1 files changed, 13 insertions, 10 deletions

diff --git a/drivers/md/dm.c b/drivers/md/dm.c
index f48a2f359ac4..eaa3af0e0632 100644
--- a/drivers/md/dm.c
+++ b/drivers/md/dm.c
@@ -32,7 +32,6 @@
 #define DM_COOKIE_ENV_VAR_NAME "DM_COOKIE"
 #define DM_COOKIE_LENGTH 24
 
-static DEFINE_MUTEX(dm_mutex);
 static const char *_name = DM_NAME;
 
 static unsigned int major = 0;
@@ -328,7 +327,6 @@ static int dm_blk_open(struct block_device *bdev, fmode_t mode)
 {
         struct mapped_device *md;
 
-        mutex_lock(&dm_mutex);
         spin_lock(&_minor_lock);
 
         md = bdev->bd_disk->private_data;
@@ -346,7 +344,6 @@ static int dm_blk_open(struct block_device *bdev, fmode_t mode)
 
 out:
         spin_unlock(&_minor_lock);
-        mutex_unlock(&dm_mutex);
 
         return md ? 0 : -ENXIO;
 }
@@ -355,10 +352,12 @@ static int dm_blk_close(struct gendisk *disk, fmode_t mode)
 {
         struct mapped_device *md = disk->private_data;
 
-        mutex_lock(&dm_mutex);
+        spin_lock(&_minor_lock);
+
         atomic_dec(&md->open_count);
         dm_put(md);
-        mutex_unlock(&dm_mutex);
+
+        spin_unlock(&_minor_lock);
 
         return 0;
 }
@@ -1638,13 +1637,15 @@ static void dm_request_fn(struct request_queue *q)
                 if (map_request(ti, clone, md))
                         goto requeued;
 
-                spin_lock_irq(q->queue_lock);
+                BUG_ON(!irqs_disabled());
+                spin_lock(q->queue_lock);
         }
 
         goto out;
 
 requeued:
-        spin_lock_irq(q->queue_lock);
+        BUG_ON(!irqs_disabled());
+        spin_lock(q->queue_lock);
 
 plug_and_out:
         if (!elv_queue_empty(q))
@@ -1884,7 +1885,8 @@ static struct mapped_device *alloc_dev(int minor)
         add_disk(md->disk);
         format_dev_t(md->name, MKDEV(_major, minor));
 
-        md->wq = create_singlethread_workqueue("kdmflush");
+        md->wq = alloc_workqueue("kdmflush",
+                                 WQ_NON_REENTRANT | WQ_MEM_RECLAIM, 0);
         if (!md->wq)
                 goto bad_thread;
 
@@ -1992,13 +1994,14 @@ static void event_callback(void *context)
         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);
 
-        mutex_lock(&md->bdev->bd_inode->i_mutex);
         i_size_write(md->bdev->bd_inode, (loff_t)size << SECTOR_SHIFT);
-        mutex_unlock(&md->bdev->bd_inode->i_mutex);
 }
 
 /*