From patchwork Tue Mar 20 02:50:07 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Sinan Kaya X-Patchwork-Id: 10296097 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 82749602C2 for ; Tue, 20 Mar 2018 02:51:05 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 7418628E94 for ; Tue, 20 Mar 2018 02:51:05 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 684EE28F5F; Tue, 20 Mar 2018 02:51:05 +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 EB14D28E94 for ; Tue, 20 Mar 2018 02:51:04 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752354AbeCTCun (ORCPT ); Mon, 19 Mar 2018 22:50:43 -0400 Received: from smtp.codeaurora.org ([198.145.29.96]:35940 "EHLO smtp.codeaurora.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752230AbeCTCuh (ORCPT ); Mon, 19 Mar 2018 22:50:37 -0400 Received: by smtp.codeaurora.org (Postfix, from userid 1000) id AFAE260F91; Tue, 20 Mar 2018 02:50:30 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=codeaurora.org; s=default; t=1521514234; bh=5iEz6F+cE53acOy9eJzhM5s93Skgi312BeMzer4uRzg=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=EIteVMHoF3fx3zricEdUEPo5C2xQVPM/HHtA98Jiwn4pTj0thIrcLQFt1fbG0CNv5 WoGMRBZ4EAkl7eKIfLBWxoW7oaB/iho4Yi+AVnxpD+2QUZJY5a7zkbX+UjHn8HWs8g sTqA77nSFWCS5J8T1wbxqdQ+sGSxRgHx5gvOorQg= 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 647D560F92; Tue, 20 Mar 2018 02:50:27 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=codeaurora.org; s=default; t=1521514228; bh=5iEz6F+cE53acOy9eJzhM5s93Skgi312BeMzer4uRzg=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=PGph8JNP0o5i+RcabxDYn0PgJ7QEBrMg/5bEyXGSZdf/XFXr+vfUcvkv40zBKJYJw UBz470ZVSnt8gKokWP73tXQdrtYAiRNxsNicWI5BgCklY3t164Wq9nkAHhHY3HSrhC aDaRLSljcMeUyuhxErmxqblKHo9fOhRr1SGm5qpE= DMARC-Filter: OpenDMARC Filter v1.3.2 smtp.codeaurora.org 647D560F92 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 E.J. Bottomley" , "Martin K. Petersen" , Varun Prakash , Peter Senna Tschudin , Romain Perier , linux-kernel@vger.kernel.org Subject: [PATCH v4 7/7] scsi: csiostor: Eliminate duplicate barriers on weakly-ordered archs Date: Mon, 19 Mar 2018 22:50:07 -0400 Message-Id: <1521514207-10695-8-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. Create a new wrapper function with relaxed write operator. Use the new wrapper when a write is following a barrier(). Signed-off-by: Sinan Kaya --- drivers/scsi/csiostor/csio_hw.h | 4 ++++ drivers/scsi/csiostor/csio_wr.c | 2 +- 2 files changed, 5 insertions(+), 1 deletion(-) diff --git a/drivers/scsi/csiostor/csio_hw.h b/drivers/scsi/csiostor/csio_hw.h index 30f5f52..9fd8b00 100644 --- a/drivers/scsi/csiostor/csio_hw.h +++ b/drivers/scsi/csiostor/csio_hw.h @@ -512,6 +512,10 @@ struct csio_hw { csio_reg((_h)->regstart, (_r))) #define csio_wr_reg16(_h, _v, _r) writew((_v), \ csio_reg((_h)->regstart, (_r))) + +#define csio_wr_reg32_relaxed(_h, _v, _r) \ + writel_relaxed((_v), csio_reg((_h)->regstart, (_r))) + #define csio_wr_reg32(_h, _v, _r) writel((_v), \ csio_reg((_h)->regstart, (_r))) #define csio_wr_reg64(_h, _v, _r) writeq((_v), \ diff --git a/drivers/scsi/csiostor/csio_wr.c b/drivers/scsi/csiostor/csio_wr.c index c0a1778..db26222 100644 --- a/drivers/scsi/csiostor/csio_wr.c +++ b/drivers/scsi/csiostor/csio_wr.c @@ -984,7 +984,7 @@ csio_wr_issue(struct csio_hw *hw, int qidx, bool prio) wmb(); /* Ring SGE Doorbell writing q->pidx into it */ - csio_wr_reg32(hw, DBPRIO_V(prio) | QID_V(q->un.eq.physeqid) | + csio_wr_reg32_relaxed(hw, DBPRIO_V(prio) | QID_V(q->un.eq.physeqid) | PIDX_T5_V(q->inc_idx) | DBTYPE_F, MYPF_REG(SGE_PF_KDOORBELL_A)); q->inc_idx = 0;