From: Simon Horman Date: Tue, 30 Apr 2024 17:46:45 +0000 (+0100) Subject: net: dsa: mv88e6xxx: Correct check for empty list X-Git-Tag: v5.4.280~67 X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=3bf8d70e1455f87856640c3433b3660a31001618;p=thirdparty%2Fkernel%2Fstable.git net: dsa: mv88e6xxx: Correct check for empty list [ Upstream commit 4c7f3950a9fd53a62b156c0fe7c3a2c43b0ba19b ] Since commit a3c53be55c95 ("net: dsa: mv88e6xxx: Support multiple MDIO busses") mv88e6xxx_default_mdio_bus() has checked that the return value of list_first_entry() is non-NULL. This appears to be intended to guard against the list chip->mdios being empty. However, it is not the correct check as the implementation of list_first_entry is not designed to return NULL for empty lists. Instead, use list_first_entry_or_null() which does return NULL if the list is empty. Flagged by Smatch. Compile tested only. Reviewed-by: Andrew Lunn Signed-off-by: Simon Horman Link: https://lore.kernel.org/r/20240430-mv88e6xx-list_empty-v3-1-c35c69d88d2e@kernel.org Signed-off-by: Jakub Kicinski Signed-off-by: Sasha Levin --- diff --git a/drivers/net/dsa/mv88e6xxx/chip.c b/drivers/net/dsa/mv88e6xxx/chip.c index 81e6227cc8758..cf3d574374376 100644 --- a/drivers/net/dsa/mv88e6xxx/chip.c +++ b/drivers/net/dsa/mv88e6xxx/chip.c @@ -115,8 +115,8 @@ struct mii_bus *mv88e6xxx_default_mdio_bus(struct mv88e6xxx_chip *chip) { struct mv88e6xxx_mdio_bus *mdio_bus; - mdio_bus = list_first_entry(&chip->mdios, struct mv88e6xxx_mdio_bus, - list); + mdio_bus = list_first_entry_or_null(&chip->mdios, + struct mv88e6xxx_mdio_bus, list); if (!mdio_bus) return NULL;