s390/dasd: hold request queue sysfs lock when calling elevator_init()
"elevator: Fix a race in elevator switching and md device initialization"
changed the semantics of elevator_init() in a way that now enforces to hold
the corresponding request queue's sysfs_lock when calling elevator_init()
to fix a race.
The patch did not convert the s390 dasd device driver which is the only
device driver which also calls elevator_init(). So add the missing locking.
Cc: Tomoki Sekiyama <tomoki.sekiyama@hds.com>
Cc: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
diff --git a/drivers/s390/block/dasd.c b/drivers/s390/block/dasd.c
index 451bf99..846d5c6 100644
--- a/drivers/s390/block/dasd.c
+++ b/drivers/s390/block/dasd.c
@@ -2978,12 +2978,12 @@
elevator_exit(block->request_queue->elevator);
block->request_queue->elevator = NULL;
+ mutex_lock(&block->request_queue->sysfs_lock);
rc = elevator_init(block->request_queue, "deadline");
- if (rc) {
+ if (rc)
blk_cleanup_queue(block->request_queue);
- return rc;
- }
- return 0;
+ mutex_unlock(&block->request_queue->sysfs_lock);
+ return rc;
}
/*
