dm: fix sparse "unexpected unlock" warnings in ioctl code

Rename dm_get_live_table_for_ioctl to dm_grab_bdev_for_ioctl and have it
do the dm_{get,put}_live_table() rather than split those operations.

The dm_grab_bdev_for_ioctl() callers only care about the block_device
associated with a singleton DM device so there isn't any need to retain
a reference to the live DM table.  It is sufficient to:
1) dm_get_live_table()
2) bdgrab() the bdev associated with the singleton table's target
3) dm_put_live_table()
4) bdput() the bdev

Signed-off-by: Mike Snitzer <snitzer@redhat.com>

1 files changed, 29 insertions, 27 deletions

diff --git a/drivers/md/dm.c b/drivers/md/dm.c
index e9e74e6274d4..a712fd73a55f 100644
--- a/drivers/md/dm.c
+++ b/drivers/md/dm.c
@@ -556,17 +556,17 @@ 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 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;
 
@@ -587,10 +587,12 @@ retry:
         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;
@@ -602,9 +604,9 @@ 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;
-        int srcu_idx, r;
+        int r;
 
-        r = dm_get_live_table_for_ioctl(md, &bdev, &mode, &srcu_idx);
+        r = dm_grab_bdev_for_ioctl(md, &bdev, &mode);
         if (r < 0)
                 return r;
 
@@ -621,7 +623,7 @@ static int dm_blk_ioctl(struct block_device *bdev, fmode_t mode,
 
         r =  __blkdev_driver_ioctl(bdev, mode, cmd, arg);
 out:
-        dm_put_live_table(md, srcu_idx);
+        bdput(bdev);
         return r;
 }
 
@@ -3552,14 +3554,14 @@ 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;
         fmode_t mode;
-        int srcu_idx, r;
+        int r;
 
-        r = dm_get_live_table_for_ioctl(md, &bdev, &mode, &srcu_idx);
+        r = dm_grab_bdev_for_ioctl(md, &bdev, &mode);
         if (r < 0)
                 return r;
 
@@ -3569,19 +3571,19 @@ 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;
         fmode_t mode;
-        int srcu_idx, r;
+        int r;
 
-        r = dm_get_live_table_for_ioctl(md, &bdev, &mode, &srcu_idx);
+        r = dm_grab_bdev_for_ioctl(md, &bdev, &mode);
         if (r < 0)
                 return r;
 
@@ -3591,7 +3593,7 @@ 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;
 }
 
@@ -3600,9 +3602,9 @@ 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;
         fmode_t mode;
-        int srcu_idx, r;
+        int r;
 
-        r = dm_get_live_table_for_ioctl(md, &bdev, &mode, &srcu_idx);
+        r = dm_grab_bdev_for_ioctl(md, &bdev, &mode);
         if (r < 0)
                 return r;
 
@@ -3612,19 +3614,19 @@ 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;
         fmode_t mode;
-        int srcu_idx, r;
+        int r;
 
-        r = dm_get_live_table_for_ioctl(md, &bdev, &mode, &srcu_idx);
+        r = dm_grab_bdev_for_ioctl(md, &bdev, &mode);
         if (r < 0)
                 return r;
 
@@ -3634,7 +3636,7 @@ 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;
 }
 
@@ -3643,9 +3645,9 @@ 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;
         fmode_t mode;
-        int srcu_idx, r;
+        int r;
 
-        r = dm_get_live_table_for_ioctl(md, &bdev, &mode, &srcu_idx);
+        r = dm_grab_bdev_for_ioctl(md, &bdev, &mode);
         if (r < 0)
                 return r;
 
@@ -3655,7 +3657,7 @@ 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;
 }