aboutsummaryrefslogtreecommitdiffstats
path: root/drivers/md
diff options
context:
space:
mode:
authorEric Dumazet <edumazet@google.com>2014-11-23 09:34:29 -0800
committerMike Snitzer <snitzer@redhat.com>2014-11-23 20:32:45 -0500
commita12f5d48bdfeb5fe10157ac01c3de29269f457c6 (patch)
tree529fb84cea28c6d6a65e6458ff82e520f7353136 /drivers/md
parentd200c30ef00dd03aec6f1aeaac1546c6e515cbc0 (diff)
dm: use rcu_dereference_protected instead of rcu_dereference
rcu_dereference() should be used in sections protected by rcu_read_lock. For writers, holding some kind of mutex or lock, rcu_dereference_protected() is the way to go, adding explicit lockdep bits. In __unbind(), we are the last user of this mapped device, so can use the constant '1' instead of a lockdep_is_held(), not consistent with other uses of rcu_dereference_protected() which use md->suspend_lock mutex. Reported-by: Kirill A. Shutemov <kirill@shutemov.name> Signed-off-by: Eric Dumazet <edumazet@google.com> Fixes: 33423974bfc1 ("dm: Use rcu_dereference() for accessing rcu pointer") Cc: Pranith Kumar <bobby.prani@gmail.com> [snitzer: allow lines longer than 80 columns, refine subject] Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Diffstat (limited to 'drivers/md')
-rw-r--r--drivers/md/dm.c10
1 files changed, 5 insertions, 5 deletions
diff --git a/drivers/md/dm.c b/drivers/md/dm.c
index a0ece87ad426..8f37ed215b19 100644
--- a/drivers/md/dm.c
+++ b/drivers/md/dm.c
@@ -2335,7 +2335,7 @@ static struct dm_table *__bind(struct mapped_device *md, struct dm_table *t,
merge_is_optional = dm_table_merge_is_optional(t);
- old_map = rcu_dereference(md->map);
+ old_map = rcu_dereference_protected(md->map, lockdep_is_held(&md->suspend_lock));
rcu_assign_pointer(md->map, t);
md->immutable_target_type = dm_table_get_immutable_target_type(t);
@@ -2355,7 +2355,7 @@ static struct dm_table *__bind(struct mapped_device *md, struct dm_table *t,
*/
static struct dm_table *__unbind(struct mapped_device *md)
{
- struct dm_table *map = rcu_dereference(md->map);
+ struct dm_table *map = rcu_dereference_protected(md->map, 1);
if (!map)
return NULL;
@@ -2850,7 +2850,7 @@ retry:
goto retry;
}
- map = rcu_dereference(md->map);
+ map = rcu_dereference_protected(md->map, lockdep_is_held(&md->suspend_lock));
r = __dm_suspend(md, map, suspend_flags, TASK_INTERRUPTIBLE);
if (r)
@@ -2908,7 +2908,7 @@ retry:
goto retry;
}
- map = rcu_dereference(md->map);
+ map = rcu_dereference_protected(md->map, lockdep_is_held(&md->suspend_lock));
if (!map || !dm_table_get_size(map))
goto out;
@@ -2943,7 +2943,7 @@ static void __dm_internal_suspend(struct mapped_device *md, unsigned suspend_fla
return; /* nest suspend */
}
- map = rcu_dereference(md->map);
+ map = rcu_dereference_protected(md->map, lockdep_is_held(&md->suspend_lock));
/*
* Using TASK_UNINTERRUPTIBLE because only NOFLUSH internal suspend is

Privacy Policy