From patchwork Fri May 12 09:35:51 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Yu Kuai X-Patchwork-Id: 13238948 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 3CCDFC77B7C for ; Fri, 12 May 2023 09:38:46 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S240354AbjELJio (ORCPT ); Fri, 12 May 2023 05:38:44 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:35182 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S240409AbjELJin (ORCPT ); Fri, 12 May 2023 05:38:43 -0400 Received: from dggsgout12.his.huawei.com (dggsgout12.his.huawei.com [45.249.212.56]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 8B48C106C8; Fri, 12 May 2023 02:38:41 -0700 (PDT) Received: from mail02.huawei.com (unknown [172.30.67.143]) by dggsgout12.his.huawei.com (SkyGuard) with ESMTP id 4QHkGj0fyJz4f402s; Fri, 12 May 2023 17:38:37 +0800 (CST) Received: from huaweicloud.com (unknown [10.175.104.67]) by APP2 (Coremail) with SMTP id Syh0CgA33eoZCV5k66u5JA--.8346S7; Fri, 12 May 2023 17:38:38 +0800 (CST) From: Yu Kuai To: hch@lst.de, tj@kernel.org, josef@toxicpanda.com, axboe@kernel.dk, yukuai3@huawei.com Cc: lukas.bulwahn@gmail.com, cgroups@vger.kernel.org, linux-block@vger.kernel.org, linux-kernel@vger.kernel.org, yukuai1@huaweicloud.com, yi.zhang@huawei.com, yangerkun@huawei.com Subject: [PATCH -next v2 3/6] blk-wbt: remove dead code to handle wbt enable/disable with io inflight Date: Fri, 12 May 2023 17:35:51 +0800 Message-Id: <20230512093554.911753-4-yukuai1@huaweicloud.com> X-Mailer: git-send-email 2.39.2 In-Reply-To: <20230512093554.911753-1-yukuai1@huaweicloud.com> References: <20230512093554.911753-1-yukuai1@huaweicloud.com> MIME-Version: 1.0 X-CM-TRANSID: Syh0CgA33eoZCV5k66u5JA--.8346S7 X-Coremail-Antispam: 1UD129KBjvJXoW7Kr17uFyrCrWUWF4DuFW3Wrg_yoW8Xw15pr W3C34qkFsFqFn29anFqr4xXrWayw4kGryxGFW5CrZxZr1UCr1a9F97Wr109a4FvrWFkanI gr1I9FyrCF4rJ3DanT9S1TB71UUUUUUqnTZGkaVYY2UrUUUUjbIjqfuFe4nvWSU5nxnvy2 9KBjDU0xBIdaVrnRJUUUPj14x267AKxVWrJVCq3wAFc2x0x2IEx4CE42xK8VAvwI8IcIk0 rVWrJVCq3wAFIxvE14AKwVWUJVWUGwA2048vs2IY020E87I2jVAFwI0_JrWl82xGYIkIc2 x26xkF7I0E14v26ryj6s0DM28lY4IEw2IIxxk0rwA2F7IY1VAKz4vEj48ve4kI8wA2z4x0 Y4vE2Ix0cI8IcVAFwI0_tr0E3s1l84ACjcxK6xIIjxv20xvEc7CjxVAFwI0_Gr1j6F4UJw A2z4x0Y4vEx4A2jsIE14v26rxl6s0DM28EF7xvwVC2z280aVCY1x0267AKxVW0oVCq3wAS 0I0E0xvYzxvE52x082IY62kv0487Mc02F40EFcxC0VAKzVAqx4xG6I80ewAv7VC0I7IYx2 IY67AKxVWUJVWUGwAv7VC2z280aVAFwI0_Jr0_Gr1lOx8S6xCaFVCjc4AY6r1j6r4UM4x0 Y48IcxkI7VAKI48JM4x0x7Aq67IIx4CEVc8vx2IErcIFxwACI402YVCY1x02628vn2kIc2 xKxwCF04k20xvY0x0EwIxGrwCFx2IqxVCFs4IE7xkEbVWUJVW8JwC20s026c02F40E14v2 6r1j6r18MI8I3I0E7480Y4vE14v26r106r1rMI8E67AF67kF1VAFwI0_Jw0_GFylIxkGc2 Ij64vIr41lIxAIcVC0I7IYx2IY67AKxVWUJVWUCwCI42IY6xIIjxv20xvEc7CjxVAFwI0_ Gr0_Cr1lIxAIcVCF04k26cxKx2IYs7xG6r1j6r1xMIIF0xvEx4A2jsIE14v26r4j6F4UMI IF0xvEx4A2jsIEc7CjxVAFwI0_Gr1j6F4UJbIYCTnIWIevJa73UjIFyTuYvjfUojjgUUUU U X-CM-SenderInfo: 51xn3trlr6x35dzhxuhorxvhhfrp/ X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org From: Yu Kuai enable or disable wbt is always called with queue freezed, so that wbt can never be enabled or disabled while io is still inflight, and this behaviour should always hold to avoid io hang(There have been reported several times). Therefor, the code to handle wbt enable/diskble with io inflight is not and never will be used, hence remove such dead code. Signed-off-by: Yu Kuai Reviewed-by: Christoph Hellwig --- block/blk-wbt.c | 16 ---------------- 1 file changed, 16 deletions(-) diff --git a/block/blk-wbt.c b/block/blk-wbt.c index 9ec2a2f1eda3..cb464c572840 100644 --- a/block/blk-wbt.c +++ b/block/blk-wbt.c @@ -200,15 +200,6 @@ static void wbt_rqw_done(struct rq_wb *rwb, struct rq_wait *rqw, inflight = atomic_dec_return(&rqw->inflight); - /* - * wbt got disabled with IO in flight. Wake up any potential - * waiters, we don't have to do more than that. - */ - if (unlikely(!rwb_enabled(rwb))) { - rwb_wake_all(rwb); - return; - } - /* * For discards, our limit is always the background. For writes, if * the device does write back caching, drop further down before we @@ -545,13 +536,6 @@ static inline unsigned int get_limit(struct rq_wb *rwb, blk_opf_t opf) { unsigned int limit; - /* - * If we got disabled, just return UINT_MAX. This ensures that - * we'll properly inc a new IO, and dec+wakeup at the end. - */ - if (!rwb_enabled(rwb)) - return UINT_MAX; - if ((opf & REQ_OP_MASK) == REQ_OP_DISCARD) return rwb->wb_background;