5.4-stable review patch. If anyone has any objections, please let me know.
------------------
From: Simon Horman <horms@xxxxxxxxxx>
[ 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 <andrew@xxxxxxx>
Signed-off-by: Simon Horman <horms@xxxxxxxxxx>
Link: https://lore.kernel.org/r/20240430-mv88e6xx-list_empty-v3-1-c35c69d88d2e@xxxxxxxxxx
Signed-off-by: Jakub Kicinski <kuba@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
drivers/net/dsa/mv88e6xxx/chip.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
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;
--
2.43.0
