From patchwork Fri Feb 21 12:59:52 2014 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Luis Henriques X-Patchwork-Id: 322796 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Received: from huckleberry.canonical.com (huckleberry.canonical.com [91.189.94.19]) by ozlabs.org (Postfix) with ESMTP id 1A3EA2C00CC for ; Sat, 22 Feb 2014 00:01:51 +1100 (EST) Received: from localhost ([127.0.0.1] helo=huckleberry.canonical.com) by huckleberry.canonical.com with esmtp (Exim 4.76) (envelope-from ) id 1WGpjf-0005Jv-7n; Fri, 21 Feb 2014 13:01:47 +0000 Received: from youngberry.canonical.com ([91.189.89.112]) by huckleberry.canonical.com with esmtp (Exim 4.76) (envelope-from ) id 1WGphq-0004YV-CL for kernel-team@lists.ubuntu.com; Fri, 21 Feb 2014 12:59:54 +0000 Received: from bl20-128-115.dsl.telepac.pt ([2.81.128.115] helo=localhost) by youngberry.canonical.com with esmtpsa (TLS1.0:DHE_RSA_AES_128_CBC_SHA1:16) (Exim 4.71) (envelope-from ) id 1WGphq-0002Uk-3q; Fri, 21 Feb 2014 12:59:54 +0000 From: Luis Henriques To: Jens Axboe Subject: [3.5.y.z extended stable] Patch "block: add cond_resched() to potentially long running ioctl discard" has been added to staging queue Date: Fri, 21 Feb 2014 12:59:52 +0000 Message-Id: <1392987592-15046-1-git-send-email-luis.henriques@canonical.com> X-Mailer: git-send-email 1.9.0 X-Extended-Stable: 3.5 Cc: kernel-team@lists.ubuntu.com X-BeenThere: kernel-team@lists.ubuntu.com X-Mailman-Version: 2.1.14 Precedence: list List-Id: Kernel team discussions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , MIME-Version: 1.0 Errors-To: kernel-team-bounces@lists.ubuntu.com Sender: kernel-team-bounces@lists.ubuntu.com This is a note to let you know that I have just added a patch titled block: add cond_resched() to potentially long running ioctl discard to the linux-3.5.y-queue branch of the 3.5.y.z extended stable tree which can be found at: http://kernel.ubuntu.com/git?p=ubuntu/linux.git;a=shortlog;h=refs/heads/linux-3.5.y-queue If you, or anyone else, feels it should not be added to this tree, please reply to this email. For more information about the 3.5.y.z tree, see https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable Thanks. -Luis ------ From f92ffa2228c68c6f59711043ee4649c422cf1e9b Mon Sep 17 00:00:00 2001 From: Jens Axboe Date: Wed, 12 Feb 2014 09:34:01 -0700 Subject: block: add cond_resched() to potentially long running ioctl discard loop commit c8123f8c9cb517403b51aa41c3c46ff5e10b2c17 upstream. When mkfs issues a full device discard and the device only supports discards of a smallish size, we can loop in blkdev_issue_discard() for a long time. If preempt isn't enabled, this can turn into a softlock situation and the kernel will start complaining. Add an explicit cond_resched() at the end of the loop to avoid that. Signed-off-by: Jens Axboe [ luis: backported to 3.5: adjusted context ] Signed-off-by: Luis Henriques --- block/blk-lib.c | 8 ++++++++ 1 file changed, 8 insertions(+) -- 1.9.0 diff --git a/block/blk-lib.c b/block/blk-lib.c index 2b461b4..36751e2 100644 --- a/block/blk-lib.c +++ b/block/blk-lib.c @@ -101,6 +101,14 @@ int blkdev_issue_discard(struct block_device *bdev, sector_t sector, atomic_inc(&bb.done); submit_bio(type, bio); + + /* + * We can loop for a long time in here, if someone does + * full device discards (like mkfs). Be nice and allow + * us to schedule out to avoid softlocking if preempt + * is disabled. + */ + cond_resched(); } /* Wait for bios in-flight */