RE: [PATCH v3 11/18] qlcnic: Eliminate duplicate barriers on weakly-ordered archs

[Chopra, Manish]

> -Original Message-
> From: Sinan Kaya [mailto:ok...@codeaurora.org]
> Sent: Friday, March 16, 2018 9:46 PM
> To: net...@vger.kernel.org; ti...@codeaurora.org; sulr...@codeaurora.org
> Cc: linux-arm-...@vger.kernel.org; linux-arm-ker...@lists.infradead.org;
> Sinan Kaya <ok...@codeaurora.org>; Patil, Harish <harish.pa...@cavium.com>;
> Chopra, Manish <manish.cho...@cavium.com>; Dept-GE Linux NIC Dev  gelinuxnic...@cavium.com>; linux-kernel@vger.kernel.org
> Subject: [PATCH v3 11/18] qlcnic: Eliminate duplicate barriers on 
> weakly-ordered
> archs
> 
> 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 <ok...@codeaurora.org>
> ---
>  drivers/net/ethernet/qlogic/qlcnic/qlcnic_83xx_hw.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/net/ethernet/qlogic/qlcnic/qlcnic_83xx_hw.c
> b/drivers/net/ethernet/qlogic/qlcnic/qlcnic_83xx_hw.c
> index 46b0372..97c146e7 100644
> --- a/drivers/net/ethernet/qlogic/qlcnic/qlcnic_83xx_hw.c
> +++ b/drivers/net/ethernet/qlogic/qlcnic/qlcnic_83xx_hw.c
> @@ -478,7 +478,7 @@ irqreturn_t qlcnic_83xx_clear_legacy_intr(struct
> qlcnic_adapter *adapter)
>   wmb();
> 
>   /* clear the interrupt trigger control register */
> - writel(0, adapter->isr_int_vec);
> + writel_relaxed(0, adapter->isr_int_vec);
>   intr_val = readl(adapter->isr_int_vec);
>   do {
>   intr_val = readl(adapter->tgt_status_reg);
> --
> 2.7.4

Acked-by: Manish Chopra <manish.cho...@cavium.com>

Thanks.

RE: [PATCH v3 11/18] qlcnic: Eliminate duplicate barriers on weakly-ordered archs

[Chopra, Manish]

> -Original Message-
> From: Sinan Kaya [mailto:ok...@codeaurora.org]
> Sent: Friday, March 16, 2018 9:46 PM
> To: net...@vger.kernel.org; ti...@codeaurora.org; sulr...@codeaurora.org
> Cc: linux-arm-...@vger.kernel.org; linux-arm-ker...@lists.infradead.org;
> Sinan Kaya ; Patil, Harish ;
> Chopra, Manish ; Dept-GE Linux NIC Dev  gelinuxnic...@cavium.com>; linux-kernel@vger.kernel.org
> Subject: [PATCH v3 11/18] qlcnic: Eliminate duplicate barriers on 
> weakly-ordered
> archs
> 
> 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/qlcnic/qlcnic_83xx_hw.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/net/ethernet/qlogic/qlcnic/qlcnic_83xx_hw.c
> b/drivers/net/ethernet/qlogic/qlcnic/qlcnic_83xx_hw.c
> index 46b0372..97c146e7 100644
> --- a/drivers/net/ethernet/qlogic/qlcnic/qlcnic_83xx_hw.c
> +++ b/drivers/net/ethernet/qlogic/qlcnic/qlcnic_83xx_hw.c
> @@ -478,7 +478,7 @@ irqreturn_t qlcnic_83xx_clear_legacy_intr(struct
> qlcnic_adapter *adapter)
>   wmb();
> 
>   /* clear the interrupt trigger control register */
> - writel(0, adapter->isr_int_vec);
> + writel_relaxed(0, adapter->isr_int_vec);
>   intr_val = readl(adapter->isr_int_vec);
>   do {
>   intr_val = readl(adapter->tgt_status_reg);
> --
> 2.7.4

Acked-by: Manish Chopra 

Thanks.

[PATCH v3 11/18] qlcnic: Eliminate duplicate barriers on weakly-ordered archs

[Sinan Kaya]

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/qlcnic/qlcnic_83xx_hw.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/net/ethernet/qlogic/qlcnic/qlcnic_83xx_hw.c 
b/drivers/net/ethernet/qlogic/qlcnic/qlcnic_83xx_hw.c
index 46b0372..97c146e7 100644
--- a/drivers/net/ethernet/qlogic/qlcnic/qlcnic_83xx_hw.c
+++ b/drivers/net/ethernet/qlogic/qlcnic/qlcnic_83xx_hw.c
@@ -478,7 +478,7 @@ irqreturn_t qlcnic_83xx_clear_legacy_intr(struct 
qlcnic_adapter *adapter)
wmb();
 
/* clear the interrupt trigger control register */
-   writel(0, adapter->isr_int_vec);
+   writel_relaxed(0, adapter->isr_int_vec);
intr_val = readl(adapter->isr_int_vec);
do {
intr_val = readl(adapter->tgt_status_reg);
-- 
2.7.4

[PATCH v3 11/18] qlcnic: Eliminate duplicate barriers on weakly-ordered archs

[Sinan Kaya]

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/qlcnic/qlcnic_83xx_hw.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/net/ethernet/qlogic/qlcnic/qlcnic_83xx_hw.c 
b/drivers/net/ethernet/qlogic/qlcnic/qlcnic_83xx_hw.c
index 46b0372..97c146e7 100644
--- a/drivers/net/ethernet/qlogic/qlcnic/qlcnic_83xx_hw.c
+++ b/drivers/net/ethernet/qlogic/qlcnic/qlcnic_83xx_hw.c
@@ -478,7 +478,7 @@ irqreturn_t qlcnic_83xx_clear_legacy_intr(struct 
qlcnic_adapter *adapter)
wmb();
 
/* clear the interrupt trigger control register */
-   writel(0, adapter->isr_int_vec);
+   writel_relaxed(0, adapter->isr_int_vec);
intr_val = readl(adapter->isr_int_vec);
do {
intr_val = readl(adapter->tgt_status_reg);
-- 
2.7.4