path: root/block
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authorHannes Reinecke <>2015-11-26 08:46:57 +0100
committerJens Axboe <>2015-11-29 14:37:27 -0700
commitbf4e6b4e757488dee1b6a581f49c7ac34cd217f8 (patch)
tree95e32c168d7478d0f541b5d19d1edf0e3d1160f1 /block
parentd0a712ceb83ebaea32d520825ee7b997f59b168f (diff)
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: # 3.7+ Acked-by: Mike Snitzer <> Signed-off-by: Jens Axboe <>
Diffstat (limited to 'block')
1 files changed, 7 insertions, 14 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)
- * 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;
* 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;
- if (blk_rq_check_limits(q, rq))
+ if (blk_cloned_rq_check_limits(q, rq))
return -EIO;
if (rq->rq_disk &&