From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753369Ab1LTXdx (ORCPT ); Tue, 20 Dec 2011 18:33:53 -0500 Received: from mga11.intel.com ([192.55.52.93]:53809 "EHLO mga11.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752508Ab1LTXdu (ORCPT ); Tue, 20 Dec 2011 18:33:50 -0500 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="4.71,315,1320652800"; d="scan'208";a="98548160" Subject: [PATCH] block: fix blk_queue_end_tag() To: axboe@kernel.dk From: Dan Williams Cc: Tao Ma , Meelis Roos , linux-kernel@vger.kernel.org, linux-scsi@vger.kernel.org, Ed Nadolski Date: Tue, 20 Dec 2011 15:33:49 -0800 Message-ID: <20111220233117.17757.71139.stgit@localhost6.localdomain6> User-Agent: StGit/0.15-7-g9bfb-dirty MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Commit 5e081591 "block: warn if tag is greater than real_max_depth" cleaned up blk_queue_end_tag() to warn when the tag is truly invalid (greater than real_max_depth). However, it changed behavior in the tag < max_depth case to not end the request. Leading to triggering of BUG_ON(blk_queued_rq(rq)) in the request completion path: http://marc.info/?l=linux-kernel&m=132204370518629&w=2 In order to allow blk_queue_resize_tags() to shrink the tag space blk_queue_end_tag() must always complete tags with a value less than real_max_depth regardless of the current max_depth. Cc: Tao Ma Reported-by: Meelis Roos Reported-by: Ed Nadolski Signed-off-by: Dan Williams --- Functionally the same as Tao Ma's fix [1], but just moves the warn into the if() directly. [1]: http://marc.info/?l=linux-scsi&m=132439698602441&w=2 -- Dan block/blk-tag.c | 5 +++-- 1 files changed, 3 insertions(+), 2 deletions(-) diff --git a/block/blk-tag.c b/block/blk-tag.c index e74d6d1..6e61262 100644 --- a/block/blk-tag.c +++ b/block/blk-tag.c @@ -286,12 +286,13 @@ void blk_queue_end_tag(struct request_queue *q, struct request *rq) BUG_ON(tag == -1); - if (unlikely(tag >= bqt->max_depth)) { + if (WARN_ONCE(tag >= bqt->real_max_depth, + "%s: tag %d greater than tag map size: %d\n", + __func__, tag, bqt->real_max_depth)) { /* * This can happen after tag depth has been reduced. * But tag shouldn't be larger than real_max_depth. */ - WARN_ON(tag >= bqt->real_max_depth); return; }