[RESEND PATCH] drivers/md: Use rcu_dereference() for accessing rcu pointer

[Pranith Kumar]

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 <***@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;

[Paul E. McKenney]

Post by Pranith Kumar
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.

OK, I now have all three queued (including the extraneous first line of
the commit log above...), will see what 0day thinks of it.

Thanx, Paul

Post by Pranith Kumar
---
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