From patchwork Mon Jul 17 04:00:58 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Chengming Zhou X-Patchwork-Id: 13315174 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 C7971EB64DC for ; Mon, 17 Jul 2023 04:02:14 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231250AbjGQECN (ORCPT ); Mon, 17 Jul 2023 00:02:13 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:51286 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230502AbjGQECC (ORCPT ); Mon, 17 Jul 2023 00:02:02 -0400 Received: from out-17.mta0.migadu.com (out-17.mta0.migadu.com [91.218.175.17]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id BA0CE1B8 for ; Sun, 16 Jul 2023 21:01:51 -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=1689566509; 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=L62IGS5yyrINSCSaBLEOOOMpycO+zZjyfsnojgz6mDg=; b=qxiNEW0Gf1Z9a7yqlE6MdCGCZ93ZTCLqy2TQPpQqsynOcXPGx0yCxEYYdteDz8U64+tFqt j32AmN9HvZC8brL+sUv/zp5ZGOv+3y7BTWhIZS2npJ1rnQcTdhTDJ1HJl3tLW9Mb5th/J5 p/DtxG4I7FIIn2nslGxhivLDtgi8DGI= From: chengming.zhou@linux.dev To: axboe@kernel.dk, ming.lei@redhat.com, hch@lst.de, bvanassche@acm.org Cc: linux-block@vger.kernel.org, linux-kernel@vger.kernel.org, zhouchengming@bytedance.com Subject: [PATCH v4 4/4] blk-flush: reuse rq queuelist in flush state machine Date: Mon, 17 Jul 2023 12:00:58 +0800 Message-ID: <20230717040058.3993930-5-chengming.zhou@linux.dev> In-Reply-To: <20230717040058.3993930-1-chengming.zhou@linux.dev> References: <20230717040058.3993930-1-chengming.zhou@linux.dev> MIME-Version: 1.0 X-Migadu-Flow: FLOW_OUT Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org 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 --- 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 fedb39031647..e73dc22d05c1 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(&rq->queuelist, &q->requeue_list); + list_move(&rq->queuelist, &q->requeue_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 67f810857634..01e8c31db665 100644 --- a/include/linux/blk-mq.h +++ b/include/linux/blk-mq.h @@ -178,7 +178,6 @@ struct request { struct { unsigned int seq; - struct list_head list; rq_end_io_fn *saved_end_io; } flush;