[PATCH] net: systemport: Fix ordering in intrl2_*_mask_clear macro

[PATCH] net: systemport: Fix ordering in intrl2_*_mask_clear macro

[Florian Fainelli]

Since we keep shadow copies of which interrupt sources are enabled
through the intrl2_*_mask_{set,clear} macros, make sure that the
ordering in which we do these two operations: update the copy, then
unmask the register is correct.

This is not currently a problem because we actually do not use them, but
we will in a subsequent patch optimizing register accesses, so better be
safe here.

Fixes: 80105befdb4b ("net: systemport: add Broadcom SYSTEMPORT Ethernet MAC driver")
Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
---
David,

This is intentionally targetting the "net-next" tree since it is
not yet a problem, yet this is still technically a bugfix. No need
to backport this to -stable or anything.

Thanks!

 drivers/net/ethernet/broadcom/bcmsysport.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/net/ethernet/broadcom/bcmsysport.c b/drivers/net/ethernet/broadcom/bcmsysport.c
index b2d30863caeb..2059911014db 100644
--- a/drivers/net/ethernet/broadcom/bcmsysport.c
+++ b/drivers/net/ethernet/broadcom/bcmsysport.c
@@ -58,8 +58,8 @@ BCM_SYSPORT_IO_MACRO(topctrl, SYS_PORT_TOPCTRL_OFFSET);
 static inline void intrl2_##which##_mask_clear(struct bcm_sysport_priv *priv, \
 						u32 mask)		\
 {									\
-	intrl2_##which##_writel(priv, mask, INTRL2_CPU_MASK_CLEAR);	\
 	priv->irq##which##_mask &= ~(mask);				\
+	intrl2_##which##_writel(priv, mask, INTRL2_CPU_MASK_CLEAR);	\
 }									\
 static inline void intrl2_##which##_mask_set(struct bcm_sysport_priv *priv, \
 						u32 mask)		\
-- 
2.7.4

Re: [PATCH] net: systemport: Fix ordering in intrl2_*_mask_clear macro

[David Miller]

From: Florian Fainelli <f.fainelli@gmail.com>
Date: Wed, 24 Aug 2016 14:21:41 -0700

> Since we keep shadow copies of which interrupt sources are enabled
> through the intrl2_*_mask_{set,clear} macros, make sure that the
> ordering in which we do these two operations: update the copy, then
> unmask the register is correct.
> 
> This is not currently a problem because we actually do not use them, but
> we will in a subsequent patch optimizing register accesses, so better be
> safe here.
> 
> Fixes: 80105befdb4b ("net: systemport: add Broadcom SYSTEMPORT Ethernet MAC driver")
> Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
> ---
> David,
> 
> This is intentionally targetting the "net-next" tree since it is
> not yet a problem, yet this is still technically a bugfix. No need
> to backport this to -stable or anything.

Fair enough, applied to net-next.

Thanks!