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=-2.2 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=no 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 C5757C47253 for ; Fri, 1 May 2020 12:54:27 +0000 (UTC) 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 mail.kernel.org (Postfix) with ESMTPS id 95479208D6 for ; Fri, 1 May 2020 12:54:27 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="iOQ39lOb" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 95479208D6 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=lst.de Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-nvme-bounces+linux-nvme=archiver.kernel.org@lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20170209; h=Sender: Content-Transfer-Encoding:Content-Type:Cc:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:References: Message-ID:Subject:To:From:Date:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=IVjQ11iucGBLtbns5OuPgIwI5T5MZq/TDRCJ6FohRDM=; b=iOQ39lObYmvL80 dGXZW0rNqmsMPJdn8Ir21gxUWoOMBubF74iwvZZE9anHzWfNX2esV2GIMePYUuZqDf/fDFPZ4Krn1 esG/J/H6i0u5F4VX1coDfdFmhPSA01u2sxGFc9ZeZEzDI8zqobypn1Hr5WdEARJ5AovSvUxatsMh0 m4bq4yNhM7g6IdBC4qtOM2Ks6w1VwYAeBLi9tJPKetSDy5eDPUkPpQX7HO3O+b75pQgYkTB41QBPB ePjFmjGzJ80rz/EHkR6MbgsWfKE242YaTP+NuXWt4s0UoNonip1Ts2fOVoM6SuMFpWvA51gsOzT6A Q///fbVFNJDJs4J60N1A==; Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1jUVBR-0004dR-Pu; Fri, 01 May 2020 12:54:25 +0000 Received: from verein.lst.de ([213.95.11.211]) by bombadil.infradead.org with esmtps (Exim 4.92.3 #3 (Red Hat Linux)) id 1jUVBP-0004d6-8U for linux-nvme@lists.infradead.org; Fri, 01 May 2020 12:54:24 +0000 Received: by verein.lst.de (Postfix, from userid 2407) id 94A3068BFE; Fri, 1 May 2020 14:54:20 +0200 (CEST) Date: Fri, 1 May 2020 14:54:20 +0200 From: Christoph Hellwig To: Keith Busch Subject: Re: [PATCH 2/3] nvme-pci: remove cached shadow doorbell offsets Message-ID: <20200501125420.GB5197@lst.de> References: <20200427235243.2268765-1-kbusch@kernel.org> <20200427235243.2268765-2-kbusch@kernel.org> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20200427235243.2268765-2-kbusch@kernel.org> 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-20200501_055423_448245_CE64794E X-CRM114-Status: GOOD ( 11.14 ) X-BeenThere: linux-nvme@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: hch@lst.de, linux-nvme@lists.infradead.org, sagi@grimberg.me Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-nvme" Errors-To: linux-nvme-bounces+linux-nvme=archiver.kernel.org@lists.infradead.org This doesn't actually apply. Some comments below anyway: > +static bool nvme_dbbuf_update_sq(struct nvme_queue *nvmeq) > +{ > + struct nvme_dev *dev = nvmeq->dev; > > + if (!dev->dbbuf_dbs) > + return true; I'd rather have this check in the caller. That makes it both more obvious to read, and avoids a function call for the fast path. > +static bool nvme_dbbuf_update_cq(struct nvme_queue *nvmeq) > +{ > + struct nvme_dev *dev = nvmeq->dev; > + > + if (!dev->dbbuf_dbs) > + return true; Same here. > static inline void nvme_write_sq_db(struct nvme_queue *nvmeq) > { > + if (nvme_dbbuf_update_sq(nvmeq)) > writel(nvmeq->sq_tail, nvmeq->q_db); > } It might be worth to just open code this in the two callers, even if the additional check I suggested above. > > @@ -918,11 +918,8 @@ static inline bool nvme_cqe_pending(struct nvme_queue *nvmeq) > > static inline void nvme_ring_cq_doorbell(struct nvme_queue *nvmeq) > { > + if (nvme_dbbuf_update_cq(nvmeq)) > + writel(nvmeq->cq_head, nvmeq->q_db + nvmeq->dev->db_stride); Same here for the only caller. _______________________________________________ linux-nvme mailing list linux-nvme@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-nvme