This is a note to let you know that I've just added the patch titled
net: lan78xx: fix runtime PM count underflow on link stop
to the 4.19-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
net-lan78xx-fix-runtime-pm-count-underflow-on-link-s.patch
and it can be found in the queue-4.19 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 5a186077bc2a0c4b6cc8f02bdfed968dc0342acd
Author: Oleksij Rempel <o.rempel@xxxxxxxxxxxxxx>
Date: Wed Feb 28 13:45:17 2024 +0100
net: lan78xx: fix runtime PM count underflow on link stop
[ Upstream commit 1eecc7ab82c42133b748e1895275942a054a7f67 ]
Current driver has some asymmetry in the runtime PM calls. On lan78xx_open()
it will call usb_autopm_get() and unconditionally usb_autopm_put(). And
on lan78xx_stop() it will call only usb_autopm_put(). So far, it was
working only because this driver do not activate autosuspend by default,
so it was visible only by warning "Runtime PM usage count underflow!".
Since, with current driver, we can't use runtime PM with active link,
execute lan78xx_open()->usb_autopm_put() only in error case. Otherwise,
keep ref counting high as long as interface is open.
Fixes: 55d7de9de6c3 ("Microchip's LAN7800 family USB 2/3 to 10/100/1000 Ethernet device driver")
Signed-off-by: Oleksij Rempel <o.rempel@xxxxxxxxxxxxxx>
Reviewed-by: Jiri Pirko <jiri@xxxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/drivers/net/usb/lan78xx.c b/drivers/net/usb/lan78xx.c
index 52d1d922f6c5e..f56f45c924de0 100644
--- a/drivers/net/usb/lan78xx.c
+++ b/drivers/net/usb/lan78xx.c
@@ -2940,7 +2940,8 @@ static int lan78xx_open(struct net_device *net)
done:
mutex_unlock(&dev->dev_mutex);
- usb_autopm_put_interface(dev->intf);
+ if (ret < 0)
+ usb_autopm_put_interface(dev->intf);
return ret;
}
