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 X-Spam-Level: X-Spam-Status: No, score=-5.0 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS,USER_AGENT_SANE_1 autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 4CB93C433E0 for ; Thu, 11 Jun 2020 23:47:07 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 26BFF20842 for ; Thu, 11 Jun 2020 23:47:07 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=deltatee.com header.i=@deltatee.com header.b="FkEOcxMS" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726396AbgFKXrF (ORCPT ); Thu, 11 Jun 2020 19:47:05 -0400 Received: from ale.deltatee.com ([204.191.154.188]:33110 "EHLO ale.deltatee.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726285AbgFKXrE (ORCPT ); Thu, 11 Jun 2020 19:47:04 -0400 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=deltatee.com; s=20200525; h=Subject:Content-Transfer-Encoding:Content-Type: In-Reply-To:MIME-Version:Date:Message-ID:From:References:Cc:To:Sender: Reply-To:Content-ID:Content-Description:Resent-Date:Resent-From:Resent-Sender :Resent-To:Resent-Cc:Resent-Message-ID:List-Id:List-Help:List-Unsubscribe: List-Subscribe:List-Post:List-Owner:List-Archive; bh=gV9QoHt8EYvoGCRmgXIoNP2+LNt+D1Ofl05Ii0wSJgE=; b=FkEOcxMSQTZ7+vgRXN3priANPV P8kEefsc8sUN3ssFd8os7kKyVrXhuQFyr2tdlCspviSAdVUqUDmJ45OyszmwhlUs9s+L7h5CpU8Ly jm8B4zi/dnj5S6e8SiDmOoMSupAMqvhKKEs4Gwx2zYCIi8spOjFtNRHY3OYNp6SZdJzg+HW1GhFXF DgazrnVGdBmTP35H9W1MDEVqOvRjmJcqnnJzvOnyjBNXAea1MdjOi4WBB6IU8W+B+UQIbUXn1AtyF /lsOhUfrkpBEH8gM6HfS+NUJh2EKQ4ZGHnb43wj8yuDabFtMeF+2wIYrNrCQb0NBwufoy39Uv6PL9 Q6UI9qIA==; Received: from s01060023bee90a7d.cg.shawcable.net ([24.64.145.4] helo=[192.168.0.10]) by ale.deltatee.com with esmtpsa (TLS1.3:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.92) (envelope-from ) id 1jjWuO-0002NJ-Ai; Thu, 11 Jun 2020 17:46:57 -0600 To: Chaitanya Kulkarni , "linux-kernel@vger.kernel.org" , "linux-nvme@lists.infradead.org" Cc: Christoph Hellwig , Sagi Grimberg , Keith Busch , Jens Axboe , Max Gurtovoy , Stephen Bates References: <20200514172253.6445-1-logang@deltatee.com> <20200514172253.6445-8-logang@deltatee.com> From: Logan Gunthorpe Message-ID: Date: Thu, 11 Jun 2020 17:46:54 -0600 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.8.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit X-SA-Exim-Connect-IP: 24.64.145.4 X-SA-Exim-Rcpt-To: sbates@raithlin.com, maxg@mellanox.com, axboe@fb.com, kbusch@kernel.org, sagi@grimberg.me, hch@lst.de, linux-nvme@lists.infradead.org, linux-kernel@vger.kernel.org, Chaitanya.Kulkarni@wdc.com X-SA-Exim-Mail-From: logang@deltatee.com Subject: Re: [PATCH v13 7/9] nvmet-passthru: Add passthru code to process commands X-SA-Exim-Version: 4.2.1 (built Wed, 08 May 2019 21:11:16 +0000) X-SA-Exim-Scanned: Yes (on ale.deltatee.com) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2020-06-11 5:45 p.m., Chaitanya Kulkarni wrote: > On 5/14/20 10:23 AM, Logan Gunthorpe wrote: >> + >> +static void nvmet_passthru_execute_cmd(struct nvmet_req *req) >> +{ >> + struct nvme_ctrl *ctrl = nvmet_req_passthru_ctrl(req); >> + struct nvme_ns *ns = NULL; >> + struct request *rq = NULL; >> + struct request_queue *q; >> + u32 effects; >> + u16 status; >> + int ret; >> + >> + if (likely(req->sq->qid != 0)) { >> + u32 nsid = le32_to_cpu(req->cmd->common.nsid); >> + >> + ns = nvme_find_get_ns(ctrl, nsid); >> + if (unlikely(!ns)) { >> + pr_err("failed to get passthru ns nsid:%u\n", nsid); >> + status = NVME_SC_INVALID_NS | NVME_SC_DNR; >> + goto fail_out; >> + } >> + } >> + >> + if (ns) >> + q = ns->queue; >> + else >> + q = ctrl->admin_q; > > Is it possible to avoid explicit if.. else in fast path given that the > condition exists and we can take an advantage of that, how about > following ? > > diff --git a/drivers/nvme/target/passthru.c b/drivers/nvme/target/passthru.c > index 9e71fdfbdbb3..4f8e022d254c 100644 > --- a/drivers/nvme/target/passthru.c > +++ b/drivers/nvme/target/passthru.c > @@ -84,9 +84,9 @@ static int nvmet_passthru_map_sg(struct nvmet_req > *req, struct request *rq) > static void nvmet_passthru_execute_cmd(struct nvmet_req *req) > { > struct nvme_ctrl *ctrl = nvmet_req_passthru_ctrl(req); > + struct request_queue *q = ctrl->admin_q; > struct nvme_ns *ns = NULL; > struct request *rq = NULL; > - struct request_queue *q; > u32 effects; > u16 status; > int ret; > @@ -100,12 +100,8 @@ static void nvmet_passthru_execute_cmd(struct > nvmet_req *req) > status = NVME_SC_INVALID_NS | NVME_SC_DNR; > goto fail_out; > } > - } > - > - if (ns) > q = ns->queue; > - else > - q = ctrl->admin_q; > + } > > rq = nvme_alloc_request(q, req->cmd, BLK_MQ_REQ_NOWAIT, > NVME_QID_ANY); > if (IS_ERR(rq)) { > This makes sense. Will fix for the next revision. Thanks, Logan