From patchwork Tue Mar 20 02:50:04 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Sinan Kaya X-Patchwork-Id: 10296101 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 E5057602C2 for ; Tue, 20 Mar 2018 02:51:16 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id D730928DA8 for ; Tue, 20 Mar 2018 02:51:16 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id CBF5128F76; Tue, 20 Mar 2018 02:51:16 +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 4A89A28DA8 for ; Tue, 20 Mar 2018 02:51:16 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751920AbeCTCue (ORCPT ); Mon, 19 Mar 2018 22:50:34 -0400 Received: from smtp.codeaurora.org ([198.145.29.96]:35578 "EHLO smtp.codeaurora.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752130AbeCTCu0 (ORCPT ); Mon, 19 Mar 2018 22:50:26 -0400 Received: by smtp.codeaurora.org (Postfix, from userid 1000) id 18B9360C54; Tue, 20 Mar 2018 02:50:21 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=codeaurora.org; s=default; t=1521514225; bh=jQZTqieZcLriv2HRSE7I8uYGB92GghxDNdQO7u3qq20=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=BgpO75qbbJg/vR/1MpDoqR8/Qup01Q2h/lwhcNjtFKoW5uCd6IXrEdOHcFybiuqkB tUyTTYopCQVfGlXyvwxHrJAqsF9GHgJZ8o3VdgVEQL5zRvppwwokpu54rSuVflfHI/ TQVpyDRli/d7OExPrd6lc9kumju/rc+qFTtOq/E8= 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 C59DC60FEF; 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=1521514220; bh=jQZTqieZcLriv2HRSE7I8uYGB92GghxDNdQO7u3qq20=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=VkDHCfgEnj0qqRkL2wQ/CL6tOUgdAYLm9slQpy0CNAjEVBxkkWI/CBs1P13gd3onN Q+vNBvBlofIkVxRfi1Abqzva1kZ9ukVr9hefa+WYgvP8utGp+uZT18MpZAb77LJEVU j2hgDdXUk7ppqjYFW8DLxqofK7Y2Sz8WvnOYMDAk= DMARC-Filter: OpenDMARC Filter v1.3.2 smtp.codeaurora.org C59DC60FEF 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 , James Smart , Dick Kennedy , "James E.J. Bottomley" , "Martin K. Petersen" , linux-kernel@vger.kernel.org Subject: [PATCH v4 4/7] scsi: lpfc: Eliminate duplicate barriers on weakly-ordered archs Date: Mon, 19 Mar 2018 22:50:04 -0400 Message-Id: <1521514207-10695-5-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/lpfc/lpfc_sli.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/drivers/scsi/lpfc/lpfc_sli.c b/drivers/scsi/lpfc/lpfc_sli.c index 5f5528a..7dae7d3 100644 --- a/drivers/scsi/lpfc/lpfc_sli.c +++ b/drivers/scsi/lpfc/lpfc_sli.c @@ -1647,7 +1647,7 @@ lpfc_sli_update_full_ring(struct lpfc_hba *phba, struct lpfc_sli_ring *pring) * Set ring 'ringno' to SET R0CE_REQ in Chip Att register. * The HBA will tell us when an IOCB entry is available. */ - writel((CA_R0ATT|CA_R0CE_REQ) << (ringno*4), phba->CAregaddr); + writel_relaxed((CA_R0ATT|CA_R0CE_REQ) << (ringno*4), phba->CAregaddr); readl(phba->CAregaddr); /* flush */ pring->stats.iocb_cmd_full++; @@ -1672,7 +1672,7 @@ lpfc_sli_update_ring(struct lpfc_hba *phba, struct lpfc_sli_ring *pring) */ if (!(phba->sli3_options & LPFC_SLI3_CRP_ENABLED)) { wmb(); - writel(CA_R0ATT << (ringno * 4), phba->CAregaddr); + writel_relaxed(CA_R0ATT << (ringno * 4), phba->CAregaddr); readl(phba->CAregaddr); /* flush */ } }