[PATCH] usbnet: optimize barrier usage for Rmw atomic bitops

From: Davidlohr Bueso
Date: Wed Jan 29 2020 - 13:26:55 EST


Use smp_mb__before_atomic() instead of smp_mb() and avoid the
unnecessary barrier for non LL/SC architectures, such as x86.

Signed-off-by: Davidlohr Bueso <dbueso@xxxxxxx>
---
drivers/net/usb/usbnet.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/net/usb/usbnet.c b/drivers/net/usb/usbnet.c
index 5ec97def3513..24c767350e5e 100644
--- a/drivers/net/usb/usbnet.c
+++ b/drivers/net/usb/usbnet.c
@@ -1912,7 +1912,7 @@ int usbnet_resume (struct usb_interface *intf)
}
}

- smp_mb();
+ smp_mb__before_atomic();
clear_bit(EVENT_DEV_ASLEEP, &dev->flags);
spin_unlock_irq(&dev->txq.lock);

--
2.16.4