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Tue, 20 Mar 2018 02:50:12 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=codeaurora.org; s=default; t=1521514214; bh=W9/yviHskqvwFPloVpoKaCcmJwlqdPqG2IWrksKoXY0=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=MWVSX6QlqGdyn8teHhBhixyiolrGKEn+lihL0C9Vlzc3GM3paJPA7NWhu9Ho+795O R25MyVO3K3GGDmb0T49NIddFbg58FN+CmUFrE5b0Gy8qkAaE5XoiwVgV57HNpSPmVV bHRCnddyeZRzJd1ItKyf7dB4lfBjWQqvBHcn0aMo= DMARC-Filter: OpenDMARC Filter v1.3.2 smtp.codeaurora.org 0165A60FEE 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 1/7] scsi: hpsa: Eliminate duplicate barriers on weakly-ordered archs Date: Mon, 19 Mar 2018 22:50:01 -0400 Message-Id: <1521514207-10695-2-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-20180320_025029_383930_728CF2DA X-CRM114-Status: GOOD ( 13.19 ) 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: Don Brace , "James E.J. Bottomley" , "Martin K. Petersen" , linux-arm-msm@vger.kernel.org, esc.storagedev@microsemi.com, linux-kernel@vger.kernel.org, Sinan Kaya , 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 wmb() 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 Acked-by: Don Brace Reviewed-by: Laurence Oberman --- drivers/scsi/hpsa.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/scsi/hpsa.h b/drivers/scsi/hpsa.h index 018f980..c7d7e6a 100644 --- a/drivers/scsi/hpsa.h +++ b/drivers/scsi/hpsa.h @@ -599,7 +599,7 @@ static unsigned long SA5_ioaccel_mode1_completed(struct ctlr_info *h, u8 q) * but with current driver design this is easiest. */ wmb(); - writel((q << 24) | rq->current_entry, h->vaddr + + writel_relaxed((q << 24) | rq->current_entry, h->vaddr + IOACCEL_MODE1_CONSUMER_INDEX); atomic_dec(&h->commands_outstanding); }