From mboxrd@z Thu Jan 1 00:00:00 1970 From: Mike Snitzer Subject: [PATCH v2] dm mpath: revert "dm: Call blk_abort_queue on failed paths" Date: Mon, 22 Nov 2010 20:00:25 -0500 Message-ID: <20101123010025.GA18584@redhat.com> References: <20101118201841.GE30435@agk-dp.fab.redhat.com> <1290116896-18209-1-git-send-email-snitzer@redhat.com> Reply-To: device-mapper development Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Content-Disposition: inline In-Reply-To: <1290116896-18209-1-git-send-email-snitzer@redhat.com> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: dm-devel-bounces@redhat.com Errors-To: dm-devel-bounces@redhat.com To: dm-devel@redhat.com Cc: Mike Christie , Mike Anderson List-Id: dm-devel.ids This reverts commit 224cb3e981f1b2f9f93dbd49eaef505d17d894c2. Multipath was previously made to use blk_abort_queue() to allow for lower latency path deactivation. The call to blk_abort_queue has proven to be unsafe due to a race (between blk_abort_queue and scsi_request_fn) that can lead to list corruption, from: https://www.redhat.com/archives/dm-devel/2010-November/msg00085.html "the cmd gets blk_abort_queued/timedout run on it and the scsi eh somehow is able to complete and run scsi_queue_insert while scsi_request_fn is still trying to process the request." Signed-off-by: Mike Snitzer Cc: Mike Anderson Cc: Mike Christie --- drivers/md/dm-mpath.c | 12 ------------ 1 file changed, 12 deletions(-) v2: revert commit rather than #if 0 the code in question Index: linux-2.6/drivers/md/dm-mpath.c =================================================================== --- linux-2.6.orig/drivers/md/dm-mpath.c +++ linux-2.6/drivers/md/dm-mpath.c @@ -33,7 +33,6 @@ struct pgpath { unsigned fail_count; /* Cumulative failure count */ struct dm_path path; - struct work_struct deactivate_path; struct work_struct activate_path; }; @@ -116,7 +115,6 @@ static struct workqueue_struct *kmultipa static void process_queued_ios(struct work_struct *work); static void trigger_event(struct work_struct *work); static void activate_path(struct work_struct *work); -static void deactivate_path(struct work_struct *work); /*----------------------------------------------- @@ -129,7 +127,6 @@ static struct pgpath *alloc_pgpath(void) if (pgpath) { pgpath->is_active = 1; - INIT_WORK(&pgpath->deactivate_path, deactivate_path); INIT_WORK(&pgpath->activate_path, activate_path); } @@ -141,14 +138,6 @@ static void free_pgpath(struct pgpath *p kfree(pgpath); } -static void deactivate_path(struct work_struct *work) -{ - struct pgpath *pgpath = - container_of(work, struct pgpath, deactivate_path); - - blk_abort_queue(pgpath->path.dev->bdev->bd_disk->queue); -} - static struct priority_group *alloc_priority_group(void) { struct priority_group *pg; @@ -995,7 +984,6 @@ static int fail_path(struct pgpath *pgpa pgpath->path.dev->name, m->nr_valid_paths); schedule_work(&m->trigger_event); - queue_work(kmultipathd, &pgpath->deactivate_path); out: spin_unlock_irqrestore(&m->lock, flags);