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Commit fd782a4a authored by Hugh Dickins's avatar Hugh Dickins Committed by Linus Torvalds
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[PATCH] Fix get_request nastiness 



get_request is now expected to be holding on to queue_lock, with interrupts
disabled, when it returns NULL; but one path forgot that, causing all kinds
of nastiness under swap load - badness backtraces, strange failures, BUGs.

Signed-off-by: default avatarHugh Dickins <hugh@veritas.com>
Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
parent 541cecac

drivers/block/ll_rw_blk.c

+2 −3
Original line number Diff line number Diff line
@@ -1917,10 +1917,9 @@ static struct request *get_request(request_queue_t *q, int rw, struct bio *bio, 
	 * limit of requests, otherwise we could have thousands of requests

	 * allocated with any setting of ->nr_requests

	 */

	if (rl->count[rw] >= (3 * q->nr_requests / 2)) {

		spin_unlock_irq(q->queue_lock);

	if (rl->count[rw] >= (3 * q->nr_requests / 2))

		goto out;

	}



	rl->count[rw]++;

	rl->starved[rw] = 0;

	if (rl->count[rw] >= queue_congestion_on_threshold(q))