tree 220802e0b80df5b3191359cf09effcfae84718a5
parent eb1c160b22655fd4ec44be732d6594fd1b1e44f4
author Tomoki Sekiyama <tomoki.sekiyama@hds.com> 1381876939 -0600
committer Jens Axboe <axboe@kernel.dk> 1383926413 -0700

elevator: acquire q->sysfs_lock in elevator_change()

Add locking of q->sysfs_lock into elevator_change() (an exported function)
to ensure it is held to protect q->elevator from elevator_init(), even if
elevator_change() is called from non-sysfs paths.
sysfs path (elv_iosched_store) uses __elevator_change(), non-locking
version, as the lock is already taken by elv_iosched_store().

Signed-off-by: Tomoki Sekiyama <tomoki.sekiyama@hds.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>