1 files changed, 136 insertions, 26 deletions

diff --git a/drivers/md/dm.c b/drivers/md/dm.c
index be003e5fea3d..5a843c1f4d64 100644
--- a/drivers/md/dm.c
+++ b/drivers/md/dm.c
@@ -190,6 +190,15 @@ struct mapped_device {
         struct bio barrier_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;
@@ -1739,10 +1748,22 @@ static struct mapped_device *alloc_dev(int minor)
         INIT_LIST_HEAD(&md->uevent_list);
         spin_lock_init(&md->uevent_lock);
 
-        md->queue = blk_alloc_queue(GFP_KERNEL);
+        md->queue = blk_init_queue(dm_request_fn, NULL);
         if (!md->queue)
                 goto bad_queue;
 
+        /*
+         * 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,
+         * although we initialized the queue using blk_init_queue().
+         * 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->saved_make_request_fn = md->queue->make_request_fn;
         md->queue->queuedata = md;
         md->queue->backing_dev_info.congested_fn = dm_any_congested;
         md->queue->backing_dev_info.congested_data = md;
@@ -1751,18 +1772,9 @@ static struct mapped_device *alloc_dev(int minor)
         blk_queue_bounce_limit(md->queue, BLK_BOUNCE_ANY);
         md->queue->unplug_fn = dm_unplug_all;
         blk_queue_merge_bvec(md->queue, dm_merge_bvec);
-
-        md->io_pool = mempool_create_slab_pool(MIN_IOS, _io_cache);
-        if (!md->io_pool)
-                goto bad_io_pool;
-
-        md->tio_pool = mempool_create_slab_pool(MIN_IOS, _tio_cache);
-        if (!md->tio_pool)
-                goto bad_tio_pool;
-
-        md->bs = bioset_create(16, 0);
-        if (!md->bs)
-                goto bad_no_bioset;
+        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);
 
         md->disk = alloc_disk(1);
         if (!md->disk)
@@ -1804,12 +1816,6 @@ bad_bdev:
 bad_thread:
         put_disk(md->disk);
 bad_disk:
-        bioset_free(md->bs);
-bad_no_bioset:
-        mempool_destroy(md->tio_pool);
-bad_tio_pool:
-        mempool_destroy(md->io_pool);
-bad_io_pool:
         blk_cleanup_queue(md->queue);
 bad_queue:
         free_minor(minor);
@@ -1829,9 +1835,12 @@ static void free_dev(struct mapped_device *md)
         unlock_fs(md);
         bdput(md->bdev);
         destroy_workqueue(md->wq);
-        mempool_destroy(md->tio_pool);
-        mempool_destroy(md->io_pool);
-        bioset_free(md->bs);
+        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);
@@ -1846,6 +1855,29 @@ static void free_dev(struct mapped_device *md)
         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.
  */
@@ -1897,6 +1929,18 @@ static int __bind(struct mapped_device *md, struct dm_table *t,
 
         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);
+
         write_lock(&md->map_lock);
         md->map = t;
         dm_table_set_restrictions(t, q, limits);
@@ -2110,10 +2154,14 @@ static void dm_wq_work(struct work_struct *work)
 
                 up_write(&md->io_lock);
 
-                if (bio_barrier(c))
-                        process_barrier(md, c);
-                else
-                        __split_and_process_bio(md, c);
+                if (dm_request_based(md))
+                        generic_make_request(c);
+                else {
+                        if (bio_barrier(c))
+                                process_barrier(md, c);
+                        else
+                                __split_and_process_bio(md, c);
+                }
 
                 down_write(&md->io_lock);
         }
@@ -2146,6 +2194,13 @@ int dm_swap_table(struct mapped_device *md, struct dm_table *table)
         if (r)
                 goto out;
 
+        /* cannot change the device type, once a table is bound */
+        if (md->map &&
+            (dm_table_get_type(md->map) != dm_table_get_type(table))) {
+                DMWARN("can't change the device type after a table is bound");
+                goto out;
+        }
+
         __unbind(md);
         r = __bind(md, table, &limits);
 
@@ -2542,6 +2597,61 @@ int dm_noflush_suspending(struct dm_target *ti)
 }
 EXPORT_SYMBOL_GPL(dm_noflush_suspending);
 
+struct dm_md_mempools *dm_alloc_md_mempools(unsigned type)
+{
+        struct dm_md_mempools *pools = kmalloc(sizeof(*pools), GFP_KERNEL);
+
+        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 = (type == DM_TYPE_BIO_BASED) ?
+                    bioset_create(16, 0) : bioset_create(MIN_IOS, 0);
+        if (!pools->bs)
+                goto free_tio_pool_and_out;
+
+        return pools;
+
+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 struct block_device_operations dm_blk_dops = {
         .open = dm_blk_open,
         .release = dm_blk_close,