dm cache: bump the target version
[cascardo/linux.git] / drivers / md / dm.c
index 5df4048..70d5b82 100644 (file)
@@ -106,14 +106,6 @@ struct dm_rq_clone_bio_info {
        struct bio clone;
 };
 
-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)
 
 /*
@@ -128,29 +120,19 @@ EXPORT_SYMBOL_GPL(dm_get_rq_mapinfo);
 #define DMF_DEFERRED_REMOVE 6
 #define DMF_SUSPENDED_INTERNALLY 7
 
-/*
- * A dummy definition to make RCU happy.
- * struct dm_table should never be dereferenced in this file.
- */
-struct dm_table {
-       int undefined__;
-};
-
 /*
  * Work processed by per-device workqueue.
  */
 struct mapped_device {
        struct srcu_struct io_barrier;
        struct mutex suspend_lock;
-       atomic_t holders;
-       atomic_t open_count;
 
        /*
-        * The current mapping.
+        * The current mapping (struct dm_table *).
         * Use dm_get_live_table{_fast} or take suspend_lock for
         * dereference.
         */
-       struct dm_table __rcu *map;
+       void __rcu *map;
 
        struct list_head table_devices;
        struct mutex table_devices_lock;
@@ -158,10 +140,16 @@ struct mapped_device {
        unsigned long flags;
 
        struct request_queue *queue;
+       int numa_node_id;
+
        unsigned type;
        /* Protect queue and type against concurrent access. */
        struct mutex type_lock;
 
+       atomic_t holders;
+       atomic_t open_count;
+
+       struct dm_target *immutable_target;
        struct target_type *immutable_target_type;
 
        struct gendisk *disk;
@@ -175,8 +163,20 @@ struct mapped_device {
        atomic_t pending[2];
        wait_queue_head_t wait;
        struct work_struct work;
-       struct bio_list deferred;
        spinlock_t deferred_lock;
+       struct bio_list deferred;
+
+       /*
+        * Event handling.
+        */
+       wait_queue_head_t eventq;
+       atomic_t event_nr;
+       atomic_t uevent_seq;
+       struct list_head uevent_list;
+       spinlock_t uevent_lock; /* Protect access to uevent_list */
+
+       /* the number of internal suspends */
+       unsigned internal_suspend_count;
 
        /*
         * Processing queue (flush)
@@ -191,33 +191,22 @@ struct mapped_device {
 
        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;
 
+       struct block_device *bdev;
+
        /* kobject and completion */
        struct dm_kobject_holder kobj_holder;
 
        /* zero-length flush that will be cloned and submitted to targets */
        struct bio flush_bio;
 
-       /* the number of internal suspends */
-       unsigned internal_suspend_count;
-
        struct dm_stats stats;
 
        struct kthread_worker kworker;
@@ -230,8 +219,9 @@ struct mapped_device {
        ktime_t last_rq_start_time;
 
        /* for blk-mq request-based DM support */
-       struct blk_mq_tag_set tag_set;
-       bool use_blk_mq;
+       struct blk_mq_tag_set *tag_set;
+       bool use_blk_mq:1;
+       bool init_tio_pdu:1;
 };
 
 #ifdef CONFIG_DM_MQ_DEFAULT
@@ -240,10 +230,19 @@ static bool use_blk_mq = true;
 static bool use_blk_mq = false;
 #endif
 
+#define DM_MQ_NR_HW_QUEUES 1
+#define DM_MQ_QUEUE_DEPTH 2048
+#define DM_NUMA_NODE NUMA_NO_NODE
+
+static unsigned dm_mq_nr_hw_queues = DM_MQ_NR_HW_QUEUES;
+static unsigned dm_mq_queue_depth = DM_MQ_QUEUE_DEPTH;
+static int dm_numa_node = DM_NUMA_NODE;
+
 bool dm_use_blk_mq(struct mapped_device *md)
 {
        return md->use_blk_mq;
 }
+EXPORT_SYMBOL_GPL(dm_use_blk_mq);
 
 /*
  * For mempools pre-allocation at the table loading time.
@@ -277,6 +276,27 @@ static unsigned reserved_bio_based_ios = RESERVED_BIO_BASED_IOS;
  */
 static unsigned reserved_rq_based_ios = RESERVED_REQUEST_BASED_IOS;
 
+static int __dm_get_module_param_int(int *module_param, int min, int max)
+{
+       int param = ACCESS_ONCE(*module_param);
+       int modified_param = 0;
+       bool modified = true;
+
+       if (param < min)
+               modified_param = min;
+       else if (param > max)
+               modified_param = max;
+       else
+               modified = false;
+
+       if (modified) {
+               (void)cmpxchg(module_param, param, modified_param);
+               param = modified_param;
+       }
+
+       return param;
+}
+
 static unsigned __dm_get_module_param(unsigned *module_param,
                                      unsigned def, unsigned max)
 {
@@ -310,6 +330,23 @@ unsigned dm_get_reserved_rq_based_ios(void)
 }
 EXPORT_SYMBOL_GPL(dm_get_reserved_rq_based_ios);
 
+static unsigned dm_get_blk_mq_nr_hw_queues(void)
+{
+       return __dm_get_module_param(&dm_mq_nr_hw_queues, 1, 32);
+}
+
+static unsigned dm_get_blk_mq_queue_depth(void)
+{
+       return __dm_get_module_param(&dm_mq_queue_depth,
+                                    DM_MQ_QUEUE_DEPTH, BLK_MQ_MAX_DEPTH);
+}
+
+static unsigned dm_get_numa_node(void)
+{
+       return __dm_get_module_param_int(&dm_numa_node,
+                                        DM_NUMA_NODE, num_online_nodes() - 1);
+}
+
 static int __init local_init(void)
 {
        int r = -ENOMEM;
@@ -323,7 +360,7 @@ static int __init local_init(void)
        if (!_rq_tio_cache)
                goto out_free_io_cache;
 
-       _rq_cache = kmem_cache_create("dm_clone_request", sizeof(struct request),
+       _rq_cache = kmem_cache_create("dm_old_clone_request", sizeof(struct request),
                                      __alignof__(struct request), 0, NULL);
        if (!_rq_cache)
                goto out_free_rq_tio_cache;
@@ -556,16 +593,17 @@ static int dm_blk_getgeo(struct block_device *bdev, struct hd_geometry *geo)
        return dm_get_geometry(md, geo);
 }
 
-static int dm_get_live_table_for_ioctl(struct mapped_device *md,
-               struct dm_target **tgt, struct block_device **bdev,
-               fmode_t *mode, int *srcu_idx)
+static int dm_grab_bdev_for_ioctl(struct mapped_device *md,
+                                 struct block_device **bdev,
+                                 fmode_t *mode)
 {
+       struct dm_target *tgt;
        struct dm_table *map;
-       int r;
+       int srcu_idx, r;
 
 retry:
        r = -ENOTTY;
-       map = dm_get_live_table(md, srcu_idx);
+       map = dm_get_live_table(md, &srcu_idx);
        if (!map || !dm_table_get_size(map))
                goto out;
 
@@ -573,9 +611,8 @@ retry:
        if (dm_table_get_num_targets(map) != 1)
                goto out;
 
-       *tgt = dm_table_get_target(map, 0);
-
-       if (!(*tgt)->type->prepare_ioctl)
+       tgt = dm_table_get_target(map, 0);
+       if (!tgt->type->prepare_ioctl)
                goto out;
 
        if (dm_suspended_md(md)) {
@@ -583,14 +620,16 @@ retry:
                goto out;
        }
 
-       r = (*tgt)->type->prepare_ioctl(*tgt, bdev, mode);
+       r = tgt->type->prepare_ioctl(tgt, bdev, mode);
        if (r < 0)
                goto out;
 
+       bdgrab(*bdev);
+       dm_put_live_table(md, srcu_idx);
        return r;
 
 out:
-       dm_put_live_table(md, *srcu_idx);
+       dm_put_live_table(md, srcu_idx);
        if (r == -ENOTCONN && !fatal_signal_pending(current)) {
                msleep(10);
                goto retry;
@@ -602,11 +641,9 @@ 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_target *tgt;
-       struct block_device *tgt_bdev = NULL;
-       int srcu_idx, r;
+       int r;
 
-       r = dm_get_live_table_for_ioctl(md, &tgt, &tgt_bdev, &mode, &srcu_idx);
+       r = dm_grab_bdev_for_ioctl(md, &bdev, &mode);
        if (r < 0)
                return r;
 
@@ -621,9 +658,9 @@ static int dm_blk_ioctl(struct block_device *bdev, fmode_t mode,
                        goto out;
        }
 
-       r =  __blkdev_driver_ioctl(tgt_bdev, mode, cmd, arg);
+       r =  __blkdev_driver_ioctl(bdev, mode, cmd, arg);
 out:
-       dm_put_live_table(md, srcu_idx);
+       bdput(bdev);
        return r;
 }
 
@@ -642,24 +679,24 @@ static void free_tio(struct mapped_device *md, struct dm_target_io *tio)
        bio_put(&tio->clone);
 }
 
-static struct dm_rq_target_io *alloc_rq_tio(struct mapped_device *md,
-                                           gfp_t gfp_mask)
+static struct dm_rq_target_io *alloc_old_rq_tio(struct mapped_device *md,
+                                               gfp_t gfp_mask)
 {
        return mempool_alloc(md->io_pool, gfp_mask);
 }
 
-static void free_rq_tio(struct dm_rq_target_io *tio)
+static void free_old_rq_tio(struct dm_rq_target_io *tio)
 {
        mempool_free(tio, tio->md->io_pool);
 }
 
-static struct request *alloc_clone_request(struct mapped_device *md,
-                                          gfp_t gfp_mask)
+static struct request *alloc_old_clone_request(struct mapped_device *md,
+                                              gfp_t gfp_mask)
 {
        return mempool_alloc(md->rq_pool, gfp_mask);
 }
 
-static void free_clone_request(struct mapped_device *md, struct request *rq)
+static void free_old_clone_request(struct mapped_device *md, struct request *rq)
 {
        mempool_free(rq, md->rq_pool);
 }
@@ -827,7 +864,7 @@ int dm_get_table_device(struct mapped_device *md, dev_t dev, fmode_t mode,
        mutex_lock(&md->table_devices_lock);
        td = find_table_device(&md->table_devices, dev, mode);
        if (!td) {
-               td = kmalloc(sizeof(*td), GFP_KERNEL);
+               td = kmalloc_node(sizeof(*td), GFP_KERNEL, md->numa_node_id);
                if (!td) {
                        mutex_unlock(&md->table_devices_lock);
                        return -ENOMEM;
@@ -1109,12 +1146,8 @@ static void rq_completed(struct mapped_device *md, int rw, bool run_queue)
         * back into ->request_fn() could deadlock attempting to grab the
         * queue lock again.
         */
-       if (run_queue) {
-               if (md->queue->mq_ops)
-                       blk_mq_run_hw_queues(md->queue, true);
-               else
-                       blk_run_queue_async(md->queue);
-       }
+       if (!md->queue->mq_ops && run_queue)
+               blk_run_queue_async(md->queue);
 
        /*
         * dm_put() must be at the end of this function. See the comment above
@@ -1134,15 +1167,10 @@ static void free_rq_clone(struct request *clone)
                tio->ti->type->release_clone_rq(clone);
        else if (!md->queue->mq_ops)
                /* request_fn queue stacked on request_fn queue(s) */
-               free_clone_request(md, clone);
-       /*
-        * NOTE: for the blk-mq queue stacked on request_fn queue(s) case:
-        * no need to call free_clone_request() because we leverage blk-mq by
-        * allocating the clone at the end of the blk-mq pdu (see: clone_rq)
-        */
+               free_old_clone_request(md, clone);
 
        if (!md->queue->mq_ops)
-               free_rq_tio(tio);
+               free_old_rq_tio(tio);
 }
 
 /*
@@ -1191,12 +1219,14 @@ static void dm_unprep_request(struct request *rq)
 
        if (clone)
                free_rq_clone(clone);
+       else if (!tio->md->queue->mq_ops)
+               free_old_rq_tio(tio);
 }
 
 /*
  * Requeue the original request of a clone.
  */
-static void old_requeue_request(struct request *rq)
+static void dm_old_requeue_request(struct request *rq)
 {
        struct request_queue *q = rq->q;
        unsigned long flags;
@@ -1207,6 +1237,18 @@ static void old_requeue_request(struct request *rq)
        spin_unlock_irqrestore(q->queue_lock, flags);
 }
 
+static void dm_mq_requeue_request(struct request *rq)
+{
+       struct request_queue *q = rq->q;
+       unsigned long flags;
+
+       blk_mq_requeue_request(rq);
+       spin_lock_irqsave(q->queue_lock, flags);
+       if (!blk_queue_stopped(q))
+               blk_mq_kick_requeue_list(q);
+       spin_unlock_irqrestore(q->queue_lock, flags);
+}
+
 static void dm_requeue_original_request(struct mapped_device *md,
                                        struct request *rq)
 {
@@ -1216,36 +1258,36 @@ static void dm_requeue_original_request(struct mapped_device *md,
 
        rq_end_stats(md, rq);
        if (!rq->q->mq_ops)
-               old_requeue_request(rq);
-       else {
-               blk_mq_requeue_request(rq);
-               blk_mq_kick_requeue_list(rq->q);
-       }
+               dm_old_requeue_request(rq);
+       else
+               dm_mq_requeue_request(rq);
 
        rq_completed(md, rw, false);
 }
 
-static void old_stop_queue(struct request_queue *q)
+static void dm_old_stop_queue(struct request_queue *q)
 {
        unsigned long flags;
 
-       if (blk_queue_stopped(q))
+       spin_lock_irqsave(q->queue_lock, flags);
+       if (blk_queue_stopped(q)) {
+               spin_unlock_irqrestore(q->queue_lock, flags);
                return;
+       }
 
-       spin_lock_irqsave(q->queue_lock, flags);
        blk_stop_queue(q);
        spin_unlock_irqrestore(q->queue_lock, flags);
 }
 
-static void stop_queue(struct request_queue *q)
+static void dm_stop_queue(struct request_queue *q)
 {
        if (!q->mq_ops)
-               old_stop_queue(q);
+               dm_old_stop_queue(q);
        else
                blk_mq_stop_hw_queues(q);
 }
 
-static void old_start_queue(struct request_queue *q)
+static void dm_old_start_queue(struct request_queue *q)
 {
        unsigned long flags;
 
@@ -1255,12 +1297,14 @@ static void old_start_queue(struct request_queue *q)
        spin_unlock_irqrestore(q->queue_lock, flags);
 }
 
-static void start_queue(struct request_queue *q)
+static void dm_start_queue(struct request_queue *q)
 {
        if (!q->mq_ops)
-               old_start_queue(q);
-       else
+               dm_old_start_queue(q);
+       else {
                blk_mq_start_stopped_hw_queues(q, true);
+               blk_mq_kick_requeue_list(q);
+       }
 }
 
 static void dm_done(struct request *clone, int error, bool mapped)
@@ -1311,7 +1355,7 @@ static void dm_softirq_done(struct request *rq)
                if (!rq->q->mq_ops) {
                        blk_end_request_all(rq, tio->error);
                        rq_completed(tio->md, rw, false);
-                       free_rq_tio(tio);
+                       free_old_rq_tio(tio);
                } else {
                        blk_mq_end_request(rq, tio->error);
                        rq_completed(tio->md, rw, false);
@@ -1334,7 +1378,10 @@ static void dm_complete_request(struct request *rq, int error)
        struct dm_rq_target_io *tio = tio_from_request(rq);
 
        tio->error = error;
-       blk_complete_request(rq);
+       if (!rq->q->mq_ops)
+               blk_complete_request(rq);
+       else
+               blk_mq_complete_request(rq, error);
 }
 
 /*
@@ -1350,7 +1397,7 @@ static void dm_kill_unmapped_request(struct request *rq, int error)
 }
 
 /*
- * Called with the clone's queue lock held (for non-blk-mq)
+ * Called with the clone's queue lock held (in the case of .request_fn)
  */
 static void end_clone_request(struct request *clone, int error)
 {
@@ -1520,21 +1567,26 @@ static void bio_setup_sector(struct bio *bio, sector_t sector, unsigned len)
 /*
  * Creates a bio that consists of range of complete bvecs.
  */
-static void clone_bio(struct dm_target_io *tio, struct bio *bio,
-                     sector_t sector, unsigned len)
+static int clone_bio(struct dm_target_io *tio, struct bio *bio,
+                    sector_t sector, unsigned len)
 {
        struct bio *clone = &tio->clone;
 
        __bio_clone_fast(clone, bio);
 
-       if (bio_integrity(bio))
-               bio_integrity_clone(clone, bio, GFP_NOIO);
+       if (bio_integrity(bio)) {
+               int r = bio_integrity_clone(clone, bio, GFP_NOIO);
+               if (r < 0)
+                       return r;
+       }
 
        bio_advance(clone, to_bytes(sector - clone->bi_iter.bi_sector));
        clone->bi_iter.bi_size = to_bytes(len);
 
        if (bio_integrity(bio))
                bio_integrity_trim(clone, 0, len);
+
+       return 0;
 }
 
 static struct dm_target_io *alloc_tio(struct clone_info *ci,
@@ -1591,13 +1643,14 @@ static int __send_empty_flush(struct clone_info *ci)
        return 0;
 }
 
-static void __clone_and_map_data_bio(struct clone_info *ci, struct dm_target *ti,
+static int __clone_and_map_data_bio(struct clone_info *ci, struct dm_target *ti,
                                     sector_t sector, unsigned *len)
 {
        struct bio *bio = ci->bio;
        struct dm_target_io *tio;
        unsigned target_bio_nr;
        unsigned num_target_bios = 1;
+       int r = 0;
 
        /*
         * Does the target want to receive duplicate copies of the bio?
@@ -1608,9 +1661,13 @@ static void __clone_and_map_data_bio(struct clone_info *ci, struct dm_target *ti
        for (target_bio_nr = 0; target_bio_nr < num_target_bios; target_bio_nr++) {
                tio = alloc_tio(ci, ti, target_bio_nr);
                tio->len_ptr = len;
-               clone_bio(tio, bio, sector, *len);
+               r = clone_bio(tio, bio, sector, *len);
+               if (r < 0)
+                       break;
                __map_bio(tio);
        }
+
+       return r;
 }
 
 typedef unsigned (*get_num_bios_fn)(struct dm_target *ti);
@@ -1687,6 +1744,7 @@ static int __split_and_process_non_flush(struct clone_info *ci)
        struct bio *bio = ci->bio;
        struct dm_target *ti;
        unsigned len;
+       int r;
 
        if (unlikely(bio->bi_rw & REQ_DISCARD))
                return __send_discard(ci);
@@ -1699,7 +1757,9 @@ static int __split_and_process_non_flush(struct clone_info *ci)
 
        len = min_t(sector_t, max_io_len(ci->sector, ti), ci->sector_count);
 
-       __clone_and_map_data_bio(ci, ti, ci->sector, &len);
+       r = __clone_and_map_data_bio(ci, ti, ci->sector, &len);
+       if (r < 0)
+               return r;
 
        ci->sector += len;
        ci->sector_count -= len;
@@ -1837,28 +1897,22 @@ static int setup_clone(struct request *clone, struct request *rq,
        return 0;
 }
 
-static struct request *clone_rq(struct request *rq, struct mapped_device *md,
-                               struct dm_rq_target_io *tio, gfp_t gfp_mask)
+static struct request *clone_old_rq(struct request *rq, struct mapped_device *md,
+                                   struct dm_rq_target_io *tio, gfp_t gfp_mask)
 {
        /*
-        * Do not allocate a clone if tio->clone was already set
-        * (see: dm_mq_queue_rq).
+        * Create clone for use with .request_fn request_queue
         */
-       bool alloc_clone = !tio->clone;
        struct request *clone;
 
-       if (alloc_clone) {
-               clone = alloc_clone_request(md, gfp_mask);
-               if (!clone)
-                       return NULL;
-       } else
-               clone = tio->clone;
+       clone = alloc_old_clone_request(md, gfp_mask);
+       if (!clone)
+               return NULL;
 
        blk_rq_init(NULL, clone);
        if (setup_clone(clone, rq, tio, gfp_mask)) {
                /* -ENOMEM */
-               if (alloc_clone)
-                       free_clone_request(md, clone);
+               free_old_clone_request(md, clone);
                return NULL;
        }
 
@@ -1875,29 +1929,40 @@ static void init_tio(struct dm_rq_target_io *tio, struct request *rq,
        tio->clone = NULL;
        tio->orig = rq;
        tio->error = 0;
-       memset(&tio->info, 0, sizeof(tio->info));
+       /*
+        * Avoid initializing info for blk-mq; it passes
+        * target-specific data through info.ptr
+        * (see: dm_mq_init_request)
+        */
+       if (!md->init_tio_pdu)
+               memset(&tio->info, 0, sizeof(tio->info));
        if (md->kworker_task)
                init_kthread_work(&tio->work, map_tio_request);
 }
 
-static struct dm_rq_target_io *prep_tio(struct request *rq,
-                                       struct mapped_device *md, gfp_t gfp_mask)
+static struct dm_rq_target_io *dm_old_prep_tio(struct request *rq,
+                                              struct mapped_device *md,
+                                              gfp_t gfp_mask)
 {
        struct dm_rq_target_io *tio;
        int srcu_idx;
        struct dm_table *table;
 
-       tio = alloc_rq_tio(md, gfp_mask);
+       tio = alloc_old_rq_tio(md, gfp_mask);
        if (!tio)
                return NULL;
 
        init_tio(tio, rq, md);
 
        table = dm_get_live_table(md, &srcu_idx);
+       /*
+        * Must clone a request if this .request_fn DM device
+        * is stacked on .request_fn device(s).
+        */
        if (!dm_table_mq_request_based(table)) {
-               if (!clone_rq(rq, md, tio, gfp_mask)) {
+               if (!clone_old_rq(rq, md, tio, gfp_mask)) {
                        dm_put_live_table(md, srcu_idx);
-                       free_rq_tio(tio);
+                       free_old_rq_tio(tio);
                        return NULL;
                }
        }
@@ -1909,7 +1974,7 @@ static struct dm_rq_target_io *prep_tio(struct request *rq,
 /*
  * Called with the queue lock held.
  */
-static int dm_prep_fn(struct request_queue *q, struct request *rq)
+static int dm_old_prep_fn(struct request_queue *q, struct request *rq)
 {
        struct mapped_device *md = q->queuedata;
        struct dm_rq_target_io *tio;
@@ -1919,7 +1984,7 @@ static int dm_prep_fn(struct request_queue *q, struct request *rq)
                return BLKPREP_KILL;
        }
 
-       tio = prep_tio(rq, md, GFP_ATOMIC);
+       tio = dm_old_prep_tio(rq, md, GFP_ATOMIC);
        if (!tio)
                return BLKPREP_DEFER;
 
@@ -2077,12 +2142,18 @@ static bool dm_request_peeked_before_merge_deadline(struct mapped_device *md)
 static void dm_request_fn(struct request_queue *q)
 {
        struct mapped_device *md = q->queuedata;
-       int srcu_idx;
-       struct dm_table *map = dm_get_live_table(md, &srcu_idx);
-       struct dm_target *ti;
+       struct dm_target *ti = md->immutable_target;
        struct request *rq;
        struct dm_rq_target_io *tio;
-       sector_t pos;
+       sector_t pos = 0;
+
+       if (unlikely(!ti)) {
+               int srcu_idx;
+               struct dm_table *map = dm_get_live_table(md, &srcu_idx);
+
+               ti = dm_table_find_target(map, pos);
+               dm_put_live_table(md, srcu_idx);
+       }
 
        /*
         * For suspend, check blk_queue_stopped() and increment
@@ -2093,33 +2164,21 @@ static void dm_request_fn(struct request_queue *q)
        while (!blk_queue_stopped(q)) {
                rq = blk_peek_request(q);
                if (!rq)
-                       goto out;
+                       return;
 
                /* 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 rq_completed() requires,
-                        * before calling dm_kill_unmapped_request
-                        */
-                       DMERR_LIMIT("request attempted access beyond the end of device");
-                       dm_start_request(md, rq);
-                       dm_kill_unmapped_request(rq, -EIO);
-                       continue;
+               if ((dm_request_peeked_before_merge_deadline(md) &&
+                    md_in_flight(md) && rq->bio && rq->bio->bi_vcnt == 1 &&
+                    md->last_rq_pos == pos && md->last_rq_rw == rq_data_dir(rq)) ||
+                   (ti->type->busy && ti->type->busy(ti))) {
+                       blk_delay_queue(q, HZ / 100);
+                       return;
                }
 
-               if (dm_request_peeked_before_merge_deadline(md) &&
-                   md_in_flight(md) && rq->bio && rq->bio->bi_vcnt == 1 &&
-                   md->last_rq_pos == pos && md->last_rq_rw == rq_data_dir(rq))
-                       goto delay_and_out;
-
-               if (ti->type->busy && ti->type->busy(ti))
-                       goto delay_and_out;
-
                dm_start_request(md, rq);
 
                tio = tio_from_request(rq);
@@ -2128,13 +2187,6 @@ static void dm_request_fn(struct request_queue *q)
                queue_kthread_work(&md->kworker, &tio->work);
                BUG_ON(!irqs_disabled());
        }
-
-       goto out;
-
-delay_and_out:
-       blk_delay_queue(q, HZ / 100);
-out:
-       dm_put_live_table(md, srcu_idx);
 }
 
 static int dm_any_congested(void *congested_data, int bdi_bits)
@@ -2144,19 +2196,18 @@ static int dm_any_congested(void *congested_data, int bdi_bits)
        struct dm_table *map;
 
        if (!test_bit(DMF_BLOCK_IO_FOR_SUSPEND, &md->flags)) {
-               map = dm_get_live_table_fast(md);
-               if (map) {
+               if (dm_request_based(md)) {
                        /*
-                        * Request-based dm cares about only own queue for
-                        * the query about congestion status of request_queue
+                        * With request-based DM we only need to check the
+                        * top-level queue for congestion.
                         */
-                       if (dm_request_based(md))
-                               r = md->queue->backing_dev_info.wb.state &
-                                   bdi_bits;
-                       else
+                       r = md->queue->backing_dev_info.wb.state & bdi_bits;
+               } else {
+                       map = dm_get_live_table_fast(md);
+                       if (map)
                                r = dm_table_any_congested(map, bdi_bits);
+                       dm_put_live_table_fast(md);
                }
-               dm_put_live_table_fast(md);
        }
 
        return r;
@@ -2236,7 +2287,7 @@ static void dm_init_md_queue(struct mapped_device *md)
        md->queue->backing_dev_info.congested_data = md;
 }
 
-static void dm_init_old_md_queue(struct mapped_device *md)
+static void dm_init_normal_md_queue(struct mapped_device *md)
 {
        md->use_blk_mq = false;
        dm_init_md_queue(md);
@@ -2283,10 +2334,11 @@ static void cleanup_mapped_device(struct mapped_device *md)
  */
 static struct mapped_device *alloc_dev(int minor)
 {
-       int r;
-       struct mapped_device *md = kzalloc(sizeof(*md), GFP_KERNEL);
+       int r, numa_node_id = dm_get_numa_node();
+       struct mapped_device *md;
        void *old_md;
 
+       md = kzalloc_node(sizeof(*md), GFP_KERNEL, numa_node_id);
        if (!md) {
                DMWARN("unable to allocate device, out of memory.");
                return NULL;
@@ -2307,7 +2359,9 @@ static struct mapped_device *alloc_dev(int minor)
        if (r < 0)
                goto bad_io_barrier;
 
+       md->numa_node_id = numa_node_id;
        md->use_blk_mq = use_blk_mq;
+       md->init_tio_pdu = false;
        md->type = DM_TYPE_NONE;
        mutex_init(&md->suspend_lock);
        mutex_init(&md->type_lock);
@@ -2321,13 +2375,13 @@ static struct mapped_device *alloc_dev(int minor)
        INIT_LIST_HEAD(&md->table_devices);
        spin_lock_init(&md->uevent_lock);
 
-       md->queue = blk_alloc_queue(GFP_KERNEL);
+       md->queue = blk_alloc_queue_node(GFP_KERNEL, numa_node_id);
        if (!md->queue)
                goto bad;
 
        dm_init_md_queue(md);
 
-       md->disk = alloc_disk(1);
+       md->disk = alloc_disk_node(1, numa_node_id);
        if (!md->disk)
                goto bad;
 
@@ -2391,8 +2445,10 @@ static void free_dev(struct mapped_device *md)
        unlock_fs(md);
 
        cleanup_mapped_device(md);
-       if (md->use_blk_mq)
-               blk_mq_free_tag_set(&md->tag_set);
+       if (md->tag_set) {
+               blk_mq_free_tag_set(md->tag_set);
+               kfree(md->tag_set);
+       }
 
        free_table_devices(&md->table_devices);
        dm_stats_cleanup(&md->stats);
@@ -2500,13 +2556,20 @@ static struct dm_table *__bind(struct mapped_device *md, struct dm_table *t,
         * 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))
-               stop_queue(q);
+       if (dm_table_request_based(t)) {
+               dm_stop_queue(q);
+               /*
+                * Leverage the fact that request-based DM targets are
+                * immutable singletons and establish md->immutable_target
+                * - used to optimize both dm_request_fn and dm_mq_queue_rq
+                */
+               md->immutable_target = dm_table_get_immutable_target(t);
+       }
 
        __bind_mempools(md, t);
 
        old_map = rcu_dereference_protected(md->map, lockdep_is_held(&md->suspend_lock));
-       rcu_assign_pointer(md->map, t);
+       rcu_assign_pointer(md->map, (void *)t);
        md->immutable_target_type = dm_table_get_immutable_target_type(t);
 
        dm_table_set_restrictions(t, q, limits);
@@ -2572,7 +2635,6 @@ void dm_set_md_type(struct mapped_device *md, unsigned type)
 
 unsigned dm_get_md_type(struct mapped_device *md)
 {
-       BUG_ON(!mutex_is_locked(&md->type_lock));
        return md->type;
 }
 
@@ -2592,7 +2654,7 @@ struct queue_limits *dm_get_queue_limits(struct mapped_device *md)
 }
 EXPORT_SYMBOL_GPL(dm_get_queue_limits);
 
-static void init_rq_based_worker_thread(struct mapped_device *md)
+static void dm_old_init_rq_based_worker_thread(struct mapped_device *md)
 {
        /* Initialize the request-based DM worker thread */
        init_kthread_worker(&md->kworker);
@@ -2601,26 +2663,22 @@ static void init_rq_based_worker_thread(struct mapped_device *md)
 }
 
 /*
- * Fully initialize a request-based queue (->elevator, ->request_fn, etc).
+ * Fully initialize a .request_fn request-based queue.
  */
-static int dm_init_request_based_queue(struct mapped_device *md)
+static int dm_old_init_request_queue(struct mapped_device *md)
 {
-       struct request_queue *q = NULL;
-
        /* Fully initialize the queue */
-       q = blk_init_allocated_queue(md->queue, dm_request_fn, NULL);
-       if (!q)
+       if (!blk_init_allocated_queue(md->queue, dm_request_fn, NULL))
                return -EINVAL;
 
        /* disable dm_request_fn's merge heuristic by default */
        md->seq_rq_merge_deadline_usecs = 0;
 
-       md->queue = q;
-       dm_init_old_md_queue(md);
+       dm_init_normal_md_queue(md);
        blk_queue_softirq_done(md->queue, dm_softirq_done);
-       blk_queue_prep_rq(md->queue, dm_prep_fn);
+       blk_queue_prep_rq(md->queue, dm_old_prep_fn);
 
-       init_rq_based_worker_thread(md);
+       dm_old_init_rq_based_worker_thread(md);
 
        elv_register_queue(md->queue);
 
@@ -2640,6 +2698,11 @@ static int dm_mq_init_request(void *data, struct request *rq,
         */
        tio->md = md;
 
+       if (md->init_tio_pdu) {
+               /* target-specific per-io data is immediately after the tio */
+               tio->info.ptr = tio + 1;
+       }
+
        return 0;
 }
 
@@ -2649,28 +2712,15 @@ static int dm_mq_queue_rq(struct blk_mq_hw_ctx *hctx,
        struct request *rq = bd->rq;
        struct dm_rq_target_io *tio = blk_mq_rq_to_pdu(rq);
        struct mapped_device *md = tio->md;
-       int srcu_idx;
-       struct dm_table *map = dm_get_live_table(md, &srcu_idx);
-       struct dm_target *ti;
-       sector_t pos;
+       struct dm_target *ti = md->immutable_target;
 
-       /* 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);
+       if (unlikely(!ti)) {
+               int srcu_idx;
+               struct dm_table *map = dm_get_live_table(md, &srcu_idx);
 
-       ti = dm_table_find_target(map, pos);
-       if (!dm_target_is_valid(ti)) {
+               ti = dm_table_find_target(map, 0);
                dm_put_live_table(md, srcu_idx);
-               DMERR_LIMIT("request attempted access beyond the end of device");
-               /*
-                * Must perform setup, that rq_completed() requires,
-                * before returning BLK_MQ_RQ_QUEUE_ERROR
-                */
-               dm_start_request(md, rq);
-               return BLK_MQ_RQ_QUEUE_ERROR;
        }
-       dm_put_live_table(md, srcu_idx);
 
        if (ti->type->busy && ti->type->busy(ti))
                return BLK_MQ_RQ_QUEUE_BUSY;
@@ -2686,20 +2736,12 @@ static int dm_mq_queue_rq(struct blk_mq_hw_ctx *hctx,
         */
        tio->ti = ti;
 
-       /* Clone the request if underlying devices aren't blk-mq */
-       if (dm_table_get_type(map) == DM_TYPE_REQUEST_BASED) {
-               /* clone request is allocated at the end of the pdu */
-               tio->clone = (void *)blk_mq_rq_to_pdu(rq) + sizeof(struct dm_rq_target_io);
-               (void) clone_rq(rq, md, tio, GFP_ATOMIC);
-               queue_kthread_work(&md->kworker, &tio->work);
-       } else {
-               /* Direct call is fine since .queue_rq allows allocations */
-               if (map_request(tio, rq, md) == DM_MAPIO_REQUEUE) {
-                       /* Undo dm_start_request() before requeuing */
-                       rq_end_stats(md, rq);
-                       rq_completed(md, rq_data_dir(rq), false);
-                       return BLK_MQ_RQ_QUEUE_BUSY;
-               }
+       /* Direct call is fine since .queue_rq allows allocations */
+       if (map_request(tio, rq, md) == DM_MAPIO_REQUEUE) {
+               /* Undo dm_start_request() before requeuing */
+               rq_end_stats(md, rq);
+               rq_completed(md, rq_data_dir(rq), false);
+               return BLK_MQ_RQ_QUEUE_BUSY;
        }
 
        return BLK_MQ_RQ_QUEUE_OK;
@@ -2712,47 +2754,56 @@ static struct blk_mq_ops dm_mq_ops = {
        .init_request = dm_mq_init_request,
 };
 
-static int dm_init_request_based_blk_mq_queue(struct mapped_device *md)
+static int dm_mq_init_request_queue(struct mapped_device *md,
+                                   struct dm_target *immutable_tgt)
 {
-       unsigned md_type = dm_get_md_type(md);
        struct request_queue *q;
        int err;
 
-       memset(&md->tag_set, 0, sizeof(md->tag_set));
-       md->tag_set.ops = &dm_mq_ops;
-       md->tag_set.queue_depth = BLKDEV_MAX_RQ;
-       md->tag_set.numa_node = NUMA_NO_NODE;
-       md->tag_set.flags = BLK_MQ_F_SHOULD_MERGE | BLK_MQ_F_SG_MERGE;
-       md->tag_set.nr_hw_queues = 1;
-       if (md_type == DM_TYPE_REQUEST_BASED) {
-               /* make the memory for non-blk-mq clone part of the pdu */
-               md->tag_set.cmd_size = sizeof(struct dm_rq_target_io) + sizeof(struct request);
-       } else
-               md->tag_set.cmd_size = sizeof(struct dm_rq_target_io);
-       md->tag_set.driver_data = md;
-
-       err = blk_mq_alloc_tag_set(&md->tag_set);
+       if (dm_get_md_type(md) == DM_TYPE_REQUEST_BASED) {
+               DMERR("request-based dm-mq may only be stacked on blk-mq device(s)");
+               return -EINVAL;
+       }
+
+       md->tag_set = kzalloc_node(sizeof(struct blk_mq_tag_set), GFP_KERNEL, md->numa_node_id);
+       if (!md->tag_set)
+               return -ENOMEM;
+
+       md->tag_set->ops = &dm_mq_ops;
+       md->tag_set->queue_depth = dm_get_blk_mq_queue_depth();
+       md->tag_set->numa_node = md->numa_node_id;
+       md->tag_set->flags = BLK_MQ_F_SHOULD_MERGE | BLK_MQ_F_SG_MERGE;
+       md->tag_set->nr_hw_queues = dm_get_blk_mq_nr_hw_queues();
+       md->tag_set->driver_data = md;
+
+       md->tag_set->cmd_size = sizeof(struct dm_rq_target_io);
+       if (immutable_tgt && immutable_tgt->per_io_data_size) {
+               /* any target-specific per-io data is immediately after the tio */
+               md->tag_set->cmd_size += immutable_tgt->per_io_data_size;
+               md->init_tio_pdu = true;
+       }
+
+       err = blk_mq_alloc_tag_set(md->tag_set);
        if (err)
-               return err;
+               goto out_kfree_tag_set;
 
-       q = blk_mq_init_allocated_queue(&md->tag_set, md->queue);
+       q = blk_mq_init_allocated_queue(md->tag_set, md->queue);
        if (IS_ERR(q)) {
                err = PTR_ERR(q);
                goto out_tag_set;
        }
-       md->queue = q;
        dm_init_md_queue(md);
 
        /* backfill 'mq' sysfs registration normally done in blk_register_queue */
        blk_mq_register_disk(md->disk);
 
-       if (md_type == DM_TYPE_REQUEST_BASED)
-               init_rq_based_worker_thread(md);
-
        return 0;
 
 out_tag_set:
-       blk_mq_free_tag_set(&md->tag_set);
+       blk_mq_free_tag_set(md->tag_set);
+out_kfree_tag_set:
+       kfree(md->tag_set);
+
        return err;
 }
 
@@ -2767,28 +2818,28 @@ static unsigned filter_md_type(unsigned type, struct mapped_device *md)
 /*
  * Setup the DM device's queue based on md's type
  */
-int dm_setup_md_queue(struct mapped_device *md)
+int dm_setup_md_queue(struct mapped_device *md, struct dm_table *t)
 {
        int r;
        unsigned md_type = filter_md_type(dm_get_md_type(md), md);
 
        switch (md_type) {
        case DM_TYPE_REQUEST_BASED:
-               r = dm_init_request_based_queue(md);
+               r = dm_old_init_request_queue(md);
                if (r) {
-                       DMWARN("Cannot initialize queue for request-based mapped device");
+                       DMERR("Cannot initialize queue for request-based mapped device");
                        return r;
                }
                break;
        case DM_TYPE_MQ_REQUEST_BASED:
-               r = dm_init_request_based_blk_mq_queue(md);
+               r = dm_mq_init_request_queue(md, dm_table_get_immutable_target(t));
                if (r) {
-                       DMWARN("Cannot initialize queue for request-based blk-mq mapped device");
+                       DMERR("Cannot initialize queue for request-based dm-mq mapped device");
                        return r;
                }
                break;
        case DM_TYPE_BIO_BASED:
-               dm_init_old_md_queue(md);
+               dm_init_normal_md_queue(md);
                blk_queue_make_request(md->queue, dm_make_request);
                /*
                 * DM handles splitting bios as needed.  Free the bio_split bioset
@@ -3131,7 +3182,7 @@ static int __dm_suspend(struct mapped_device *md, struct dm_table *map,
         * dm defers requests to md->wq from md->queue.
         */
        if (dm_request_based(md)) {
-               stop_queue(md->queue);
+               dm_stop_queue(md->queue);
                if (md->kworker_task)
                        flush_kthread_worker(&md->kworker);
        }
@@ -3155,7 +3206,7 @@ static int __dm_suspend(struct mapped_device *md, struct dm_table *map,
                dm_queue_flush(md);
 
                if (dm_request_based(md))
-                       start_queue(md->queue);
+                       dm_start_queue(md->queue);
 
                unlock_fs(md);
                dm_table_presuspend_undo_targets(map);
@@ -3234,7 +3285,7 @@ static int __dm_resume(struct mapped_device *md, struct dm_table *map)
         * Request-based dm is queueing the deferred I/Os in its request_queue.
         */
        if (dm_request_based(md))
-               start_queue(md->queue);
+               dm_start_queue(md->queue);
 
        unlock_fs(md);
 
@@ -3480,9 +3531,9 @@ int dm_noflush_suspending(struct dm_target *ti)
 EXPORT_SYMBOL_GPL(dm_noflush_suspending);
 
 struct dm_md_mempools *dm_alloc_md_mempools(struct mapped_device *md, unsigned type,
-                                           unsigned integrity, unsigned per_bio_data_size)
+                                           unsigned integrity, unsigned per_io_data_size)
 {
-       struct dm_md_mempools *pools = kzalloc(sizeof(*pools), GFP_KERNEL);
+       struct dm_md_mempools *pools = kzalloc_node(sizeof(*pools), GFP_KERNEL, md->numa_node_id);
        struct kmem_cache *cachep = NULL;
        unsigned int pool_size = 0;
        unsigned int front_pad;
@@ -3496,7 +3547,7 @@ struct dm_md_mempools *dm_alloc_md_mempools(struct mapped_device *md, unsigned t
        case DM_TYPE_BIO_BASED:
                cachep = _io_cache;
                pool_size = dm_get_reserved_bio_based_ios();
-               front_pad = roundup(per_bio_data_size, __alignof__(struct dm_target_io)) + offsetof(struct dm_target_io, clone);
+               front_pad = roundup(per_io_data_size, __alignof__(struct dm_target_io)) + offsetof(struct dm_target_io, clone);
                break;
        case DM_TYPE_REQUEST_BASED:
                cachep = _rq_tio_cache;
@@ -3509,8 +3560,7 @@ struct dm_md_mempools *dm_alloc_md_mempools(struct mapped_device *md, unsigned t
                if (!pool_size)
                        pool_size = dm_get_reserved_rq_based_ios();
                front_pad = offsetof(struct dm_rq_clone_bio_info, clone);
-               /* per_bio_data_size is not used. See __bind_mempools(). */
-               WARN_ON(per_bio_data_size != 0);
+               /* per_io_data_size is used for blk-mq pdu at queue allocation */
                break;
        default:
                BUG();
@@ -3552,15 +3602,14 @@ void dm_free_md_mempools(struct dm_md_mempools *pools)
 }
 
 static int dm_pr_register(struct block_device *bdev, u64 old_key, u64 new_key,
-               u32 flags)
+                         u32 flags)
 {
        struct mapped_device *md = bdev->bd_disk->private_data;
        const struct pr_ops *ops;
-       struct dm_target *tgt;
        fmode_t mode;
-       int srcu_idx, r;
+       int r;
 
-       r = dm_get_live_table_for_ioctl(md, &tgt, &bdev, &mode, &srcu_idx);
+       r = dm_grab_bdev_for_ioctl(md, &bdev, &mode);
        if (r < 0)
                return r;
 
@@ -3570,20 +3619,19 @@ static int dm_pr_register(struct block_device *bdev, u64 old_key, u64 new_key,
        else
                r = -EOPNOTSUPP;
 
-       dm_put_live_table(md, srcu_idx);
+       bdput(bdev);
        return r;
 }
 
 static int dm_pr_reserve(struct block_device *bdev, u64 key, enum pr_type type,
-               u32 flags)
+                        u32 flags)
 {
        struct mapped_device *md = bdev->bd_disk->private_data;
        const struct pr_ops *ops;
-       struct dm_target *tgt;
        fmode_t mode;
-       int srcu_idx, r;
+       int r;
 
-       r = dm_get_live_table_for_ioctl(md, &tgt, &bdev, &mode, &srcu_idx);
+       r = dm_grab_bdev_for_ioctl(md, &bdev, &mode);
        if (r < 0)
                return r;
 
@@ -3593,7 +3641,7 @@ static int dm_pr_reserve(struct block_device *bdev, u64 key, enum pr_type type,
        else
                r = -EOPNOTSUPP;
 
-       dm_put_live_table(md, srcu_idx);
+       bdput(bdev);
        return r;
 }
 
@@ -3601,11 +3649,10 @@ static int dm_pr_release(struct block_device *bdev, u64 key, enum pr_type type)
 {
        struct mapped_device *md = bdev->bd_disk->private_data;
        const struct pr_ops *ops;
-       struct dm_target *tgt;
        fmode_t mode;
-       int srcu_idx, r;
+       int r;
 
-       r = dm_get_live_table_for_ioctl(md, &tgt, &bdev, &mode, &srcu_idx);
+       r = dm_grab_bdev_for_ioctl(md, &bdev, &mode);
        if (r < 0)
                return r;
 
@@ -3615,20 +3662,19 @@ static int dm_pr_release(struct block_device *bdev, u64 key, enum pr_type type)
        else
                r = -EOPNOTSUPP;
 
-       dm_put_live_table(md, srcu_idx);
+       bdput(bdev);
        return r;
 }
 
 static int dm_pr_preempt(struct block_device *bdev, u64 old_key, u64 new_key,
-               enum pr_type type, bool abort)
+                        enum pr_type type, bool abort)
 {
        struct mapped_device *md = bdev->bd_disk->private_data;
        const struct pr_ops *ops;
-       struct dm_target *tgt;
        fmode_t mode;
-       int srcu_idx, r;
+       int r;
 
-       r = dm_get_live_table_for_ioctl(md, &tgt, &bdev, &mode, &srcu_idx);
+       r = dm_grab_bdev_for_ioctl(md, &bdev, &mode);
        if (r < 0)
                return r;
 
@@ -3638,7 +3684,7 @@ static int dm_pr_preempt(struct block_device *bdev, u64 old_key, u64 new_key,
        else
                r = -EOPNOTSUPP;
 
-       dm_put_live_table(md, srcu_idx);
+       bdput(bdev);
        return r;
 }
 
@@ -3646,11 +3692,10 @@ static int dm_pr_clear(struct block_device *bdev, u64 key)
 {
        struct mapped_device *md = bdev->bd_disk->private_data;
        const struct pr_ops *ops;
-       struct dm_target *tgt;
        fmode_t mode;
-       int srcu_idx, r;
+       int r;
 
-       r = dm_get_live_table_for_ioctl(md, &tgt, &bdev, &mode, &srcu_idx);
+       r = dm_grab_bdev_for_ioctl(md, &bdev, &mode);
        if (r < 0)
                return r;
 
@@ -3660,7 +3705,7 @@ static int dm_pr_clear(struct block_device *bdev, u64 key)
        else
                r = -EOPNOTSUPP;
 
-       dm_put_live_table(md, srcu_idx);
+       bdput(bdev);
        return r;
 }
 
@@ -3699,6 +3744,15 @@ MODULE_PARM_DESC(reserved_rq_based_ios, "Reserved IOs in request-based mempools"
 module_param(use_blk_mq, bool, S_IRUGO | S_IWUSR);
 MODULE_PARM_DESC(use_blk_mq, "Use block multiqueue for request-based DM devices");
 
+module_param(dm_mq_nr_hw_queues, uint, S_IRUGO | S_IWUSR);
+MODULE_PARM_DESC(dm_mq_nr_hw_queues, "Number of hardware queues for request-based dm-mq devices");
+
+module_param(dm_mq_queue_depth, uint, S_IRUGO | S_IWUSR);
+MODULE_PARM_DESC(dm_mq_queue_depth, "Queue depth for request-based dm-mq devices");
+
+module_param(dm_numa_node, int, S_IRUGO | S_IWUSR);
+MODULE_PARM_DESC(dm_numa_node, "NUMA node for DM device memory allocations");
+
 MODULE_DESCRIPTION(DM_NAME " driver");
 MODULE_AUTHOR("Joe Thornber <dm-devel@redhat.com>");
 MODULE_LICENSE("GPL");