From mboxrd@z Thu Jan 1 00:00:00 1970 From: Sinan Kaya Subject: [PATCH v4 09/17] net: qla3xxx: Eliminate duplicate barriers on weakly-ordered archs Date: Mon, 19 Mar 2018 22:42:24 -0400 Message-ID: <1521513753-7325-10-git-send-email-okaya@codeaurora.org> References: <1521513753-7325-1-git-send-email-okaya@codeaurora.org> Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <1521513753-7325-1-git-send-email-okaya@codeaurora.org> Sender: linux-kernel-owner@vger.kernel.org To: netdev@vger.kernel.org, timur@codeaurora.org, sulrich@codeaurora.org Cc: linux-arm-msm@vger.kernel.org, linux-arm-kernel@lists.infradead.org, Sinan Kaya , Dept-GELinuxNICDev@cavium.com, linux-kernel@vger.kernel.org List-Id: linux-arm-msm@vger.kernel.org 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 --- drivers/net/ethernet/qlogic/qla3xxx.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/drivers/net/ethernet/qlogic/qla3xxx.c b/drivers/net/ethernet/qlogic/qla3xxx.c index 9e5264d..0e71b74 100644 --- a/drivers/net/ethernet/qlogic/qla3xxx.c +++ b/drivers/net/ethernet/qlogic/qla3xxx.c @@ -1858,8 +1858,8 @@ static void ql_update_small_bufq_prod_index(struct ql3_adapter *qdev) qdev->small_buf_release_cnt -= 8; } wmb(); - writel(qdev->small_buf_q_producer_index, - &port_regs->CommonRegs.rxSmallQProducerIndex); + writel_relaxed(qdev->small_buf_q_producer_index, + &port_regs->CommonRegs.rxSmallQProducerIndex); } } -- 2.7.4 From mboxrd@z Thu Jan 1 00:00:00 1970 From: okaya@codeaurora.org (Sinan Kaya) Date: Mon, 19 Mar 2018 22:42:24 -0400 Subject: [PATCH v4 09/17] net: qla3xxx: Eliminate duplicate barriers on weakly-ordered archs In-Reply-To: <1521513753-7325-1-git-send-email-okaya@codeaurora.org> References: <1521513753-7325-1-git-send-email-okaya@codeaurora.org> Message-ID: <1521513753-7325-10-git-send-email-okaya@codeaurora.org> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org 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 --- drivers/net/ethernet/qlogic/qla3xxx.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/drivers/net/ethernet/qlogic/qla3xxx.c b/drivers/net/ethernet/qlogic/qla3xxx.c index 9e5264d..0e71b74 100644 --- a/drivers/net/ethernet/qlogic/qla3xxx.c +++ b/drivers/net/ethernet/qlogic/qla3xxx.c @@ -1858,8 +1858,8 @@ static void ql_update_small_bufq_prod_index(struct ql3_adapter *qdev) qdev->small_buf_release_cnt -= 8; } wmb(); - writel(qdev->small_buf_q_producer_index, - &port_regs->CommonRegs.rxSmallQProducerIndex); + writel_relaxed(qdev->small_buf_q_producer_index, + &port_regs->CommonRegs.rxSmallQProducerIndex); } } -- 2.7.4