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| author | Eric Dumazet <edumazet@google.com> | 2014-11-23 09:34:29 -0800 |
|---|---|---|
| committer | Mike Snitzer <snitzer@redhat.com> | 2014-11-23 20:32:45 -0500 |
| commit | a12f5d48bdfeb5fe10157ac01c3de29269f457c6 (patch) | |
| tree | 529fb84cea28c6d6a65e6458ff82e520f7353136 /drivers/md | |
| parent | d200c30ef00dd03aec6f1aeaac1546c6e515cbc0 (diff) | |
| download | talos-op-linux-a12f5d48bdfeb5fe10157ac01c3de29269f457c6.tar.gz talos-op-linux-a12f5d48bdfeb5fe10157ac01c3de29269f457c6.zip | |
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.c | 10 |
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 |
