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block: Always check queue limits for cloned requests

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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: Hannes Reinecke <hare@suse.de>
Fixes: e2a60da74 ("block: Clean up special command handling logic")
Cc: stable@vger.kernel.org # 3.7+
Acked-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
This commit is contained in:
Hannes Reinecke 2015-11-26 08:46:57 +01:00 committed by Jens Axboe
parent d0a712ceb8
commit bf4e6b4e75
2 changed files with 7 additions and 15 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

21
block/blk-core.c
View File

@ -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 &&

1
include/linux/blkdev.h
View File

@ -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,