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[v4,08/17] drivers: net: cxgb: Eliminate duplicate barriers on weakly-ordered archs

Message ID 1521513753-7325-9-git-send-email-okaya@codeaurora.org (mailing list archive)
State New, archived
Headers show

Commit Message

Sinan Kaya March 20, 2018, 2:42 a.m. UTC 
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 <okaya@codeaurora.org>
---
 drivers/net/ethernet/chelsio/cxgb/sge.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
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Patch

diff --git a/drivers/net/ethernet/chelsio/cxgb/sge.c b/drivers/net/ethernet/chelsio/cxgb/sge.c
index 30de26e..57891bd6 100644
--- a/drivers/net/ethernet/chelsio/cxgb/sge.c
+++ b/drivers/net/ethernet/chelsio/cxgb/sge.c
@@ -495,7 +495,7 @@  static struct sk_buff *sched_skb(struct sge *sge, struct sk_buff *skb,
 static inline void doorbell_pio(struct adapter *adapter, u32 val)
 {
 	wmb();
-	writel(val, adapter->regs + A_SG_DOORBELL);
+	writel_relaxed(val, adapter->regs + A_SG_DOORBELL);
 }
 
 /*