From mboxrd@z Thu Jan 1 00:00:00 1970 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 CC43CC433F5 for ; Wed, 29 Dec 2021 17:46:08 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S237522AbhL2RqI (ORCPT ); Wed, 29 Dec 2021 12:46:08 -0500 Received: from verein.lst.de ([213.95.11.211]:38348 "EHLO verein.lst.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231784AbhL2RqH (ORCPT ); Wed, 29 Dec 2021 12:46:07 -0500 Received: by verein.lst.de (Postfix, from userid 2407) id 930F068AFE; Wed, 29 Dec 2021 18:46:03 +0100 (CET) Date: Wed, 29 Dec 2021 18:46:02 +0100 From: Christoph Hellwig To: Keith Busch Cc: linux-nvme@lists.infradead.org, linux-block@vger.kernel.org, axboe@kernel.dk, hch@lst.de, sagi@grimberg.me Subject: Re: [PATCHv2 3/3] nvme-pci: fix queue_rqs list splitting Message-ID: <20211229174602.GC28058@lst.de> References: <20211227164138.2488066-1-kbusch@kernel.org> <20211227164138.2488066-3-kbusch@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20211227164138.2488066-3-kbusch@kernel.org> User-Agent: Mutt/1.5.17 (2007-11-01) Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org > + rq_list_move(rqlist, &requeue_list, req, prev, next); > + > + req = prev; > + if (!req) > + continue; Shouldn't this be a break? > + *rqlist = next; > + prev = NULL; > + } else > + prev = req; > + } I wonder if a restart label here would be a little cleaner, something like: diff --git a/drivers/nvme/host/pci.c b/drivers/nvme/host/pci.c index 992ee314e91ba..29b433fd12bdd 100644 --- a/drivers/nvme/host/pci.c +++ b/drivers/nvme/host/pci.c @@ -999,9 +999,11 @@ static bool nvme_prep_rq_batch(struct nvme_queue *nvmeq, struct request *req) static void nvme_queue_rqs(struct request **rqlist) { - struct request *req, *next, *prev = NULL; + struct request *req, *next, *prev; struct request *requeue_list = NULL; +restart: + prev = NULL; rq_list_for_each_safe(rqlist, req, next) { struct nvme_queue *nvmeq = req->mq_hctx->driver_data; @@ -1009,9 +1011,9 @@ static void nvme_queue_rqs(struct request **rqlist) /* detach 'req' and add to remainder list */ rq_list_move(rqlist, &requeue_list, req, prev, next); + if (!prev) + break; req = prev; - if (!req) - continue; } if (!next || req->mq_hctx != next->mq_hctx) { @@ -1019,9 +1021,9 @@ static void nvme_queue_rqs(struct request **rqlist) req->rq_next = NULL; nvme_submit_cmds(nvmeq, rqlist); *rqlist = next; - prev = NULL; - } else - prev = req; + goto restart; + } + prev = req; } *rqlist = requeue_list;