| From | Greg Kroah-Hartman <> | Subject | [PATCH 3.10 75/85] s390/dasd: hold request queue sysfs lock when calling elevator_init() | Date | Thu, 20 Mar 2014 17:10:18 -0700 |
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3.10-stable review patch. If anyone has any objections, please let me know.
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From: Heiko Carstens <heiko.carstens@de.ibm.com>
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@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> Cc: Christian Borntraeger <christian@borntraeger.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
--- 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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