3.10-stable review patch. If anyone has any objections, please let me know.
------------------
From: Heiko Carstens <heiko.carstens@xxxxxxxxxx>
commit ef0899410ff630b2e75306da49996dbbfa318165 upstream.
"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@xxxxxxx>
Cc: Jens Axboe <axboe@xxxxxxxxx>
Signed-off-by: Heiko Carstens <heiko.carstens@xxxxxxxxxx>
Signed-off-by: Jens Axboe <axboe@xxxxxxxxx>
Cc: Christian Borntraeger <christian@xxxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/s390/block/dasd.c | 8 ++++----
1 file changed, 4 insertions(+), 4 deletions(-)
--- a/drivers/s390/block/dasd.c
+++ b/drivers/s390/block/dasd.c
@@ -2879,12 +2879,12 @@ static int dasd_alloc_queue(struct dasd_
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;
}
/*
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