dm: use rcu_dereference_protected instead of rcu_dereference
authorEric Dumazet <edumazet@google.com>
Sun, 23 Nov 2014 17:34:29 +0000 (09:34 -0800)
committerMike Snitzer <snitzer@redhat.com>
Mon, 24 Nov 2014 01:32:45 +0000 (20:32 -0500)
commita12f5d48bdfeb5fe10157ac01c3de29269f457c6
tree529fb84cea28c6d6a65e6458ff82e520f7353136
parentd200c30ef00dd03aec6f1aeaac1546c6e515cbc0
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>
drivers/md/dm.c