irq_find_mapping() returns a positive IRQ number or 0 if no IRQ is found
but it never returns a negative value. However, on each
irq_find_mapping() call, we verify that the returned value isn't
negative.

Fix the irq_find_mapping() checks to enter error paths when 0 is
returned. Return -EINVAL in such cases.

CC: stable@vger.kernel.org
Fixes: c9cd961c0d43 ("net: dsa: microchip: lan937x: add interrupt support for port phy link")
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: Bastien Curutchet (Schneider Electric) <bastien.curutchet@bootlin.com>
---
 drivers/net/dsa/microchip/ksz_common.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/drivers/net/dsa/microchip/ksz_common.c b/drivers/net/dsa/microchip/ksz_common.c
index 98cfb42b7257b8e3b4b5cce4bbf97def64537370..b17d29dda612ce00ce2e52fbe16c54bd6516c417 100644
--- a/drivers/net/dsa/microchip/ksz_common.c
+++ b/drivers/net/dsa/microchip/ksz_common.c
@@ -2585,8 +2585,8 @@ static int ksz_irq_phy_setup(struct ksz_device *dev)
 
 			irq = irq_find_mapping(dev->ports[port].pirq.domain,
 					       PORT_SRC_PHY_INT);
-			if (irq < 0) {
-				ret = irq;
+			if (!irq) {
+				ret = -EINVAL;
 				goto out;
 			}
 			ds->user_mii_bus->irq[phy] = irq;
@@ -2950,8 +2950,8 @@ static int ksz_pirq_setup(struct ksz_device *dev, u8 p)
 	snprintf(pirq->name, sizeof(pirq->name), "port_irq-%d", p);
 
 	pirq->irq_num = irq_find_mapping(dev->girq.domain, p);
-	if (pirq->irq_num < 0)
-		return pirq->irq_num;
+	if (!pirq->irq_num)
+		return -EINVAL;
 
 	return ksz_irq_common_setup(dev, pirq);
 }

-- 
2.51.1