md: avoid taking the mutex on some ioctls.
authorNeilBrown <neilb@suse.de>
Thu, 11 Oct 2012 02:37:33 +0000 (13:37 +1100)
committerNeilBrown <neilb@suse.de>
Thu, 11 Oct 2012 02:37:33 +0000 (13:37 +1100)
commit1ca69c4bc4b1ef889861db39f325901eadbf9497
treea4c83843fc630c42853e1a5ecc51dff5ab3ef54f
parent4ed8731d8e6bd2a88a30697fbf4f7e6e979a6c46
md: avoid taking the mutex on some ioctls.

Some ioctls don't need to take the mutex and doing so can cause
a delay as it is held during super-block update.
So move those ioctls out of the mutex and rely on rcu locking
to ensure we don't access stale data.

Signed-off-by: NeilBrown <neilb@suse.de>
drivers/md/md.c