From patchwork Fri Feb 21 12:48:44 2014 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Luis Henriques X-Patchwork-Id: 322717 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 1F9A22C00AA for ; Fri, 21 Feb 2014 23:54:16 +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 1WGpcK-0002Oo-Ky; Fri, 21 Feb 2014 12:54:12 +0000 Received: from youngberry.canonical.com ([91.189.89.112]) by huckleberry.canonical.com with esmtp (Exim 4.76) (envelope-from ) id 1WGpZh-0001C0-5R for kernel-team@lists.ubuntu.com; Fri, 21 Feb 2014 12:51:29 +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 1WGpZg-00028q-VC; Fri, 21 Feb 2014 12:51:29 +0000 From: Luis Henriques To: linux-kernel@vger.kernel.org, stable@vger.kernel.org, kernel-team@lists.ubuntu.com Subject: [PATCH 3.11 100/121] block: add cond_resched() to potentially long running ioctl discard loop Date: Fri, 21 Feb 2014 12:48:44 +0000 Message-Id: <1392986945-9693-101-git-send-email-luis.henriques@canonical.com> X-Mailer: git-send-email 1.9.0 In-Reply-To: <1392986945-9693-1-git-send-email-luis.henriques@canonical.com> References: <1392986945-9693-1-git-send-email-luis.henriques@canonical.com> X-Extended-Stable: 3.11 Cc: Jens Axboe 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 3.11.10.5 -stable review patch. If anyone has any objections, please let me know. ------------------ From: Jens Axboe 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 Signed-off-by: Luis Henriques --- block/blk-lib.c | 8 ++++++++ 1 file changed, 8 insertions(+) diff --git a/block/blk-lib.c b/block/blk-lib.c index d6f50d5..9a32f58 100644 --- a/block/blk-lib.c +++ b/block/blk-lib.c @@ -121,6 +121,14 @@ 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(); } blk_finish_plug(&plug);