Got Paul's email wrong the first time.

The map field in 'struct mapped_device' is an rcu pointer. Use rcu_dereference()
while accessing it.

Signed-off-by: Pranith Kumar <bobby.pr...@gmail.com>
---
 drivers/md/dm.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/drivers/md/dm.c b/drivers/md/dm.c
index 746411b..fbdf0bb 100644
--- a/drivers/md/dm.c
+++ b/drivers/md/dm.c
@@ -2211,7 +2211,7 @@ static struct dm_table *__bind(struct mapped_device *md, 
struct dm_table *t,
 
        merge_is_optional = dm_table_merge_is_optional(t);
 
-       old_map = 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);
 
@@ -2230,7 +2230,7 @@ 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 = md->map;
+       struct dm_table *map = rcu_dereference(md->map);
 
        if (!map)
                return NULL;
@@ -2624,7 +2624,7 @@ int dm_suspend(struct mapped_device *md, unsigned 
suspend_flags)
                goto out_unlock;
        }
 
-       map = md->map;
+       map = rcu_dereference(md->map);
 
        /*
         * DMF_NOFLUSH_SUSPENDING must be set before presuspend.
@@ -2718,7 +2718,7 @@ int dm_resume(struct mapped_device *md)
        if (!dm_suspended_md(md))
                goto out;
 
-       map = md->map;
+       map = rcu_dereference(md->map);
        if (!map || !dm_table_get_size(map))
                goto out;
 
-- 
1.9.1

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