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: 10296127 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 68F08602C2 for ; Tue, 20 Mar 2018 02:52:14 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 5685328DA8 for ; Tue, 20 Mar 2018 02:52:14 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 4B22228F20; Tue, 20 Mar 2018 02:52:14 +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=-6.8 required=2.0 tests=BAYES_00,DKIM_SIGNED, RCVD_IN_DNSWL_HI,T_DKIM_INVALID autolearn=unavailable version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id F305928DA8 for ; Tue, 20 Mar 2018 02:52:13 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751736AbeCTCv5 (ORCPT ); Mon, 19 Mar 2018 22:51:57 -0400 Received: from smtp.codeaurora.org ([198.145.29.96]:35470 "EHLO smtp.codeaurora.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751881AbeCTCuY (ORCPT ); Mon, 19 Mar 2018 22:50:24 -0400 Received: by smtp.codeaurora.org (Postfix, from userid 1000) id 6D6626110F; Tue, 20 Mar 2018 02:50:18 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=codeaurora.org; s=default; t=1521514223; bh=BzM+yZJ5q9W2BAsUFgfkkR8piuqEtoYenltti8oTptg=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=c9ew5/ZRNuBwY+V0qYnz8mGOE0PwhWBmVR5BSQBExUbfgTY7+1tAPwAfMKK/rqph5 dwqWO0mnOQpjZ4VfSSinP7AwVniCqMCa8ll9Qraaa3s3vsOojwJnRgkQnlXKCDHDg4 ML63Vo9/wYQKOWkSSCT7I1pRwSTEzJ4w+Pzu2Fos= 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 Cc: linux-arm-msm@vger.kernel.org, linux-arm-kernel@lists.infradead.org, Sinan Kaya , Adaptec OEM Raid Solutions , "James E.J. Bottomley" , "Martin K. Petersen" , linux-kernel@vger.kernel.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 Sender: linux-scsi-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-scsi@vger.kernel.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; }