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Commit bf4e6b4e authored by Hannes Reinecke's avatar Hannes Reinecke Committed by Jens Axboe
Browse files

block: Always check queue limits for cloned requests 



When a cloned request is retried on other queues it always needs
to be checked against the queue limits of that queue.
Otherwise the calculations for nr_phys_segments might be wrong,
leading to a crash in scsi_init_sgtable().

To clarify this the patch renames blk_rq_check_limits()
to blk_cloned_rq_check_limits() and removes the symbol
export, as the new function should only be used for
cloned requests and never exported.

Cc: Mike Snitzer <snitzer@redhat.com>
Cc: Ewan Milne <emilne@redhat.com>
Cc: Jeff Moyer <jmoyer@redhat.com>
Signed-off-by: default avatarHannes Reinecke <hare@suse.de>
Fixes: e2a60da7 ("block: Clean up special command handling logic")
Cc: stable@vger.kernel.org # 3.7+
Acked-by: default avatarMike Snitzer <snitzer@redhat.com>
Signed-off-by: default avatarJens Axboe <axboe@fb.com>
parent d0a712ce

block/blk-core.c

+7 −14
Original line number Diff line number Diff line
@@ -2114,7 +2114,8 @@ blk_qc_t submit_bio(int rw, struct bio *bio) 
EXPORT_SYMBOL(submit_bio);



/**

 * blk_rq_check_limits - Helper function to check a request for the queue limit

 * blk_cloned_rq_check_limits - Helper function to check a cloned request

 *                              for new the queue limits

 * @q:  the queue

 * @rq: the request being checked

 *
@@ -2125,20 +2126,13 @@ EXPORT_SYMBOL(submit_bio); 
 *    after it is inserted to @q, it should be checked against @q before

 *    the insertion using this generic function.

 *

 *    This function should also be useful for request stacking drivers

 *    in some cases below, so export this function.

 *    Request stacking drivers like request-based dm may change the queue

 *    limits while requests are in the queue (e.g. dm's table swapping).

 *    Such request stacking drivers should check those requests against

 *    the new queue limits again when they dispatch those requests,

 *    although such checkings are also done against the old queue limits

 *    when submitting requests.

 *    limits when retrying requests on other queues. Those requests need

 *    to be checked against the new queue limits again during dispatch.

 */

int blk_rq_check_limits(struct request_queue *q, struct request *rq)

static int blk_cloned_rq_check_limits(struct request_queue *q,

				      struct request *rq)

{

	if (!rq_mergeable(rq))

		return 0;



	if (blk_rq_sectors(rq) > blk_queue_get_max_sectors(q, rq->cmd_flags)) {

		printk(KERN_ERR "%s: over max size limit.\n", __func__);

		return -EIO;
@@ -2158,7 +2152,6 @@ int blk_rq_check_limits(struct request_queue *q, struct request *rq) 


	return 0;

}

EXPORT_SYMBOL_GPL(blk_rq_check_limits);



/**

 * blk_insert_cloned_request - Helper for stacking drivers to submit a request
@@ -2170,7 +2163,7 @@ int blk_insert_cloned_request(struct request_queue *q, struct request *rq) 
	unsigned long flags;

	int where = ELEVATOR_INSERT_BACK;



	if (blk_rq_check_limits(q, rq))

	if (blk_cloned_rq_check_limits(q, rq))

		return -EIO;



	if (rq->rq_disk &&

include/linux/blkdev.h

+0 −1
Original line number Diff line number Diff line
@@ -773,7 +773,6 @@ extern void blk_rq_set_block_pc(struct request *); 
extern void blk_requeue_request(struct request_queue *, struct request *);

extern void blk_add_request_payload(struct request *rq, struct page *page,

		unsigned int len);

extern int blk_rq_check_limits(struct request_queue *q, struct request *rq);

extern int blk_lld_busy(struct request_queue *q);

extern int blk_rq_prep_clone(struct request *rq, struct request *rq_src,

			     struct bio_set *bs, gfp_t gfp_mask,