From patchwork Fri Aug 4 15:04:17 2017 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jens Axboe X-Patchwork-Id: 9881491 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id 5C4936031B for ; Fri, 4 Aug 2017 15:04:28 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 4FEC8288D1 for ; Fri, 4 Aug 2017 15:04:28 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 4496E289E1; Fri, 4 Aug 2017 15:04:28 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-6.4 required=2.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID, RCVD_IN_DNSWL_HI, RCVD_IN_SORBS_SPAM autolearn=ham version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id EB4D2288D1 for ; Fri, 4 Aug 2017 15:04:27 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751921AbdHDPE1 (ORCPT ); Fri, 4 Aug 2017 11:04:27 -0400 Received: from mail-io0-f175.google.com ([209.85.223.175]:37046 "EHLO mail-io0-f175.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752064AbdHDPE0 (ORCPT ); Fri, 4 Aug 2017 11:04:26 -0400 Received: by mail-io0-f175.google.com with SMTP id c74so6854011iod.4 for ; Fri, 04 Aug 2017 08:04:26 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel-dk.20150623.gappssmtp.com; s=20150623; h=from:to:cc:subject:date:message-id:in-reply-to:references; bh=XYDKgpObJYCIG5gwJdKrg2jNu/GaZiUbDiSRSNZVPik=; b=owUEnAata+KmSDR1wU+q1ZqBkZyZ2YcniMqxzT8g3Rfvd6AOs/ocwtH9H6JcTHUsxe GY0awVaX519Raz3+nZ2mX0taKd03yDW6ZH4+bi1MEY1ne6QWQVPAgD0UtTtmLsQ6wrYl ySme2iqu9dCJLeTtO+5azaI6oKwW+Em1qOIYP/PoLig5Y7TWffHOhFdLmtA+ebPWFrF5 xp9pHZfwdZizIIsIn1fk9v5vlY70lQ3zF2jwjEL9Yg4w6avh/48jz99J24OWF/LDI7ou r3UKKFznMQjFPcdGrIyGkcP/A+HKVBlEte/xY3KfKU70SRHPq0hK2bEIZbt+NSTnpRka xU6A== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references; bh=XYDKgpObJYCIG5gwJdKrg2jNu/GaZiUbDiSRSNZVPik=; b=XBJm/wwHg3vyExpMrwUlsWOAMFfAAps7KYoFUrjwIeMtoFRP8mbMgwM8jbxqF8zwPA onpA3AyJrN1VCHR7pUQhaggQc3C4/d7GR6nGGer7rI6KV5m5D/intolGTO4ZN0JxLG2O qu4HRg/nGQ14yQdyZ5MZorRzZmVJ+QVx80WiHSJVjTFfo3Cs8qJdoVIKjzJLyphRFG2r 8pjRYew/M6c2dinlQctwzVqYUFkq8BI44RZ/BUV8zNENAQY7w+aZlXX0QUCGdrVxD8UX SfwFDxCg4taeS2D16mV16EQQ08oICGhCsIvj8frtcr9B5owCHJqf1YCXlrXfLWg2FOmH P8/w== X-Gm-Message-State: AHYfb5guNf/oq4gM5N/FOuLLT7PZdzfmiSQmxPgsVuAPTuuVkpX1s9Ot bXImAQPLALCvC8HUVh++5Q== X-Received: by 10.107.55.198 with SMTP id e189mr3178044ioa.34.1501859065797; Fri, 04 Aug 2017 08:04:25 -0700 (PDT) Received: from localhost.localdomain ([216.160.245.98]) by smtp.gmail.com with ESMTPSA id w207sm763245itc.34.2017.08.04.08.04.24 (version=TLS1_2 cipher=ECDHE-RSA-AES128-SHA bits=128/128); Fri, 04 Aug 2017 08:04:25 -0700 (PDT) From: Jens Axboe To: linux-block@vger.kernel.org Cc: brking@linux.vnet.ibm.com, bart.vanassche@wdc.com, Jens Axboe Subject: [PATCH 1/6] blk-mq-tag: check for NULL rq when iterating tags Date: Fri, 4 Aug 2017 09:04:17 -0600 Message-Id: <1501859062-11120-2-git-send-email-axboe@kernel.dk> X-Mailer: git-send-email 2.7.4 In-Reply-To: <1501859062-11120-1-git-send-email-axboe@kernel.dk> References: <1501859062-11120-1-git-send-email-axboe@kernel.dk> Sender: linux-block-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP Since we introduced blk-mq-sched, the tags->rqs[] array has been dynamically assigned. So we need to check for NULL when iterating, since there's a window of time where the bit is set, but we haven't dynamically assigned the tags->rqs[] array position yet. This is perfectly safe, since the memory backing of the request is never going away while the device is alive. Signed-off-by: Jens Axboe Reviewed-by: Bart Van Assche Reviewed-by: Omar Sandoval --- block/blk-mq-tag.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/block/blk-mq-tag.c b/block/blk-mq-tag.c index d0be72ccb091..b856b2827157 100644 --- a/block/blk-mq-tag.c +++ b/block/blk-mq-tag.c @@ -214,7 +214,7 @@ static bool bt_iter(struct sbitmap *bitmap, unsigned int bitnr, void *data) bitnr += tags->nr_reserved_tags; rq = tags->rqs[bitnr]; - if (rq->q == hctx->queue) + if (rq && rq->q == hctx->queue) iter_data->fn(hctx, rq, iter_data->data, reserved); return true; } @@ -249,8 +249,8 @@ static bool bt_tags_iter(struct sbitmap *bitmap, unsigned int bitnr, void *data) if (!reserved) bitnr += tags->nr_reserved_tags; rq = tags->rqs[bitnr]; - - iter_data->fn(rq, iter_data->data, reserved); + if (rq) + iter_data->fn(rq, iter_data->data, reserved); return true; }