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Thu, 22 Mar 2018 16:30:49 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=codeaurora.org; s=default; t=1521736250; bh=hGb4O2x7FjRLDgQ7Cd8PA8ZloLdYMumBeD2pzirvYaQ=; h=From:To:Cc:Subject:Date:From; b=ahGqnluY71YSmK5NfFKqiQGVC2inhD+LBUXXufbGPawn/ZKMzNBkqfut32CgpGKG+ S04zGotqqIYgCifb7i4S5eAyZgpB0GTG0SaYGDuIg6bpIg9Ev1LJ9hNk2MN7w/w0TE P52UVWVqCpNLZTbtlrarBi2uMn20U7hBQct5ve8E= DMARC-Filter: OpenDMARC Filter v1.3.2 smtp.codeaurora.org 264A060131 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-rdma@vger.kernel.org, timur@codeaurora.org, sulrich@codeaurora.org Subject: [PATCH v6] RDMA/qedr: eliminate duplicate barriers on weakly-ordered archs #2 Date: Thu, 22 Mar 2018 12:30:44 -0400 Message-Id: <1521736245-23662-1-git-send-email-okaya@codeaurora.org> X-Mailer: git-send-email 2.7.4 MIME-Version: 1.0 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20180322_093100_984540_38319179 X-CRM114-Status: GOOD ( 11.86 ) 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: linux-arm-msm@vger.kernel.org, Doug Ledford , Michal Kalderon , linux-kernel@vger.kernel.org, Sinan Kaya , Jason Gunthorpe , Ariel Elior , 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() in multiple places. 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/infiniband/hw/qedr/verbs.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/drivers/infiniband/hw/qedr/verbs.c b/drivers/infiniband/hw/qedr/verbs.c index 53f00db..d1cf9a0 100644 --- a/drivers/infiniband/hw/qedr/verbs.c +++ b/drivers/infiniband/hw/qedr/verbs.c @@ -35,6 +35,7 @@ #include #include #include +#include #include #include @@ -860,7 +861,7 @@ static void doorbell_cq(struct qedr_cq *cq, u32 cons, u8 flags) wmb(); cq->db.data.agg_flags = flags; cq->db.data.value = cpu_to_le32(cons); - writeq(cq->db.raw, cq->db_addr); + writeq_relaxed(cq->db.raw, cq->db_addr); /* Make sure write would stick */ mmiowb(); @@ -3338,7 +3339,7 @@ int qedr_post_recv(struct ib_qp *ibqp, struct ib_recv_wr *wr, qp->rq.db_data.data.value++; - writel(qp->rq.db_data.raw, qp->rq.db); + writel_relaxed(qp->rq.db_data.raw, qp->rq.db); /* Make sure write sticks */ mmiowb();