Commit 7aef2e78 authored Sep 11, 2013 by Jianpeng Ma Committed by Jens Axboe Sep 11, 2013

block: trace all devices plug operation



In func blk_queue_bio, if list of plug is empty,it will call
blk_trace_plug.
If process deal with a single device,it't ok.But if process deal with
multi devices,it only trace the first device.
Using request_count to judge, it can soleve this problem.

In addition, i modify the comment.

Signed-off-by: Jianpeng Ma <majianpeng@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

parent 6e466452

block/blk-core.c

+2 −4

Original line number	Diff line number	Diff line
		@@ -1549,11 +1549,9 @@ void blk_queue_bio(struct request_queue q, struct bio bio)
		if (plug) {
		/*
		* If this is the first request added after a plug, fire
		* of a plug trace. If others have been added before, check
		* if we have multiple devices in this plug. If so, make a
		* note to sort the list before dispatch.
		* of a plug trace.
		*/
		if (list_empty(&plug->list))
		if (!request_count)
		trace_block_plug(q);
		else {
		if (request_count >= BLK_MAX_REQUEST_COUNT) {