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From: Sinan Kaya <okaya@codeaurora.org>
To: netdev@vger.kernel.org, timur@codeaurora.org, sulrich@codeaurora.org
Cc: linux-arm-msm@vger.kernel.org, linux-kernel@vger.kernel.org,
	Sinan Kaya <okaya@codeaurora.org>,
	Ariel Elior <ariel.elior@cavium.com>,
	everest-linux-l2@cavium.com,
	linux-arm-kernel@lists.infradead.org
Subject: [PATCH v6 3/6] bnx2x: Replace doorbell barrier() with wmb()
Date: Fri, 23 Mar 2018 18:23:08 -0400	[thread overview]
Message-ID: <1521843791-21201-4-git-send-email-okaya@codeaurora.org> (raw)
In-Reply-To: <1521843791-21201-1-git-send-email-okaya@codeaurora.org>

barrier() doesn't guarantee memory writes to be observed by the hardware on
all architectures. barrier() only tells compiler not to move this code
with respect to other read/writes.

If memory write needs to be observed by the HW, wmb() is the right choice.

Signed-off-by: Sinan Kaya <okaya@codeaurora.org>
---
 drivers/net/ethernet/broadcom/bnx2x/bnx2x_cmn.c     | 3 ++-
 drivers/net/ethernet/broadcom/bnx2x/bnx2x_ethtool.c | 3 ++-
 2 files changed, 4 insertions(+), 2 deletions(-)

diff --git a/drivers/net/ethernet/broadcom/bnx2x/bnx2x_cmn.c b/drivers/net/ethernet/broadcom/bnx2x/bnx2x_cmn.c
index d7c98e8..b97820f 100644
--- a/drivers/net/ethernet/broadcom/bnx2x/bnx2x_cmn.c
+++ b/drivers/net/ethernet/broadcom/bnx2x/bnx2x_cmn.c
@@ -4153,7 +4153,8 @@ netdev_tx_t bnx2x_start_xmit(struct sk_buff *skb, struct net_device *dev)
 	wmb();
 
 	txdata->tx_db.data.prod += nbd;
-	barrier();
+	/* make sur edescriptor update is observed by HW */
+	wmb();
 
 	DOORBELL(bp, txdata->cid, txdata->tx_db.raw);
 
diff --git a/drivers/net/ethernet/broadcom/bnx2x/bnx2x_ethtool.c b/drivers/net/ethernet/broadcom/bnx2x/bnx2x_ethtool.c
index 1e33abd..39af4f8 100644
--- a/drivers/net/ethernet/broadcom/bnx2x/bnx2x_ethtool.c
+++ b/drivers/net/ethernet/broadcom/bnx2x/bnx2x_ethtool.c
@@ -2591,7 +2591,8 @@ static int bnx2x_run_loopback(struct bnx2x *bp, int loopback_mode)
 	wmb();
 
 	txdata->tx_db.data.prod += 2;
-	barrier();
+	/* make sure descriptor update is observed by the HW */
+	wmb();
 	DOORBELL(bp, txdata->cid, txdata->tx_db.raw);
 
 	mmiowb();
-- 
2.7.4

WARNING: multiple messages have this Message-ID (diff)
From: Sinan Kaya <okaya@codeaurora.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 <okaya@codeaurora.org>,
	Ariel Elior <ariel.elior@cavium.com>,
	everest-linux-l2@cavium.com, linux-kernel@vger.kernel.org
Subject: [PATCH v6 3/6] bnx2x: Replace doorbell barrier() with wmb()
Date: Fri, 23 Mar 2018 18:23:08 -0400	[thread overview]
Message-ID: <1521843791-21201-4-git-send-email-okaya@codeaurora.org> (raw)
In-Reply-To: <1521843791-21201-1-git-send-email-okaya@codeaurora.org>

barrier() doesn't guarantee memory writes to be observed by the hardware on
all architectures. barrier() only tells compiler not to move this code
with respect to other read/writes.

If memory write needs to be observed by the HW, wmb() is the right choice.

Signed-off-by: Sinan Kaya <okaya@codeaurora.org>
---
 drivers/net/ethernet/broadcom/bnx2x/bnx2x_cmn.c     | 3 ++-
 drivers/net/ethernet/broadcom/bnx2x/bnx2x_ethtool.c | 3 ++-
 2 files changed, 4 insertions(+), 2 deletions(-)

diff --git a/drivers/net/ethernet/broadcom/bnx2x/bnx2x_cmn.c b/drivers/net/ethernet/broadcom/bnx2x/bnx2x_cmn.c
index d7c98e8..b97820f 100644
--- a/drivers/net/ethernet/broadcom/bnx2x/bnx2x_cmn.c
+++ b/drivers/net/ethernet/broadcom/bnx2x/bnx2x_cmn.c
@@ -4153,7 +4153,8 @@ netdev_tx_t bnx2x_start_xmit(struct sk_buff *skb, struct net_device *dev)
 	wmb();
 
 	txdata->tx_db.data.prod += nbd;
-	barrier();
+	/* make sur edescriptor update is observed by HW */
+	wmb();
 
 	DOORBELL(bp, txdata->cid, txdata->tx_db.raw);
 
diff --git a/drivers/net/ethernet/broadcom/bnx2x/bnx2x_ethtool.c b/drivers/net/ethernet/broadcom/bnx2x/bnx2x_ethtool.c
index 1e33abd..39af4f8 100644
--- a/drivers/net/ethernet/broadcom/bnx2x/bnx2x_ethtool.c
+++ b/drivers/net/ethernet/broadcom/bnx2x/bnx2x_ethtool.c
@@ -2591,7 +2591,8 @@ static int bnx2x_run_loopback(struct bnx2x *bp, int loopback_mode)
 	wmb();
 
 	txdata->tx_db.data.prod += 2;
-	barrier();
+	/* make sure descriptor update is observed by the HW */
+	wmb();
 	DOORBELL(bp, txdata->cid, txdata->tx_db.raw);
 
 	mmiowb();
-- 
2.7.4

WARNING: multiple messages have this Message-ID (diff)
From: okaya@codeaurora.org (Sinan Kaya)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH v6 3/6] bnx2x: Replace doorbell barrier() with wmb()
Date: Fri, 23 Mar 2018 18:23:08 -0400	[thread overview]
Message-ID: <1521843791-21201-4-git-send-email-okaya@codeaurora.org> (raw)
In-Reply-To: <1521843791-21201-1-git-send-email-okaya@codeaurora.org>

barrier() doesn't guarantee memory writes to be observed by the hardware on
all architectures. barrier() only tells compiler not to move this code
with respect to other read/writes.

If memory write needs to be observed by the HW, wmb() is the right choice.

Signed-off-by: Sinan Kaya <okaya@codeaurora.org>
---
 drivers/net/ethernet/broadcom/bnx2x/bnx2x_cmn.c     | 3 ++-
 drivers/net/ethernet/broadcom/bnx2x/bnx2x_ethtool.c | 3 ++-
 2 files changed, 4 insertions(+), 2 deletions(-)

diff --git a/drivers/net/ethernet/broadcom/bnx2x/bnx2x_cmn.c b/drivers/net/ethernet/broadcom/bnx2x/bnx2x_cmn.c
index d7c98e8..b97820f 100644
--- a/drivers/net/ethernet/broadcom/bnx2x/bnx2x_cmn.c
+++ b/drivers/net/ethernet/broadcom/bnx2x/bnx2x_cmn.c
@@ -4153,7 +4153,8 @@ netdev_tx_t bnx2x_start_xmit(struct sk_buff *skb, struct net_device *dev)
 	wmb();
 
 	txdata->tx_db.data.prod += nbd;
-	barrier();
+	/* make sur edescriptor update is observed by HW */
+	wmb();
 
 	DOORBELL(bp, txdata->cid, txdata->tx_db.raw);
 
diff --git a/drivers/net/ethernet/broadcom/bnx2x/bnx2x_ethtool.c b/drivers/net/ethernet/broadcom/bnx2x/bnx2x_ethtool.c
index 1e33abd..39af4f8 100644
--- a/drivers/net/ethernet/broadcom/bnx2x/bnx2x_ethtool.c
+++ b/drivers/net/ethernet/broadcom/bnx2x/bnx2x_ethtool.c
@@ -2591,7 +2591,8 @@ static int bnx2x_run_loopback(struct bnx2x *bp, int loopback_mode)
 	wmb();
 
 	txdata->tx_db.data.prod += 2;
-	barrier();
+	/* make sure descriptor update is observed by the HW */
+	wmb();
 	DOORBELL(bp, txdata->cid, txdata->tx_db.raw);
 
 	mmiowb();
-- 
2.7.4

  parent reply	other threads:[~2018-03-23 22:23 UTC|newest]

Thread overview: 20+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-03-23 22:23 [PATCH v6 0/6] netdev: Eliminate duplicate barriers on weakly-ordered archs Sinan Kaya
2018-03-23 22:23 ` Sinan Kaya
2018-03-23 22:23 ` [PATCH v6 1/6] net: qla3xxx: " Sinan Kaya
2018-03-23 22:23   ` Sinan Kaya
2018-03-23 22:23 ` [PATCH v6 2/6] qlcnic: " Sinan Kaya
2018-03-23 22:23   ` Sinan Kaya
2018-03-23 22:23   ` Sinan Kaya
2018-03-23 22:23 ` Sinan Kaya [this message]
2018-03-23 22:23   ` [PATCH v6 3/6] bnx2x: Replace doorbell barrier() with wmb() Sinan Kaya
2018-03-23 22:23   ` Sinan Kaya
2018-03-23 22:23 ` [PATCH v6 4/6] bnx2x: Eliminate duplicate barriers on weakly-ordered archs Sinan Kaya
2018-03-23 22:23   ` Sinan Kaya
2018-03-23 22:23 ` [PATCH v6 5/6] net: qlge: " Sinan Kaya
2018-03-23 22:23   ` Sinan Kaya
2018-03-23 22:23 ` [PATCH v6 6/6] bnxt_en: " Sinan Kaya
2018-03-23 22:23   ` Sinan Kaya
2018-03-23 22:36   ` Michael Chan
2018-03-23 22:36     ` Michael Chan
2018-03-24  4:02     ` Sinan Kaya
2018-03-24  4:02       ` Sinan Kaya

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