From 1eecc7ab82c42133b748e1895275942a054a7f67 Mon Sep 17 00:00:00 2001
From: Oleksij Rempel <o.rempel@pengutronix.de>
Date: Wed, 28 Feb 2024 13:45:17 +0100
Subject: [PATCH] net: lan78xx: fix runtime PM count underflow on link stop
Git-commit: 1eecc7ab82c42133b748e1895275942a054a7f67
References: git-fixes
Patch-mainline: v6.8
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@pengutronix.de>
Reviewed-by: Jiri Pirko <jiri@nvidia.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Oliver Neukum <oneukum@suse.com>
---
drivers/net/usb/lan78xx.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
--- a/drivers/net/usb/lan78xx.c
+++ b/drivers/net/usb/lan78xx.c
@@ -2370,7 +2370,8 @@ static int lan78xx_change_mtu(struct net
}
}
- usb_autopm_put_interface(dev->intf);
+ if (ret < 0)
+ usb_autopm_put_interface(dev->intf);
return 0;
}