dm: Use rcu_dereference() for accessing rcu pointer
The map field in 'struct mapped_device' is an rcu pointer. Use rcu_dereference()
while accessing it.
Signed-off-by: Pranith Kumar <bobby.prani@gmail.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
diff --git a/drivers/md/dm.c b/drivers/md/dm.c
index 0fee0e5..c5e14ee 100644
--- a/drivers/md/dm.c
+++ b/drivers/md/dm.c
@@ -2332,7 +2332,7 @@
merge_is_optional = dm_table_merge_is_optional(t);
- old_map = md->map;
+ old_map = rcu_dereference(md->map);
rcu_assign_pointer(md->map, t);
md->immutable_target_type = dm_table_get_immutable_target_type(t);
@@ -2351,7 +2351,7 @@
*/
static struct dm_table *__unbind(struct mapped_device *md)
{
- struct dm_table *map = md->map;
+ struct dm_table *map = rcu_dereference(md->map);
if (!map)
return NULL;
@@ -2745,7 +2745,7 @@
goto out_unlock;
}
- map = md->map;
+ map = rcu_dereference(md->map);
/*
* DMF_NOFLUSH_SUSPENDING must be set before presuspend.
@@ -2839,7 +2839,7 @@
if (!dm_suspended_md(md))
goto out;
- map = md->map;
+ map = rcu_dereference(md->map);
if (!map || !dm_table_get_size(map))
goto out;