From bf4e6b4e757488dee1b6a581f49c7ac34cd217f8 Mon Sep 17 00:00:00 2001 From: Hannes Reinecke Date: Thu, 26 Nov 2015 08:46:57 +0100 Subject: [PATCH] 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 Cc: Ewan Milne Cc: Jeff Moyer Signed-off-by: Hannes Reinecke Fixes: e2a60da74 ("block: Clean up special command handling logic") Cc: stable@vger.kernel.org # 3.7+ Acked-by: Mike Snitzer Signed-off-by: Jens Axboe --- block/blk-core.c | 21 +++++++-------------- include/linux/blkdev.h | 1 - 2 files changed, 7 insertions(+), 15 deletions(-) diff --git a/block/blk-core.c b/block/blk-core.c index 5131993b23a1..a0af4043dda2 100644 --- a/block/blk-core.c +++ b/block/blk-core.c @@ -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 && diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h index c0d2b7927c1f..c06f8eaa42ff 100644 --- a/include/linux/blkdev.h +++ b/include/linux/blkdev.h @@ -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,