Commit 12e57f59 authored Nov 24, 2015 by Ming Lei Committed by Jens Axboe Nov 23, 2015

blk-merge: warn if figured out segment number is bigger than nr_phys_segments



We had seen lots of reports of this kind issue, so add one
warnning in blk-merge, then it can be triggered easily and
avoid to depend on warning/bug from drivers.

Signed-off-by: Ming Lei <ming.lei@canonical.com>
Signed-off-by: Jens Axboe <axboe@fb.com>

parent 02e70742

block/blk-merge.c

+6 −0

Original line number	Diff line number	Diff line
		@@ -428,6 +428,12 @@ int blk_rq_map_sg(struct request_queue q, struct request rq,
		if (sg)
		sg_mark_end(sg);

		/*
		* Something must have been wrong if the figured number of
		* segment is bigger than number of req's physical segments
		*/
		WARN_ON(nsegs > rq->nr_phys_segments);

		return nsegs;
		}
		EXPORT_SYMBOL(blk_rq_map_sg);