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[2620:137:e000::1:20]) by mx.google.com with ESMTP id o20-20020a17090b0c9400b00263b9233a57si1632156pjz.64.2023.07.07.02.52.28; Fri, 07 Jul 2023 02:52:41 -0700 (PDT) Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20; Authentication-Results: mx.google.com; dkim=pass header.i=@linux.dev header.s=key1 header.b=k7qzuLrF; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=linux.dev Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232782AbjGGJjh (ORCPT + 99 others); Fri, 7 Jul 2023 05:39:37 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:53308 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232728AbjGGJja (ORCPT ); Fri, 7 Jul 2023 05:39:30 -0400 Received: from out-43.mta0.migadu.com (out-43.mta0.migadu.com [91.218.175.43]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id B11CB2128 for ; Fri, 7 Jul 2023 02:39:16 -0700 (PDT) X-Report-Abuse: Please report any abuse attempt to abuse@migadu.com and include these headers. DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.dev; s=key1; t=1688722754; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=znByHfzQSpvrPQaReH7yflCmK5TREu8Z0tH8P3jgNog=; b=k7qzuLrFyLTHZjTplLwK1pIMWbb8ID0RsNUs4Ol1S8PtEC8M5suueKCd3IbrWN5ymFPn7L nJb+qDCU2VhjmBkz7x9+mo5G5TP4+RPaHNpqlbB807FYEBzpT5x7zerC5w8JMfDl0HLH20 ZkBK7AQ8c03WwQMbsn4KP4k8L1ZAzrI= From: chengming.zhou@linux.dev To: axboe@kernel.dk, ming.lei@redhat.com, hch@lst.de, tj@kernel.org Cc: linux-block@vger.kernel.org, linux-kernel@vger.kernel.org, zhouchengming@bytedance.com Subject: [PATCH v3 4/4] blk-flush: reuse rq queuelist in flush state machine Date: Fri, 7 Jul 2023 17:37:22 +0800 Message-ID: <20230707093722.1338589-5-chengming.zhou@linux.dev> In-Reply-To: <20230707093722.1338589-1-chengming.zhou@linux.dev> References: <20230707093722.1338589-1-chengming.zhou@linux.dev> MIME-Version: 1.0 X-Migadu-Flow: FLOW_OUT X-Spam-Status: No, score=-2.1 required=5.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF,SPF_HELO_NONE,SPF_PASS, T_SCC_BODY_TEXT_LINE,URIBL_BLOCKED autolearn=unavailable autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on lindbergh.monkeyblade.net Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org X-getmail-retrieved-from-mailbox: =?utf-8?q?INBOX?= X-GMAIL-THRID: =?utf-8?q?1770754996878111717?= X-GMAIL-MSGID: =?utf-8?q?1770754996878111717?= From: Chengming Zhou Since we don't need to maintain inflight flush_data requests list anymore, we can reuse rq->queuelist for flush pending list. Note in mq_flush_data_end_io(), we need to re-initialize rq->queuelist before reusing it in the state machine when end, since the rq->rq_next also reuse it, may have corrupted rq->queuelist by the driver. This patch decrease the size of struct request by 16 bytes. Signed-off-by: Chengming Zhou Reviewed-by: Christoph Hellwig Reviewed-by: Ming Lei --- v3: - fix a bug report of blktests nvme/012, we need to re-initialize rq->queuelist before reusing it in the state machine when end. Because rq->rq_next reuse may have corrupted it. Thanks Ming Lei. --- block/blk-flush.c | 17 ++++++++++------- include/linux/blk-mq.h | 1 - 2 files changed, 10 insertions(+), 8 deletions(-) diff --git a/block/blk-flush.c b/block/blk-flush.c index bb7adfc2a5da..4826d2d61a23 100644 --- a/block/blk-flush.c +++ b/block/blk-flush.c @@ -183,14 +183,13 @@ static void blk_flush_complete_seq(struct request *rq, /* queue for flush */ if (list_empty(pending)) fq->flush_pending_since = jiffies; - list_move_tail(&rq->flush.list, pending); + list_move_tail(&rq->queuelist, pending); break; case REQ_FSEQ_DATA: - list_del_init(&rq->flush.list); fq->flush_data_in_flight++; spin_lock(&q->requeue_lock); - list_add_tail(&rq->queuelist, &q->flush_list); + list_move_tail(&rq->queuelist, &q->flush_list); spin_unlock(&q->requeue_lock); blk_mq_kick_requeue_list(q); break; @@ -202,7 +201,7 @@ static void blk_flush_complete_seq(struct request *rq, * flush data request completion path. Restore @rq for * normal completion and end it. */ - list_del_init(&rq->flush.list); + list_del_init(&rq->queuelist); blk_flush_restore_request(rq); blk_mq_end_request(rq, error); break; @@ -258,7 +257,7 @@ static enum rq_end_io_ret flush_end_io(struct request *flush_rq, fq->flush_running_idx ^= 1; /* and push the waiting requests to the next stage */ - list_for_each_entry_safe(rq, n, running, flush.list) { + list_for_each_entry_safe(rq, n, running, queuelist) { unsigned int seq = blk_flush_cur_seq(rq); BUG_ON(seq != REQ_FSEQ_PREFLUSH && seq != REQ_FSEQ_POSTFLUSH); @@ -292,7 +291,7 @@ static void blk_kick_flush(struct request_queue *q, struct blk_flush_queue *fq, { struct list_head *pending = &fq->flush_queue[fq->flush_pending_idx]; struct request *first_rq = - list_first_entry(pending, struct request, flush.list); + list_first_entry(pending, struct request, queuelist); struct request *flush_rq = fq->flush_rq; /* C1 described at the top of this file */ @@ -376,6 +375,11 @@ static enum rq_end_io_ret mq_flush_data_end_io(struct request *rq, */ spin_lock_irqsave(&fq->mq_flush_lock, flags); fq->flush_data_in_flight--; + /* + * May have been corrupted by rq->rq_next reuse, we need to + * re-initialize rq->queuelist before reusing it here. + */ + INIT_LIST_HEAD(&rq->queuelist); blk_flush_complete_seq(rq, fq, REQ_FSEQ_DATA, error); spin_unlock_irqrestore(&fq->mq_flush_lock, flags); @@ -386,7 +390,6 @@ static enum rq_end_io_ret mq_flush_data_end_io(struct request *rq, static void blk_rq_init_flush(struct request *rq) { rq->flush.seq = 0; - INIT_LIST_HEAD(&rq->flush.list); rq->rq_flags |= RQF_FLUSH_SEQ; rq->flush.saved_end_io = rq->end_io; /* Usually NULL */ rq->end_io = mq_flush_data_end_io; diff --git a/include/linux/blk-mq.h b/include/linux/blk-mq.h index 34d400171b3e..ab790eba5fcf 100644 --- a/include/linux/blk-mq.h +++ b/include/linux/blk-mq.h @@ -176,7 +176,6 @@ struct request { struct { unsigned int seq; - struct list_head list; rq_end_io_fn *saved_end_io; } flush;