From patchwork Tue Mar 20 02:50:03 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Sinan Kaya X-Patchwork-Id: 10296143 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id DA72B602C2 for ; Tue, 20 Mar 2018 02:56:15 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id C59F5228C9 for ; Tue, 20 Mar 2018 02:56:15 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id BA0A227B81; Tue, 20 Mar 2018 02:56:15 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-1.9 required=2.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID autolearn=ham version=3.3.1 Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.wl.linuxfoundation.org (Postfix) with ESMTPS id 2547A228C9 for ; Tue, 20 Mar 2018 02:56:15 +0000 (UTC) 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:MIME-Version:References:In-Reply-To: Message-Id:Date:Subject:To:From:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=+4Fo7d/v7vZndGCmwe0EoVa4bhh/VASbvHxX8X6X/RY=; b=BrjgNO9qHhl783 ZYu0NbI2Nb/dyYLbXUukUZye09/xDZg5rOrgUcydXe5YPD5pLqvsuv8DzEagY/l4qiior0dU7L9wJ 96yfvngrcn11+DunUerTlbzeuXLnLMJYirk8xFJUiillIKkTQscqZXgTrA3M5rBgcDG1vU8mP7FR7 IRNGD7dTMwCm6Ojvz/IsOeW6IntZDOQMMyB4HcUD+aWcLunWrJkBUMb4pMiX2Xpdzpfuhj3LuPIlL lnmxK1/L7AyEhzHZEu9dhmBO5cIDwo+88/HriGOTJJFzJBpyYmCX7KJt8femEcc+RLjyEcZuYeyY0 SDaTVZqMCzx/tgxI/eBQ==; Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.90_1 #2 (Red Hat Linux)) id 1ey7Rb-0001Yc-H4; Tue, 20 Mar 2018 02:56:11 +0000 Received: from smtp.codeaurora.org ([198.145.29.96]) by bombadil.infradead.org with esmtps (Exim 4.90_1 #2 (Red Hat Linux)) id 1ey7M0-00064R-V9 for linux-arm-kernel@lists.infradead.org; Tue, 20 Mar 2018 02:52:22 +0000 Received: by smtp.codeaurora.org (Postfix, from userid 1000) id 128A0610DC; Tue, 20 Mar 2018 02:50:19 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=codeaurora.org; s=default; t=1521514221; bh=BzM+yZJ5q9W2BAsUFgfkkR8piuqEtoYenltti8oTptg=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=OCgJsmi5nepFjISpsTQaV40oqDiSR2zDGqgeI0zjBdA9laqLMHLUAsZ260qf4nea0 I0HPgSB7jA7AAwBuGbMhV78GcE/vkyLlZFZ5I3SDJq5O4CdyH4fjFODj2LLYkChxDq EApUYFk7UaQ4/ijbj006Yyk4uEYttXJ/0wfM1bUM= Received: from drakthul.qualcomm.com (global_nat1_iad_fw.qualcomm.com [129.46.232.65]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-SHA256 (128/128 bits)) (No client certificate requested) (Authenticated sender: okaya@smtp.codeaurora.org) by smtp.codeaurora.org (Postfix) with ESMTPSA id D25546110A; Tue, 20 Mar 2018 02:50:16 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=codeaurora.org; s=default; t=1521514218; bh=BzM+yZJ5q9W2BAsUFgfkkR8piuqEtoYenltti8oTptg=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=B4nz1lhh6oIO7VqfZXv1MgJqy1jRvuz6QUixvwvypdlBppYXS3dqvKtyIv53nL0ov B8eZyNBfdVoTY70LpWk0vEz80jE0R0NNhdYahSCxU0DaQvv4lizlKkjBSa3tQITWb7 HKoUGwApJpl4DyIpsZedu4VxxaYZRUARuHgUA/Go= DMARC-Filter: OpenDMARC Filter v1.3.2 smtp.codeaurora.org D25546110A Authentication-Results: pdx-caf-mail.web.codeaurora.org; dmarc=none (p=none dis=none) header.from=codeaurora.org Authentication-Results: pdx-caf-mail.web.codeaurora.org; spf=none smtp.mailfrom=okaya@codeaurora.org From: Sinan Kaya To: linux-scsi@vger.kernel.org, timur@codeaurora.org, sulrich@codeaurora.org Subject: [PATCH v4 3/7] scsi: dpt_i2o: eliminate duplicate barriers on weakly-ordered archs Date: Mon, 19 Mar 2018 22:50:03 -0400 Message-Id: <1521514207-10695-4-git-send-email-okaya@codeaurora.org> X-Mailer: git-send-email 2.7.4 In-Reply-To: <1521514207-10695-1-git-send-email-okaya@codeaurora.org> References: <1521514207-10695-1-git-send-email-okaya@codeaurora.org> MIME-Version: 1.0 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20180319_195025_931401_92E09889 X-CRM114-Status: GOOD ( 12.12 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: "James E.J. Bottomley" , "Martin K. Petersen" , linux-arm-msm@vger.kernel.org, linux-kernel@vger.kernel.org, Sinan Kaya , Adaptec OEM Raid Solutions , linux-arm-kernel@lists.infradead.org Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.kernel.org@lists.infradead.org X-Virus-Scanned: ClamAV using ClamSMTP Code includes barrier() followed by writel(). writel() already has a barrier on some architectures like arm64. This ends up CPU observing two barriers back to back before executing the register write. Since code already has an explicit barrier call, changing writel() to writel_relaxed(). Signed-off-by: Sinan Kaya --- drivers/scsi/dpt_i2o.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/drivers/scsi/dpt_i2o.c b/drivers/scsi/dpt_i2o.c index fd172b0..3c1e64a 100644 --- a/drivers/scsi/dpt_i2o.c +++ b/drivers/scsi/dpt_i2o.c @@ -1300,7 +1300,7 @@ static s32 adpt_i2o_post_this(adpt_hba* pHba, u32* data, int len) wmb(); //post message - writel(m, pHba->post_port); + writel_relaxed(m, pHba->post_port); wmb(); return 0; @@ -1390,7 +1390,7 @@ static s32 adpt_i2o_reset_hba(adpt_hba* pHba) memcpy_toio(pHba->msg_addr_virt+m, msg, sizeof(msg)); wmb(); - writel(m, pHba->post_port); + writel_relaxed(m, pHba->post_port); wmb(); while(*status == 0){ @@ -2797,7 +2797,7 @@ static s32 adpt_send_nop(adpt_hba*pHba,u32 m) writel( 0,&msg[2]); wmb(); - writel(m, pHba->post_port); + writel_relaxed(m, pHba->post_port); wmb(); return 0; }