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 bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id DDD1EC61DA4 for ; Thu, 9 Feb 2023 05:33:39 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:In-Reply-To:Content-Type: MIME-Version:References:Message-ID:Subject:Cc:To:From:Date:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=k5HQj0Bh+XTDwk2g57W/n28Fr75z+PG5d0VEdCDpyBU=; b=QvLND2cZVu0MRDq606dZbuqUSB NWPKV0dwuV+HrBV6REVaKJHDJAlG+hlZmZtAQwTUixLLvRH9B6dDPKpYKqb+gwg20uJaH8PhH5Qrw o/UVLl/oI/j2dxQIDZeN2QKKRbPdtxMaQnp/R5lEJmK/JzGc0AJOhCxoATGnMK8SfMxNwkJlMa4nq JLKEiYyCOEOl1FcbeQmkyIudTJrBithP3gca6NSskp66jmS3ZcFFIkQOMnfhRvmylcKUhSMgu0jaL kCXGKrfaUFxAgL4qVNgNcXNHtcM/H6DVK+d+sFXz+0Fk9J+QEz0mCOdfYiVnt549BWgK00xI7P39f ecq+AzLw==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1pPzYu-000DCx-Qg; Thu, 09 Feb 2023 05:33:36 +0000 Received: from verein.lst.de ([213.95.11.211]) by bombadil.infradead.org with esmtps (Exim 4.94.2 #2 (Red Hat Linux)) id 1pPzYs-000DCH-LL for linux-nvme@lists.infradead.org; Thu, 09 Feb 2023 05:33:36 +0000 Received: by verein.lst.de (Postfix, from userid 2407) id 0232867373; Thu, 9 Feb 2023 06:33:31 +0100 (CET) Date: Thu, 9 Feb 2023 06:33:30 +0100 From: Christoph Hellwig To: Hannes Reinecke Cc: Christoph Hellwig , Sagi Grimberg , Keith Busch , linux-nvme@lists.infradead.org Subject: Re: [PATCH 1/3] nvme: split __nvme_submit_sync_cmd() Message-ID: <20230209053330.GA8536@lst.de> References: <20230208151720.109130-1-hare@suse.de> <20230208151720.109130-2-hare@suse.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20230208151720.109130-2-hare@suse.de> User-Agent: Mutt/1.5.17 (2007-11-01) X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20230208_213334_862139_2610FE30 X-CRM114-Status: GOOD ( 21.71 ) X-BeenThere: linux-nvme@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "Linux-nvme" Errors-To: linux-nvme-bounces+linux-nvme=archiver.kernel.org@lists.infradead.org On Wed, Feb 08, 2023 at 04:17:18PM +0100, Hannes Reinecke wrote: > Split a __nvme_alloc_rq() function from __nvme_submit_sync_cmd() > to reduce the number of arguments. But now everyone has to call both? > 6 files changed, 83 insertions(+), 45 deletions(-) .. and the code is a lot longer. So this doesn't really seem like much of a win? > +struct request *__nvme_alloc_rq(struct request_queue *q, > + struct nvme_command *cmd, int qid, > + blk_mq_req_flags_t flags) Why the double underscore profix? Why _rq instead of _request like blk_mq_alloc_request and nvme_init_request? > { > struct request *req; > > if (qid == NVME_QID_ANY) > req = blk_mq_alloc_request(q, nvme_req_op(cmd), flags); > else > req = blk_mq_alloc_request_hctx(q, nvme_req_op(cmd), flags, > qid - 1); > + if (!IS_ERR(req)) > + nvme_init_request(req, cmd); > > + return req; And I'd at very least split out the qid case as that is substantially different and only used in very specific places. > + */ > +int __nvme_submit_sync_cmd(struct request *req, union nvme_result *result, > + void *buffer, unsigned bufflen, int at_head) > +{ > + int ret; > > if (buffer && bufflen) { > - ret = blk_rq_map_kern(q, req, buffer, bufflen, GFP_KERNEL); > + ret = blk_rq_map_kern(req->q, req, buffer, bufflen, GFP_KERNEL); > if (ret) > goto out; This new __nvme_submit_sync_cmd now consumes the request, which is an odd calling conventions. What do you think about: - passing the "union nvme_result *result" to nvme_execute_rq, and do the conditional assignment to it there, where it fits along with all the status management - make blk_rq_map_kern handle a NULL kbuf gracefully instead of doing that in a lot of the callers - just open code __nvme_submit_sync_cmd using these building blocks.