL(dm_requeue_unmapped_request);
+
+static void __stop_queue(struct request_queue *q)
+{
+ blk_stop_queue(q);
+}
+
+static void stop_queue(struct request_queue *q)
+{
+ unsigned long flags;
+
+ spin_lock_irqsave(q->queue_lock, flags);
+ __stop_queue(q);
+ spin_unlock_irqrestore(q->queue_lock, flags);
+}
+
+static void __start_queue(struct request_queue *q)
+{
+ if (blk_queue_stopped(q))
+ blk_start_queue(q);
+}
+
+static void start_queue(struct request_queue *q)
+{
+ unsigned long flags;
+
+ spin_lock_irqsave(q->queue_lock, flags);
+ __start_queue(q);
+ spin_unlock_irqrestore(q->queue_lock, flags);
+}
+
+static void dm_done(struct request *clone, int error, bool mapped)
+{
+ int r = error;
+ struct dm_rq_target_io *tio = clone->end_io_data;
+ dm_request_endio_fn rq_end_io = NULL;
+
+ if (tio->ti) {
+ rq_end_io = tio->ti->type->rq_end_io;
+
+ if (mapped && rq_end_io)
+ r = rq_end_io(tio->ti, clone, error, &tio->info);
+ }
+
+ if (r <= 0)
+ /* The target wants to complete the I/O */
+ dm_end_request(clone, r);
+ else if (r == DM_ENDIO_INCOMPLETE)
+ /* The target will handle the I/O */
+ return;
+ else if (r == DM_ENDIO_REQUEUE)
+ /* The target wants to requeue the I/O */
+ dm_requeue_unmapped_request(clone);
+ else {
+ DMWARN("unimplemented target endio return value: %d", r);
+ BUG();
+ }
+}
+
+/*
+ * Request completion handler for request-based dm
+ */
+static void dm_softirq_done(struct request *rq)
+{
+ bool mapped = true;
+ struct request *clone = rq->completion_data;
+ struct dm_rq_target_io *tio = clone->end_io_data;
+
+ if (rq->cmd_flags & REQ_FAILED)
+ mapped = false;
+
+ dm_done(clone, tio->error, mapped);
+}
+
+/*
+ * Complete the clone and the original request with the error status
+ * through softirq context.
+ */
+static void dm_complete_request(struct request *clone, int error)
+{
+ struct dm_rq_target_io *tio = clone->end_io_data;
+ struct request *rq = tio->orig;
+
+ tio->error = error;
+ rq->completion_data = clone;
+ blk_complete_request(rq);
+}
+
+/*
+ * Complete the not-mapped clone and the original request with the error status
+ * through softirq context.
+ * Target's rq_end_io() function isn't called.
+ * This may be used when the target's map_rq() function fails.
+ */
+void dm_kill_unmapped_request(struct request *clone, int error)
+{
+ struct dm_rq_target_io *tio = clone->end_io_data;
+ struct request *rq = tio->orig;
+
+ rq->cmd_flags |= REQ_FAILED;
+ dm_complete_request(clone, error);
+}
+EXPORT_SYMBOL_GPL(dm_kill_unmapped_request);
+
+/*
+ * Called with the queue lock held
+ */
+static void end_clone_request(struct request *clone, int error)
+{
+ /*
+ * For just cleaning up the information of the queue in which
+ * the clone was dispatched.
+ * The clone is *NOT* freed actually here because it is alloced from
+ * dm own mempool and REQ_ALLOCED isn't set in clone->cmd_flags.
+ */
+ __blk_put_request(clone->q, clone);
+
+ /*
+ * Actual request completion is done in a softirq context which doesn't
+ * hold the queue lock. Otherwise, deadlock could occur because:
+ * - another request may be submitted by the upper level driver
+ * of the stacking during the completion
+ * - the submission which requires queue lock may be done
+ * against this queue
+ */
+ dm_complete_request(clone, error);
+}
+
+/*
+ * Return maximum size of I/O possible at the supplied sector up to the current
+ * target boundary.
+ */
+static sector_t max_io_len_target_boundary(sector_t sector, struct dm_target *ti)
+{
+ sector_t target_offset = dm_target_offset(ti, sector);
+
+ return ti->len - target_offset;
+}
+
+static sector_t max_io_len(sector_t sector, struct dm_target *ti)
+{
+ sector_t len = max_io_len_target_boundary(sector, ti);
+
+ /*
+ * Does the target need to split even further ?
+ */
+ if (ti->split_io) {
+ sector_t boundary;
+ sector_t offset = dm_target_offset(ti, sector);
+ boundary = ((offset + ti->split_io) & ~(ti->split_io - 1))
+ - offset;
+ if (len > boundary)
+ len = boundary;
+ }
+
+ return len;
+}
+
+static void __map_bio(struct dm_target *ti, struct bio *clone,
+ struct dm_target_io *tio)
+{
+ int r;
+ sector_t sector;
+ struct mapped_device *md;
+
+ clone->bi_end_io = clone_endio;
+ clone->bi_private = tio;
+
+ /*
+ * Map the clone. If r == 0 we don't need to do
+ * anything, the target has assumed ownership of
+ * this io.
+ */
+ atomic_inc(&tio->io->io_count);
+ sector = clone->bi_sector;
+ r = ti->type->map(ti, clone, &tio->info);
+ if (r == DM_MAPIO_REMAPPED) {
+ /* the bio has been remapped so dispatch it */
+
+ trace_block_bio_remap(bdev_get_queue(clone->bi_bdev), clone,
+ tio->io->bio->bi_bdev->bd_dev, sector);
+
+ generic_make_request(clone);
+ } else if (r < 0 || r == DM_MAPIO_REQUEUE) {
+ /* error the io and bail out, or requeue it if needed */
+ md = tio->io->md;
+ dec_pending(tio->io, r);
+ /*
+ * Store bio_set for cleanup.
+ */
+ clone->bi_end_io = NULL;
+ clone->bi_private = md->bs;
+ bio_put(clone);
+ free_tio(md, tio);
+ } else if (r) {
+ DMWARN("unimplemented target map return value: %d", r);
+ BUG();
+ }
+}
+
+struct clone_info {
+ struct mapped_device *md;
+ struct dm_table *map;
+ struct bio *bio;
+ struct dm_io *io;
+ sector_t sector;
+ sector_t sector_count;
+ unsigned short idx;
+};
+
+static void dm_bio_destructor(struct bio *bio)
+{
+ struct bio_set *bs = bio->bi_private;
+
+ bio_free(bio, bs);
+}
+
+/*
+ * Creates a little bio that just does part of a bvec.
+ */
+static struct bio *split_bvec(struct bio *bio, sector_t sector,
+ unsigned short idx, unsigned int offset,
+ unsigned int len, struct bio_set *bs)
+{
+ struct bio *clone;
+ struct bio_vec *bv = bio->bi_io_vec + idx;
+
+ clone = bio_alloc_bioset(GFP_NOIO, 1, bs);
+ clone->bi_destructor = dm_bio_destructor;
+ *clone->bi_io_vec = *bv;
+
+ clone->bi_sector = sector;
+ clone->bi_bdev = bio->bi_bdev;
+ clone->bi_rw = bio->bi_rw;
+ clone->bi_vcnt = 1;
+ clone->bi_size = to_bytes(len);
+ clone->bi_io_vec->bv_offset = offset;
+ clone->bi_io_vec->bv_len = clone->bi_size;
+ clone->bi_flags |= 1 << BIO_CLONED;
+
+ if (bio_integrity(bio)) {
+ bio_integrity_clone(clone, bio, GFP_NOIO, bs);
+ bio_integrity_trim(clone,
+ bio_sector_offset(bio, idx, offset), len);
+ }
+
+ return clone;
+}
+
+/*
+ * Creates a bio that consists of range of complete bvecs.
+ */
+static struct bio *clone_bio(struct bio *bio, sector_t sector,
+ unsigned short idx, unsigned short bv_count,
+ unsigned int len, struct bio_set *bs)
+{
+ struct bio *clone;
+
+ clone = bio_alloc_bioset(GFP_NOIO, bio->bi_max_vecs, bs);
+ __bio_clone(clone, bio);
+ clone->bi_destructor = dm_bio_destructor;
+ clone->bi_sector = sector;
+ clone->bi_idx = idx;
+ clone->bi_vcnt = idx + bv_count;
+ clone->bi_size = to_bytes(len);
+ clone->bi_flags &= ~(1 << BIO_SEG_VALID);
+
+ if (bio_integrity(bio)) {
+ bio_integrity_clone(clone, bio, GFP_NOIO, bs);
+
+ if (idx != bio->bi_idx || clone->bi_size < bio->bi_size)
+ bio_integrity_trim(clone,
+ bio_sector_offset(bio, idx, 0), len);
+ }
+
+ return clone;
+}
+
+static struct dm_target_io *alloc_tio(struct clone_info *ci,
+ struct dm_target *ti)
+{
+ struct dm_target_io *tio = mempool_alloc(ci->md->tio_pool, GFP_NOIO);
+
+ tio->io = ci->io;
+ tio->ti = ti;
+ memset(&tio->info, 0, sizeof(tio->info));
+
+ return tio;
+}
+
+static void __issue_target_request(struct clone_info *ci, struct dm_target *ti,
+ unsigned request_nr, sector_t len)
+{
+ struct dm_target_io *tio = alloc_tio(ci, ti);
+ struct bio *clone;
+
+ tio->info.target_request_nr = request_nr;
+
+ /*
+ * Discard requests require the bio's inline iovecs be initialized.
+ * ci->bio->bi_max_vecs is BIO_INLINE_VECS anyway, for both flush
+ * and discard, so no need for concern about wasted bvec allocations.
+ */
+ clone = bio_alloc_bioset(GFP_NOIO, ci->bio->bi_max_vecs, ci->md->bs);
+ __bio_clone(clone, ci->bio);
+ clone->bi_destructor = dm_bio_destructor;
+ if (len) {
+ clone->bi_sector = ci->sector;
+ clone->bi_size = to_bytes(len);
+ }
+
+ __map_bio(ti, clone, tio);
+}
+
+static void __issue_target_requests(struct clone_info *ci, struct dm_target *ti,
+ unsigned num_requests, sector_t len)
+{
+ unsigned request_nr;
+
+ for (request_nr = 0; request_nr < num_requests; request_nr++)
+ __issue_target_request(ci, ti, request_nr, len);
+}
+
+static int __clone_and_map_empty_flush(struct clone_info *ci)
+{
+ unsigned target_nr = 0;
+ struct dm_target *ti;
+
+ BUG_ON(bio_has_data(ci->bio));
+ while ((ti = dm_table_get_target(ci->map, target_nr++)))
+ __issue_target_requests(ci, ti, ti->num_flush_requests, 0);
+
+ return 0;
+}
+
+/*
+ * Perform all io with a single clone.
+ */
+static void __clone_and_map_simple(struct clone_info *ci, struct dm_target *ti)
+{
+ struct bio *clone, *bio = ci->bio;
+ struct dm_target_io *tio;
+
+ tio = alloc_tio(ci, ti);
+ clone = clone_bio(bio, ci->sector, ci->idx,
+ bio->bi_vcnt - ci->idx, ci->sector_count,
+ ci->md->bs);
+ __map_bio(ti, clone, tio);
+ ci->sector_count = 0;
+}
+
+static int __clone_and_map_discard(struct clone_info *ci)
+{
+ struct dm_target *ti;
+ sector_t len;
+
+ do {
+ ti = dm_table_find_target(ci->map, ci->sector);
+ if (!dm_target_is_valid(ti))
+ return -EIO;
+
+ /*
+ * Even though the device advertised discard support,
+ * that does not mean every target supports it, and
+ * reconfiguration might also have changed that since the
+ * check was performed.
+ */
+ if (!ti->num_discard_requests)
+ return -EOPNOTSUPP;
+
+ len = min(ci->sector_count, max_io_len_target_boundary(ci->sector, ti));
+
+ __issue_target_requests(ci, ti, ti->num_discard_requests, len);
+
+ ci->sector += len;
+ } while (ci->sector_count -= len);
+
+ return 0;
+}
+
+static int __clone_and_map(struct clone_info *ci)
+{
+ struct bio *clone, *bio = ci->bio;
+ struct dm_target *ti;
+ sector_t len = 0, max;
+ struct dm_target_io *tio;
+
+ if (unlikely(bio->bi_rw & REQ_DISCARD))
+ return __clone_and_map_discard(ci);
+
+ ti = dm_table_find_target(ci->map, ci->sector);
+ if (!dm_target_is_valid(ti))
+ return -EIO;
+
+ max = max_io_len(ci->sector, ti);
+
+ if (ci->sector_count <= max) {
+ /*
+ * Optimise for the simple case where we can do all of
+ * the remaining io with a single clone.
+ */
+ __clone_and_map_simple(ci, ti);
+
+ } else if (to_sector(bio->bi_io_vec[ci->idx].bv_len) <= max) {
+ /*
+ * There are some bvecs that don't span targets.
+ * Do as many of these as possible.
+ */
+ int i;
+ sector_t remaining = max;
+ sector_t bv_len;
+
+ for (i = ci->idx; remaining && (i < bio->bi_vcnt); i++) {
+ bv_len = to_sector(bio->bi_io_vec[i].bv_len);
+
+ if (bv_len > remaining)
+ break;
+
+ remaining -= bv_len;
+ len += bv_len;
+ }
+
+ tio = alloc_tio(ci, ti);
+ clone = clone_bio(bio, ci->sector, ci->idx, i - ci->idx, len,
+ ci->md->bs);
+ __map_bio(ti, clone, tio);
+
+ ci->sector += len;
+ ci->sector_count -= len;
+ ci->idx = i;
+
+ } else {
+ /*
+ * Handle a bvec that must be split between two or more targets.
+ */
+ struct bio_vec *bv = bio->bi_io_vec + ci->idx;
+ sector_t remaining = to_sector(bv->bv_len);
+ unsigned int offset = 0;
+
+ do {
+ if (offset) {
+ ti = dm_table_find_target(ci->map, ci->sector);
+ if (!dm_target_is_valid(ti))
+ return -EIO;
+
+ max = max_io_len(ci->sector, ti);
+ }
+
+ len = min(remaining, max);
+
+ tio = alloc_tio(ci, ti);
+ clone = split_bvec(bio, ci->sector, ci->idx,
+ bv->bv_offset + offset, len,
+ ci->md->bs);
+
+ __map_bio(ti, clone, tio);
+
+ ci->sector += len;
+ ci->sector_count -= len;
+ offset += to_bytes(len);
+ } while (remaining -= len);
+
+ ci->idx++;
+ }
+
+ return 0;
+}
+
+/*
+ * Split the bio into several clones and submit it to targets.
+ */
+static void __split_and_process_bio(struct mapped_device *md, struct bio *bio)
+{
+ struct clone_info ci;
+ int error = 0;
+
+ ci.map = dm_get_live_table(md);
+ if (unlikely(!ci.map)) {
+ bio_io_error(bio);
+ return;
+ }
+
+ ci.md = md;
+ ci.io = alloc_io(md);
+ ci.io->error = 0;
+ atomic_set(&ci.io->io_count, 1);
+ ci.io->bio = bio;
+ ci.io->md = md;
+ spin_lock_init(&ci.io->endio_lock);
+ ci.sector = bio->bi_sector;
+ ci.idx = bio->bi_idx;
+
+ start_io_acct(ci.io);
+ if (bio->bi_rw & REQ_FLUSH) {
+ ci.bio = &ci.md->flush_bio;
+ ci.sector_count = 0;
+ error = __clone_and_map_empty_flush(&ci);
+ /* dec_pending submits any data associated with flush */
+ } else {
+ ci.bio = bio;
+ ci.sector_count = bio_sectors(bio);
+ while (ci.sector_count && !error)
+ error = __clone_and_map(&ci);
+ }
+
+ /* drop the extra reference count */
+ dec_pending(ci.io, error);
+ dm_table_put(ci.map);
+}
+/*-----------------------------------------------------------------
+ * CRUD END
+ *---------------------------------------------------------------*/
+
+static int dm_merge_bvec(struct request_queue *q,
+ struct bvec_merge_data *bvm,
+ struct bio_vec *biovec)
+{
+ struct mapped_device *md = q->queuedata;
+ struct dm_table *map = dm_get_live_table(md);
+ struct dm_target *ti;
+ sector_t max_sectors;
+ int max_size = 0;
+
+ if (unlikely(!map))
+ goto out;
+
+ ti = dm_table_find_target(map, bvm->bi_sector);
+ if (!dm_target_is_valid(ti))
+ goto out_table;
+
+ /*
+ * Find maximum amount of I/O that won't need splitting
+ */
+ max_sectors = min(max_io_len(bvm->bi_sector, ti),
+ (sector_t) BIO_MAX_SECTORS);
+ max_size = (max_sectors << SECTOR_SHIFT) - bvm->bi_size;
+ if (max_size < 0)
+ max_size = 0;
+
+ /*
+ * merge_bvec_fn() returns number of bytes
+ * it can accept at this offset
+ * max is precomputed maximal io size
+ */
+ if (max_size && ti->type->merge)
+ max_size = ti->type->merge(ti, bvm, biovec, max_size);
+ /*
+ * If the target doesn't support merge method and some of the devices
+ * provided their merge_bvec method (we know this by looking at
+ * queue_max_hw_sectors), then we can't allow bios with multiple vector
+ * entries. So always set max_size to 0, and the code below allows
+ * just one page.
+ */
+ else if (queue_max_hw_sectors(q) <= PAGE_SIZE >> 9)
+
+ max_size = 0;
+
+out_table:
+ dm_table_put(map);
+
+out:
+ /*
+ * Always allow an entire first page
+ */
+ if (max_size <= biovec->bv_len && !(bvm->bi_size >> SECTOR_SHIFT))
+ max_size = biovec->bv_len;
+
+ return max_size;
+}
+
+/*
+ * The request function that just remaps the bio built up by
+ * dm_merge_bvec.
+ */
+static void _dm_request(struct request_queue *q, struct bio *bio)
+{
+ int rw = bio_data_dir(bio);
+ struct mapped_device *md = q->queuedata;
+ int cpu;
+
+ down_read(&md->io_lock);
+
+ cpu = part_stat_lock();
+ part_stat_inc(cpu, &dm_disk(md)->part0, ios[rw]);
+ part_stat_add(cpu, &dm_disk(md)->part0, sectors[rw], bio_sectors(bio));
+ part_stat_unlock();
+
+ /* if we're suspended, we have to queue this io for later */
+ if (unlikely(test_bit(DMF_BLOCK_IO_FOR_SUSPEND, &md->flags))) {
+ up_read(&md->io_lock);
+
+ if (bio_rw(bio) != READA)
+ queue_io(md, bio);
+ else
+ bio_io_error(bio);
+ return;
+ }
+
+ __split_and_process_bio(md, bio);
+ up_read(&md->io_lock);
+ return;
+}
+
+static int dm_request_based(struct mapped_device *md)
+{
+ return blk_queue_stackable(md->queue);
+}
+
+static void dm_request(struct request_queue *q, struct bio *bio)
+{
+ struct mapped_device *md = q->queuedata;
+
+ if (dm_request_based(md))
+ blk_queue_bio(q, bio);
+ else
+ _dm_request(q, bio);
+}
+
+void dm_dispatch_request(struct request *rq)
+{
+ int r;
+
+ if (blk_queue_io_stat(rq->q))
+ rq->cmd_flags |= REQ_IO_STAT;
+
+ rq->start_time = jiffies;
+ r = blk_insert_cloned_request(rq->q, rq);
+ if (r)
+ dm_complete_request(rq, r);
+}
+EXPORT_SYMBOL_GPL(dm_dispatch_request);
+
+static void dm_rq_bio_destructor(struct bio *bio)
+{
+ struct dm_rq_clone_bio_info *info = bio->bi_private;
+ struct mapped_device *md = info->tio->md;
+
+ free_bio_info(info);
+ bio_free(bio, md->bs);
+}
+
+static int dm_rq_bio_constructor(struct bio *bio, struct bio *bio_orig,
+ void *data)
+{
+ struct dm_rq_target_io *tio = data;
+ struct mapped_device *md = tio->md;
+ struct dm_rq_clone_bio_info *info = alloc_bio_info(md);
+
+ if (!info)
+ return -ENOMEM;
+
+ info->orig = bio_orig;
+ info->tio = tio;
+ bio->bi_end_io = end_clone_bio;
+ bio->bi_private = info;
+ bio->bi_destructor = dm_rq_bio_destructor;
+
+ return 0;
+}
+
+static int setup_clone(struct request *clone, struct request *rq,
+ struct dm_rq_target_io *tio)
+{
+ int r;
+
+ r = blk_rq_prep_clone(clone, rq, tio->md->bs, GFP_ATOMIC,
+ dm_rq_bio_constructor, tio);
+ if (r)
+ return r;
+
+ clone->cmd = rq->cmd;
+ clone->cmd_len = rq->cmd_len;
+ clone->sense = rq->sense;
+ clone->buffer = rq->buffer;
+ clone->end_io = end_clone_request;
+ clone->end_io_data = tio;
+
+ return 0;
+}
+
+static struct request *clone_rq(struct request *rq, struct mapped_device *md,
+ gfp_t gfp_mask)
+{
+ struct request *clone;
+ struct dm_rq_target_io *tio;
+
+ tio = alloc_rq_tio(md, gfp_mask);
+ if (!tio)
+ return NULL;
+
+ tio->md = md;
+ tio->ti = NULL;
+ tio->orig = rq;
+ tio->error = 0;
+ memset(&tio->info, 0, sizeof(tio->info));
+
+ clone = &tio->clone;
+ if (setup_clone(clone, rq, tio)) {
+ /* -ENOMEM */
+ free_rq_tio(tio);
+ return NULL;
+ }
+
+ return clone;
+}
+
+/*
+ * Called with the queue lock held.
+ */
+static int dm_prep_fn(struct request_queue *q, struct request *rq)
+{
+ struct mapped_device *md = q->queuedata;
+ struct request *clone;
+
+ if (unlikely(rq->special)) {
+ DMWARN("Already has something in rq->special.");
+ return BLKPREP_KILL;
+ }
+
+ clone = clone_rq(rq, md, GFP_ATOMIC);
+ if (!clone)
+ return BLKPREP_DEFER;
+
+ rq->special = clone;
+ rq->cmd_flags |= REQ_DONTPREP;
+
+ return BLKPREP_OK;
+}
+
+/*
+ * Returns:
+ * 0 : the request has been processed (not requeued)
+ * !0 : the request has been requeued
+ */
+static int map_request(struct dm_target *ti, struct request *clone,
+ struct mapped_device *md)
+{
+ int r, requeued = 0;
+ struct dm_rq_target_io *tio = clone->end_io_data;
+
+ tio->ti = ti;
+ r = ti->type->map_rq(ti, clone, &tio->info);
+ switch (r) {
+ case DM_MAPIO_SUBMITTED:
+ /* The target has taken the I/O to submit by itself later */
+ break;
+ case DM_MAPIO_REMAPPED:
+ /* The target has remapped the I/O so dispatch it */
+ trace_block_rq_remap(clone->q, clone, disk_devt(dm_disk(md)),
+ blk_rq_pos(tio->orig));
+ dm_dispatch_request(clone);
+ break;
+ case DM_MAPIO_REQUEUE:
+ /* The target wants to requeue the I/O */
+ dm_requeue_unmapped_request(clone);
+ requeued = 1;
+ break;
+ default:
+ if (r > 0) {
+ DMWARN("unimplemented target map return value: %d", r);
+ BUG();
+ }
+
+ /* The target wants to complete the I/O */
+ dm_kill_unmapped_request(clone, r);
+ break;
+ }
+
+ return requeued;
+}
+
+static struct request *dm_start_request(struct mapped_device *md, struct request *orig)
+{
+ struct request *clone;
+
+ blk_start_request(orig);
+ clone = orig->special;
+ atomic_inc(&md->pending[rq_data_dir(clone)]);
+
+ /*
+ * Hold the md reference here for the in-flight I/O.
+ * We can't rely on the reference count by device opener,
+ * because the device may be closed during the request completion
+ * when all bios are completed.
+ * See the comment in rq_completed() too.
+ */
+ dm_get(md);
+
+ return clone;
+}
+
+/*
+ * q->request_fn for request-based dm.
+ * Called with the queue lock held.
+ */
+static void dm_request_fn(struct request_queue *q)
+{
+ struct mapped_device *md = q->queuedata;
+ struct dm_table *map = dm_get_live_table(md);
+ struct dm_target *ti;
+ struct request *rq, *clone;
+ sector_t pos;
+
+ /*
+ * For suspend, check blk_queue_stopped() and increment
+ * ->pending within a single queue_lock not to increment the
+ * number of in-flight I/Os after the queue is stopped in
+ * dm_suspend().
+ */
+ while (!blk_queue_stopped(q)) {
+ rq = blk_peek_request(q);
+ if (!rq)
+ goto delay_and_out;
+
+ /* always use block 0 to find the target for flushes for now */
+ pos = 0;
+ if (!(rq->cmd_flags & REQ_FLUSH))
+ pos = blk_rq_pos(rq);
+
+ ti = dm_table_find_target(map, pos);
+ if (!dm_target_is_valid(ti)) {
+ /*
+ * Must perform setup, that dm_done() requires,
+ * before calling dm_kill_unmapped_request
+ */
+ DMERR_LIMIT("request attempted access beyond the end of device");
+ clone = dm_start_request(md, rq);
+ dm_kill_unmapped_request(clone, -EIO);
+ continue;
+ }
+
+ if (ti->type->busy && ti->type->busy(ti))
+ goto delay_and_out;
+
+ clone = dm_start_request(md, rq);
+
+ spin_unlock(q->queue_lock);
+ if (map_request(ti, clone, md))
+ goto requeued;
+
+ BUG_ON_NONRT(!irqs_disabled());
+ spin_lock(q->queue_lock);
+ }
+
+ goto out;
+
+requeued:
+ BUG_ON_NONRT(!irqs_disabled());
+ spin_lock(q->queue_lock);
+
+delay_and_out:
+ blk_delay_queue(q, HZ / 10);
+out:
+ dm_table_put(map);
+}
+
+int dm_underlying_device_busy(struct request_queue *q)
+{
+ return blk_lld_busy(q);
+}
+EXPORT_SYMBOL_GPL(dm_underlying_device_busy);
+
+static int dm_lld_busy(struct request_queue *q)
+{
+ int r;
+ struct mapped_device *md = q->queuedata;
+ struct dm_table *map = dm_get_live_table(md);
+
+ if (!map || test_bit(DMF_BLOCK_IO_FOR_SUSPEND, &md->flags))
+ r = 1;
+ else
+ r = dm_table_any_busy_target(map);
+
+ dm_table_put(map);
+
+ return r;
+}
+
+static int dm_any_congested(void *congested_data, int bdi_bits)
+{
+ int r = bdi_bits;
+ struct mapped_device *md = congested_data;
+ struct dm_table *map;
+
+ if (!test_bit(DMF_BLOCK_IO_FOR_SUSPEND, &md->flags)) {
+ map = dm_get_live_table(md);
+ if (map) {
+ /*
+ * Request-based dm cares about only own queue for
+ * the query about congestion status of request_queue
+ */
+ if (dm_request_based(md))
+ r = md->queue->backing_dev_info.state &
+ bdi_bits;
+ else
+ r = dm_table_any_congested(map, bdi_bits);
+
+ dm_table_put(map);
+ }
+ }
+
+ return r;
+}
+
+/*-----------------------------------------------------------------
+ * An IDR is used to keep track of allocated minor numbers.
+ *---------------------------------------------------------------*/
+static void free_minor(int minor)
+{
+ spin_lock(&_minor_lock);
+ idr_remove(&_minor_idr, minor);
+ spin_unlock(&_minor_lock);
+}
+
+/*
+ * See if the device with a specific minor # is free.
+ */
+static int specific_minor(int minor)
+{
+ int r, m;
+
+ if (minor >= (1 << MINORBITS))
+ return -EINVAL;
+
+ r = idr_pre_get(&_minor_idr, GFP_KERNEL);
+ if (!r)
+ return -ENOMEM;
+
+ spin_lock(&_minor_lock);
+
+ if (idr_find(&_minor_idr, minor)) {
+ r = -EBUSY;
+ goto out;
+ }
+
+ r = idr_get_new_above(&_minor_idr, MINOR_ALLOCED, minor, &m);
+ if (r)
+ goto out;
+
+ if (m != minor) {
+ idr_remove(&_minor_idr, m);
+ r = -EBUSY;
+ goto out;
+ }
+
+out:
+ spin_unlock(&_minor_lock);
+ return r;
+}
+
+static int next_free_minor(int *minor)
+{
+ int r, m;
+
+ r = idr_pre_get(&_minor_idr, GFP_KERNEL);
+ if (!r)
+ return -ENOMEM;
+
+ spin_lock(&_minor_lock);
+
+ r = idr_get_new(&_minor_idr, MINOR_ALLOCED, &m);
+ if (r)
+ goto out;
+
+ if (m >= (1 << MINORBITS)) {
+ idr_remove(&_minor_idr, m);
+ r = -ENOSPC;
+ goto out;
+ }
+
+ *minor = m;
+
+out:
+ spin_unlock(&_minor_lock);
+ return r;
+}
+
+static const struct block_device_operations dm_blk_dops;
+
+static void dm_wq_work(struct work_struct *work);
+
+static void dm_init_md_queue(struct mapped_device *md)
+{
+ /*
+ * Request-based dm devices cannot be stacked on top of bio-based dm
+ * devices. The type of this dm device has not been decided yet.
+ * The type is decided at the first table loading time.
+ * To prevent problematic device stacking, clear the queue flag
+ * for request stacking support until then.
+ *
+ * This queue is new, so no concurrency on the queue_flags.
+ */
+ queue_flag_clear_unlocked(QUEUE_FLAG_STACKABLE, md->queue);
+
+ md->queue->queuedata = md;
+ md->queue->backing_dev_info.congested_fn = dm_any_congested;
+ md->queue->backing_dev_info.congested_data = md;
+ blk_queue_make_request(md->queue, dm_request);
+ blk_queue_bounce_limit(md->queue, BLK_BOUNCE_ANY);
+ blk_queue_merge_bvec(md->queue, dm_merge_bvec);
+}
+
+/*
+ * Allocate and initialise a blank device with a given minor.
+ */
+static struct mapped_device *alloc_dev(int minor)
+{
+ int r;
+ struct mapped_device *md = kzalloc(sizeof(*md), GFP_KERNEL);
+ void *old_md;
+
+ if (!md) {
+ DMWARN("unable to allocate device, out of memory.");
+ return NULL;
+ }
+
+ if (!try_module_get(THIS_MODULE))
+ goto bad_module_get;
+
+ /* get a minor number for the dev */
+ if (minor == DM_ANY_MINOR)
+ r = next_free_minor(&minor);
+ else
+ r = specific_minor(minor);
+ if (r < 0)
+ goto bad_minor;
+
+ md->type = DM_TYPE_NONE;
+ init_rwsem(&md->io_lock);
+ mutex_init(&md->suspend_lock);
+ mutex_init(&md->type_lock);
+ spin_lock_init(&md->deferred_lock);
+ rwlock_init(&md->map_lock);
+ atomic_set(&md->holders, 1);
+ atomic_set(&md->open_count, 0);
+ atomic_set(&md->event_nr, 0);
+ atomic_set(&md->uevent_seq, 0);
+ INIT_LIST_HEAD(&md->uevent_list);
+ spin_lock_init(&md->uevent_lock);
+
+ md->queue = blk_alloc_queue(GFP_KERNEL);
+ if (!md->queue)
+ goto bad_queue;
+
+ dm_init_md_queue(md);
+
+ md->disk = alloc_disk(1);
+ if (!md->disk)
+ goto bad_disk;
+
+ atomic_set(&md->pending[0], 0);
+ atomic_set(&md->pending[1], 0);
+ init_waitqueue_head(&md->wait);
+ INIT_WORK(&md->work, dm_wq_work);
+ init_waitqueue_head(&md->eventq);
+ init_completion(&md->kobj_holder.completion);
+
+ md->disk->major = _major;
+ md->disk->first_minor = minor;
+ md->disk->fops = &dm_blk_dops;
+ md->disk->queue = md->queue;
+ md->disk->private_data = md;
+ sprintf(md->disk->disk_name, "dm-%d", minor);
+ add_disk(md->disk);
+ format_dev_t(md->name, MKDEV(_major, minor));
+
+ md->wq = alloc_workqueue("kdmflush",
+ WQ_NON_REENTRANT | WQ_MEM_RECLAIM, 0);
+ if (!md->wq)
+ goto bad_thread;
+
+ md->bdev = bdget_disk(md->disk, 0);
+ if (!md->bdev)
+ goto bad_bdev;
+
+ bio_init(&md->flush_bio);
+ md->flush_bio.bi_bdev = md->bdev;
+ md->flush_bio.bi_rw = WRITE_FLUSH;
+
+ /* Populate the mapping, nobody knows we exist yet */
+ spin_lock(&_minor_lock);
+ old_md = idr_replace(&_minor_idr, md, minor);
+ spin_unlock(&_minor_lock);
+
+ BUG_ON(old_md != MINOR_ALLOCED);
+
+ return md;
+
+bad_bdev:
+ destroy_workqueue(md->wq);
+bad_thread:
+ del_gendisk(md->disk);
+ put_disk(md->disk);
+bad_disk:
+ blk_cleanup_queue(md->queue);
+bad_queue:
+ free_minor(minor);
+bad_minor:
+ module_put(THIS_MODULE);
+bad_module_get:
+ kfree(md);
+ return NULL;
+}
+
+static void unlock_fs(struct mapped_device *md);
+
+static void free_dev(struct mapped_device *md)
+{
+ int minor = MINOR(disk_devt(md->disk));
+
+ unlock_fs(md);
+ bdput(md->bdev);
+ destroy_workqueue(md->wq);
+ if (md->tio_pool)
+ mempool_destroy(md->tio_pool);
+ if (md->io_pool)
+ mempool_destroy(md->io_pool);
+ if (md->bs)
+ bioset_free(md->bs);
+ blk_integrity_unregister(md->disk);
+ del_gendisk(md->disk);
+ free_minor(minor);
+
+ spin_lock(&_minor_lock);
+ md->disk->private_data = NULL;
+ spin_unlock(&_minor_lock);
+
+ put_disk(md->disk);
+ blk_cleanup_queue(md->queue);
+ module_put(THIS_MODULE);
+ kfree(md);
+}
+
+static void __bind_mempools(struct mapped_device *md, struct dm_table *t)
+{
+ struct dm_md_mempools *p;
+
+ if (md->io_pool && md->tio_pool && md->bs)
+ /* the md already has necessary mempools */
+ goto out;
+
+ p = dm_table_get_md_mempools(t);
+ BUG_ON(!p || md->io_pool || md->tio_pool || md->bs);
+
+ md->io_pool = p->io_pool;
+ p->io_pool = NULL;
+ md->tio_pool = p->tio_pool;
+ p->tio_pool = NULL;
+ md->bs = p->bs;
+ p->bs = NULL;
+
+out:
+ /* mempool bind completed, now no need any mempools in the table */
+ dm_table_free_md_mempools(t);
+}
+
+/*
+ * Bind a table to the device.
+ */
+static void event_callback(void *context)
+{
+ unsigned long flags;
+ LIST_HEAD(uevents);
+ struct mapped_device *md = (struct mapped_device *) context;
+
+ spin_lock_irqsave(&md->uevent_lock, flags);
+ list_splice_init(&md->uevent_list, &uevents);
+ spin_unlock_irqrestore(&md->uevent_lock, flags);
+
+ dm_send_uevents(&uevents, &disk_to_dev(md->disk)->kobj);
+
+ atomic_inc(&md->event_nr);
+ wake_up(&md->eventq);
+}
+
+/*
+ * Protected by md->suspend_lock obtained by dm_swap_table().
+ */
+static void __set_size(struct mapped_device *md, sector_t size)
+{
+ set_capacity(md->disk, size);
+
+ i_size_write(md->bdev->bd_inode, (loff_t)size << SECTOR_SHIFT);
+}
+
+/*
+ * Return 1 if the queue has a compulsory merge_bvec_fn function.
+ *
+ * If this function returns 0, then the device is either a non-dm
+ * device without a merge_bvec_fn, or it is a dm device that is
+ * able to split any bios it receives that are too big.
+ */
+int dm_queue_merge_is_compulsory(struct request_queue *q)
+{
+ struct mapped_device *dev_md;
+
+ if (!q->merge_bvec_fn)
+ return 0;
+
+ if (q->make_request_fn == dm_request) {
+ dev_md = q->queuedata;
+ if (test_bit(DMF_MERGE_IS_OPTIONAL, &dev_md->flags))
+ return 0;
+ }
+
+ return 1;
+}
+
+static int dm_device_merge_is_compulsory(struct dm_target *ti,
+ struct dm_dev *dev, sector_t start,
+ sector_t len, void *data)
+{
+ struct block_device *bdev = dev->bdev;
+ struct request_queue *q = bdev_get_queue(bdev);
+
+ return dm_queue_merge_is_compulsory(q);
+}
+
+/*
+ * Return 1 if it is acceptable to ignore merge_bvec_fn based
+ * on the properties of the underlying devices.
+ */
+static int dm_table_merge_is_optional(struct dm_table *table)
+{
+ unsigned i = 0;
+ struct dm_target *ti;
+
+ while (i < dm_table_get_num_targets(table)) {
+ ti = dm_table_get_target(table, i++);
+
+ if (ti->type->iterate_devices &&
+ ti->type->iterate_devices(ti, dm_device_merge_is_compulsory, NULL))
+ return 0;
+ }
+
+ return 1;
+}
+
+/*
+ * Returns old map, which caller must destroy.
+ */
+static struct dm_table *__bind(struct mapped_device *md, struct dm_table *t,
+ struct queue_limits *limits)
+{
+ struct dm_table *old_map;
+ struct request_queue *q = md->queue;
+ sector_t size;
+ unsigned long flags;
+ int merge_is_optional;
+
+ size = dm_table_get_size(t);
+
+ /*
+ * Wipe any geometry if the size of the table changed.
+ */
+ if (size != get_capacity(md->disk))
+ memset(&md->geometry, 0, sizeof(md->geometry));
+
+ __set_size(md, size);
+
+ dm_table_event_callback(t, event_callback, md);
+
+ /*
+ * The queue hasn't been stopped yet, if the old table type wasn't
+ * for request-based during suspension. So stop it to prevent
+ * I/O mapping before resume.
+ * This must be done before setting the queue restrictions,
+ * because request-based dm may be run just after the setting.
+ */
+ if (dm_table_request_based(t) && !blk_queue_stopped(q))
+ stop_queue(q);
+
+ __bind_mempools(md, t);
+
+ merge_is_optional = dm_table_merge_is_optional(t);
+
+ write_lock_irqsave(&md->map_lock, flags);
+ old_map = md->map;
+ md->map = t;
+ md->immutable_target_type = dm_table_get_immutable_target_type(t);
+
+ dm_table_set_restrictions(t, q, limits);
+ if (merge_is_optional)
+ set_bit(DMF_MERGE_IS_OPTIONAL, &md->flags);
+ else
+ clear_bit(DMF_MERGE_IS_OPTIONAL, &md->flags);
+ write_unlock_irqrestore(&md->map_lock, flags);
+
+ return old_map;
+}
+
+/*
+ * Returns unbound table for the caller to free.
+ */
+static struct dm_table *__unbind(struct mapped_device *md)
+{
+ struct dm_table *map = md->map;
+ unsigned long flags;
+
+ if (!map)
+ return NULL;
+
+ dm_table_event_callback(map, NULL, NULL);
+ write_lock_irqsave(&md->map_lock, flags);
+ md->map = NULL;
+ write_unlock_irqrestore(&md->map_lock, flags);
+
+ return map;
+}
+
+/*
+ * Constructor for a new device.
+ */
+int dm_create(int minor, struct mapped_device **result)
+{
+ struct mapped_device *md;
+
+ md = alloc_dev(minor);
+ if (!md)
+ return -ENXIO;
+
+ dm_sysfs_init(md);
+
+ *result = md;
+ return 0;
+}
+
+/*
+ * Functions to manage md->type.
+ * All are required to hold md->type_lock.
+ */
+void dm_lock_md_type(struct mapped_device *md)
+{
+ mutex_lock(&md->type_lock);
+}
+
+void dm_unlock_md_type(struct mapped_device *md)
+{
+ mutex_unlock(&md->type_lock);
+}
+
+void dm_set_md_type(struct mapped_device *md, unsigned type)
+{
+ md->type = type;
+}
+
+unsigned dm_get_md_type(struct mapped_device *md)
+{
+ return md->type;
+}
+
+struct target_type *dm_get_immutable_target_type(struct mapped_device *md)
+{
+ return md->immutable_target_type;
+}
+
+/*
+ * Fully initialize a request-based queue (->elevator, ->request_fn, etc).
+ */
+static int dm_init_request_based_queue(struct mapped_device *md)
+{
+ struct request_queue *q = NULL;
+
+ if (md->queue->elevator)
+ return 1;
+
+ /* Fully initialize the queue */
+ q = blk_init_allocated_queue(md->queue, dm_request_fn, NULL);
+ if (!q)
+ return 0;
+
+ md->queue = q;
+ dm_init_md_queue(md);
+ blk_queue_softirq_done(md->queue, dm_softirq_done);
+ blk_queue_prep_rq(md->queue, dm_prep_fn);
+ blk_queue_lld_busy(md->queue, dm_lld_busy);
+
+ elv_register_queue(md->queue);
+
+ return 1;
+}
+
+/*
+ * Setup the DM device's queue based on md's type
+ */
+int dm_setup_md_queue(struct mapped_device *md)
+{
+ if ((dm_get_md_type(md) == DM_TYPE_REQUEST_BASED) &&
+ !dm_init_request_based_queue(md)) {
+ DMWARN("Cannot initialize queue for request-based mapped device");
+ return -EINVAL;
+ }
+
+ return 0;
+}
+
+struct mapped_device *dm_get_md(dev_t dev)
+{
+ struct mapped_device *md;
+ unsigned minor = MINOR(dev);
+
+ if (MAJOR(dev) != _major || minor >= (1 << MINORBITS))
+ return NULL;
+
+ spin_lock(&_minor_lock);
+
+ md = idr_find(&_minor_idr, minor);
+ if (md) {
+ if ((md == MINOR_ALLOCED ||
+ (MINOR(disk_devt(dm_disk(md))) != minor) ||
+ dm_deleting_md(md) ||
+ test_bit(DMF_FREEING, &md->flags))) {
+ md = NULL;
+ goto out;
+ }
+ dm_get(md);
+ }
+
+out:
+ spin_unlock(&_minor_lock);
+
+ return md;
+}
+EXPORT_SYMBOL_GPL(dm_get_md);
+
+void *dm_get_mdptr(struct mapped_device *md)
+{
+ return md->interface_ptr;
+}
+
+void dm_set_mdptr(struct mapped_device *md, void *ptr)
+{
+ md->interface_ptr = ptr;
+}
+
+void dm_get(struct mapped_device *md)
+{
+ atomic_inc(&md->holders);
+ BUG_ON(test_bit(DMF_FREEING, &md->flags));
+}
+
+const char *dm_device_name(struct mapped_device *md)
+{
+ return md->name;
+}
+EXPORT_SYMBOL_GPL(dm_device_name);
+
+static void __dm_destroy(struct mapped_device *md, bool wait)
+{
+ struct dm_table *map;
+
+ might_sleep();
+
+ spin_lock(&_minor_lock);
+ map = dm_get_live_table(md);
+ idr_replace(&_minor_idr, MINOR_ALLOCED, MINOR(disk_devt(dm_disk(md))));
+ set_bit(DMF_FREEING, &md->flags);
+ spin_unlock(&_minor_lock);
+
+ /*
+ * Take suspend_lock so that presuspend and postsuspend methods
+ * do not race with internal suspend.
+ */
+ mutex_lock(&md->suspend_lock);
+ if (!dm_suspended_md(md)) {
+ dm_table_presuspend_targets(map);
+ dm_table_postsuspend_targets(map);
+ }
+ mutex_unlock(&md->suspend_lock);
+
+ /*
+ * Rare, but there may be I/O requests still going to complete,
+ * for example. Wait for all references to disappear.
+ * No one should increment the reference count of the mapped_device,
+ * after the mapped_device state becomes DMF_FREEING.
+ */
+ if (wait)
+ while (atomic_read(&md->holders))
+ msleep(1);
+ else if (atomic_read(&md->holders))
+ DMWARN("%s: Forcibly removing mapped_device still in use! (%d users)",
+ dm_device_name(md), atomic_read(&md->holders));
+
+ dm_sysfs_exit(md);
+ dm_table_put(map);
+ dm_table_destroy(__unbind(md));
+ free_dev(md);
+}
+
+void dm_destroy(struct mapped_device *md)
+{
+ __dm_destroy(md, true);
+}
+
+void dm_destroy_immediate(struct mapped_device *md)
+{
+ __dm_destroy(md, false);
+}
+
+void dm_put(struct mapped_device *md)
+{
+ atomic_dec(&md->holders);
+}
+EXPORT_SYMBOL_GPL(dm_put);
+
+static int dm_wait_for_completion(struct mapped_device *md, int interruptible)
+{
+ int r = 0;
+ DECLARE_WAITQUEUE(wait, current);
+
+ add_wait_queue(&md->wait, &wait);
+
+ while (1) {
+ set_current_state(interruptible);
+
+ if (!md_in_flight(md))
+ break;
+
+ if (interruptible == TASK_INTERRUPTIBLE &&
+ signal_pending(current)) {
+ r = -EINTR;
+ break;
+ }
+
+ io_schedule();
+ }
+ set_current_state(TASK_RUNNING);
+
+ remove_wait_queue(&md->wait, &wait);
+
+ return r;
+}
+
+/*
+ * Process the deferred bios
+ */
+static void dm_wq_work(struct work_struct *work)
+{
+ struct mapped_device *md = container_of(work, struct mapped_device,
+ work);
+ struct bio *c;
+
+ down_read(&md->io_lock);
+
+ while (!test_bit(DMF_BLOCK_IO_FOR_SUSPEND, &md->flags)) {
+ spin_lock_irq(&md->deferred_lock);
+ c = bio_list_pop(&md->deferred);
+ spin_unlock_irq(&md->deferred_lock);
+
+ if (!c)
+ break;
+
+ up_read(&md->io_lock);
+
+ if (dm_request_based(md))
+ generic_make_request(c);
+ else
+ __split_and_process_bio(md, c);
+
+ down_read(&md->io_lock);
+ }
+
+ up_read(&md->io_lock);
+}
+
+static void dm_queue_flush(struct mapped_device *md)
+{
+ clear_bit(DMF_BLOCK_IO_FOR_SUSPEND, &md->flags);
+ smp_mb__after_clear_bit();
+ queue_work(md->wq, &md->work);
+}
+
+/*
+ * Swap in a new table, returning the old one for the caller to destroy.
+ */
+struct dm_table *dm_swap_table(struct mapped_device *md, struct dm_table *table)
+{
+ struct dm_table *map = ERR_PTR(-EINVAL);
+ struct queue_limits limits;
+ int r;
+
+ mutex_lock(&md->suspend_lock);
+
+ /* device must be suspended */
+ if (!dm_suspended_md(md))
+ goto out;
+
+ r = dm_calculate_queue_limits(table, &limits);
+ if (r) {
+ map = ERR_PTR(r);
+ goto out;
+ }
+
+ map = __bind(md, table, &limits);
+
+out:
+ mutex_unlock(&md->suspend_lock);
+ return map;
+}
+
+/*
+ * Functions to lock and unlock any filesystem running on the
+ * device.
+ */
+static int lock_fs(struct mapped_device *md)
+{
+ int r;
+
+ WARN_ON(md->frozen_sb);
+
+ md->frozen_sb = freeze_bdev(md->bdev);
+ if (IS_ERR(md->frozen_sb)) {
+ r = PTR_ERR(md->frozen_sb);
+ md->frozen_sb = NULL;
+ return r;
+ }
+
+ set_bit(DMF_FROZEN, &md->flags);
+
+ return 0;
+}
+
+static void unlock_fs(struct mapped_device *md)
+{
+ if (!test_bit(DMF_FROZEN, &md->flags))
+ return;
+
+ thaw_bdev(md->bdev, md->frozen_sb);
+ md->frozen_sb = NULL;
+ clear_bit(DMF_FROZEN, &md->flags);
+}
+
+/*
+ * We need to be able to change a mapping table under a mounted
+ * filesystem. For example we might want to move some data in
+ * the background. Before the table can be swapped with
+ * dm_bind_table, dm_suspend must be called to flush any in
+ * flight bios and ensure that any further io gets deferred.
+ */
+/*
+ * Suspend mechanism in request-based dm.
+ *
+ * 1. Flush all I/Os by lock_fs() if needed.
+ * 2. Stop dispatching any I/O by stopping the request_queue.
+ * 3. Wait for all in-flight I/Os to be completed or requeued.
+ *
+ * To abort suspend, start the request_queue.
+ */
+int dm_suspend(struct mapped_device *md, unsigned suspend_flags)
+{
+ struct dm_table *map = NULL;
+ int r = 0;
+ int do_lockfs = suspend_flags & DM_SUSPEND_LOCKFS_FLAG ? 1 : 0;
+ int noflush = suspend_flags & DM_SUSPEND_NOFLUSH_FLAG ? 1 : 0;
+
+ mutex_lock(&md->suspend_lock);
+
+ if (dm_suspended_md(md)) {
+ r = -EINVAL;
+ goto out_unlock;
+ }
+
+ map = dm_get_live_table(md);
+
+ /*
+ * DMF_NOFLUSH_SUSPENDING must be set before presuspend.
+ * This flag is cleared before dm_suspend returns.
+ */
+ if (noflush)
+ set_bit(DMF_NOFLUSH_SUSPENDING, &md->flags);
+
+ /* This does not get reverted if there's an error later. */
+ dm_table_presuspend_targets(map);
+
+ /*
+ * Flush I/O to the device.
+ * Any I/O submitted after lock_fs() may not be flushed.
+ * noflush takes precedence over do_lockfs.
+ * (lock_fs() flushes I/Os and waits for them to complete.)
+ */
+ if (!noflush && do_lockfs) {
+ r = lock_fs(md);
+ if (r)
+ goto out;
+ }
+
+ /*
+ * Here we must make sure that no processes are submitting requests
+ * to target drivers i.e. no one may be executing
+ * __split_and_process_bio. This is called from dm_request and
+ * dm_wq_work.
+ *
+ * To get all processes out of __split_and_process_bio in dm_request,
+ * we take the write lock. To prevent any process from reentering
+ * __split_and_process_bio from dm_request and quiesce the thread
+ * (dm_wq_work), we set BMF_BLOCK_IO_FOR_SUSPEND and call
+ * flush_workqueue(md->wq).
+ */
+ down_write(&md->io_lock);
+ set_bit(DMF_BLOCK_IO_FOR_SUSPEND, &md->flags);
+ up_write(&md->io_lock);
+
+ /*
+ * Stop md->queue before flushing md->wq in case request-based
+ * dm defers requests to md->wq from md->queue.
+ */
+ if (dm_request_based(md))
+ stop_queue(md->queue);
+
+ flush_workqueue(md->wq);
+
+ /*
+ * At this point no more requests are entering target request routines.
+ * We call dm_wait_for_completion to wait for all existing requests
+ * to finish.
+ */
+ r = dm_wait_for_completion(md, TASK_INTERRUPTIBLE);
+
+ down_write(&md->io_lock);
+ if (noflush)
+ clear_bit(DMF_NOFLUSH_SUSPENDING, &md->flags);
+ up_write(&md->io_lock);
+
+ /* were we interrupted ? */
+ if (r < 0) {
+ dm_queue_flush(md);
+
+ if (dm_request_based(md))
+ start_queue(md->queue);
+
+ unlock_fs(md);
+ goto out; /* pushback list is already flushed, so skip flush */
+ }
+
+ /*
+ * If dm_wait_for_completion returned 0, the device is completely
+ * quiescent now. There is no request-processing activity. All new
+ * requests are being added to md->deferred list.
+ */
+
+ set_bit(DMF_SUSPENDED, &md->flags);
+
+ dm_table_postsuspend_targets(map);
+
+out:
+ dm_table_put(map);
+
+out_unlock:
+ mutex_unlock(&md->suspend_lock);
+ return r;
+}
+
+int dm_resume(struct mapped_device *md)
+{
+ int r = -EINVAL;
+ struct dm_table *map = NULL;
+
+ mutex_lock(&md->suspend_lock);
+ if (!dm_suspended_md(md))
+ goto out;
+
+ map = dm_get_live_table(md);
+ if (!map || !dm_table_get_size(map))
+ goto out;
+
+ r = dm_table_resume_targets(map);
+ if (r)
+ goto out;
+
+ dm_queue_flush(md);
+
+ /*
+ * Flushing deferred I/Os must be done after targets are resumed
+ * so that mapping of targets can work correctly.
+ * Request-based dm is queueing the deferred I/Os in its request_queue.
+ */
+ if (dm_request_based(md))
+ start_queue(md->queue);
+
+ unlock_fs(md);
+
+ clear_bit(DMF_SUSPENDED, &md->flags);
+
+ r = 0;
+out:
+ dm_table_put(map);
+ mutex_unlock(&md->suspend_lock);
+
+ return r;
+}
+
+/*-----------------------------------------------------------------
+ * Event notification.
+ *---------------------------------------------------------------*/
+int dm_kobject_uevent(struct mapped_device *md, enum kobject_action action,
+ unsigned cookie)
+{
+ char udev_cookie[DM_COOKIE_LENGTH];
+ char *envp[] = { udev_cookie, NULL };
+
+ if (!cookie)
+ return kobject_uevent(&disk_to_dev(md->disk)->kobj, action);
+ else {
+ snprintf(udev_cookie, DM_COOKIE_LENGTH, "%s=%u",
+ DM_COOKIE_ENV_VAR_NAME, cookie);
+ return kobject_uevent_env(&disk_to_dev(md->disk)->kobj,
+ action, envp);
+ }
+}
+
+uint32_t dm_next_uevent_seq(struct mapped_device *md)
+{
+ return atomic_add_return(1, &md->uevent_seq);
+}
+
+uint32_t dm_get_event_nr(struct mapped_device *md)
+{
+ return atomic_read(&md->event_nr);
+}
+
+int dm_wait_event(struct mapped_device *md, int event_nr)
+{
+ return wait_event_interruptible(md->eventq,
+ (event_nr != atomic_read(&md->event_nr)));
+}
+
+void dm_uevent_add(struct mapped_device *md, struct list_head *elist)
+{
+ unsigned long flags;
+
+ spin_lock_irqsave(&md->uevent_lock, flags);
+ list_add(elist, &md->uevent_list);
+ spin_unlock_irqrestore(&md->uevent_lock, flags);
+}
+
+/*
+ * The gendisk is only valid as long as you have a reference
+ * count on 'md'.
+ */
+struct gendisk *dm_disk(struct mapped_device *md)
+{
+ return md->disk;
+}
+
+struct kobject *dm_kobject(struct mapped_device *md)
+{
+ return &md->kobj_holder.kobj;
+}
+
+struct mapped_device *dm_get_from_kobject(struct kobject *kobj)
+{
+ struct mapped_device *md;
+
+ md = container_of(kobj, struct mapped_device, kobj_holder.kobj);
+
+ if (test_bit(DMF_FREEING, &md->flags) ||
+ dm_deleting_md(md))
+ return NULL;
+
+ dm_get(md);
+ return md;
+}
+
+int dm_suspended_md(struct mapped_device *md)
+{
+ return test_bit(DMF_SUSPENDED, &md->flags);
+}
+
+int dm_suspended(struct dm_target *ti)
+{
+ return dm_suspended_md(dm_table_get_md(ti->table));
+}
+EXPORT_SYMBOL_GPL(dm_suspended);
+
+int dm_noflush_suspending(struct dm_target *ti)
+{
+ return __noflush_suspending(dm_table_get_md(ti->table));
+}
+EXPORT_SYMBOL_GPL(dm_noflush_suspending);
+
+struct dm_md_mempools *dm_alloc_md_mempools(unsigned type, unsigned integrity)
+{
+ struct dm_md_mempools *pools = kmalloc(sizeof(*pools), GFP_KERNEL);
+ unsigned int pool_size = (type == DM_TYPE_BIO_BASED) ? 16 : MIN_IOS;
+
+ if (!pools)
+ return NULL;
+
+ pools->io_pool = (type == DM_TYPE_BIO_BASED) ?
+ mempool_create_slab_pool(MIN_IOS, _io_cache) :
+ mempool_create_slab_pool(MIN_IOS, _rq_bio_info_cache);
+ if (!pools->io_pool)
+ goto free_pools_and_out;
+
+ pools->tio_pool = (type == DM_TYPE_BIO_BASED) ?
+ mempool_create_slab_pool(MIN_IOS, _tio_cache) :
+ mempool_create_slab_pool(MIN_IOS, _rq_tio_cache);
+ if (!pools->tio_pool)
+ goto free_io_pool_and_out;
+
+ pools->bs = bioset_create(pool_size, 0);
+ if (!pools->bs)
+ goto free_tio_pool_and_out;
+
+ if (integrity && bioset_integrity_create(pools->bs, pool_size))
+ goto free_bioset_and_out;
+
+ return pools;
+
+free_bioset_and_out:
+ bioset_free(pools->bs);
+
+free_tio_pool_and_out:
+ mempool_destroy(pools->tio_pool);
+
+free_io_pool_and_out:
+ mempool_destroy(pools->io_pool);
+
+free_pools_and_out:
+ kfree(pools);
+
+ return NULL;
+}
+
+void dm_free_md_mempools(struct dm_md_mempools *pools)
+{
+ if (!pools)
+ return;
+
+ if (pools->io_pool)
+ mempool_destroy(pools->io_pool);
+
+ if (pools->tio_pool)
+ mempool_destroy(pools->tio_pool);
+
+ if (pools->bs)
+ bioset_free(pools->bs);
+
+ kfree(pools);
+}
+
+static const struct block_device_operations dm_blk_dops = {
+ .open = dm_blk_open,
+ .release = dm_blk_close,
+ .ioctl = dm_blk_ioctl,
+ .getgeo = dm_blk_getgeo,
+ .owner = THIS_MODULE
+};
+
+EXPORT_SYMBOL(dm_get_mapinfo);
+
+/*
+ * module hooks
+ */
+module_init(dm_init);
+module_exit(dm_exit);
+
+module_param(major, uint, 0);
+MODULE_PARM_DESC(major, "The major number of the device mapper");
+MODULE_DESCRIPTION(DM_NAME " driver");
+MODULE_AUTHOR("Joe Thornber <dm-devel@redhat.com>");
+MODULE_LICENSE("GPL");