net: dsa: microchip: ptp: Fix checks on irq_find_mapping()

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

Fix the irq_find_mapping() check to enter the error path when 0 is
returned. Return -EINVAL in such case.

Cc: stable@vger.kernel.org
Fixes: cc13ab18b201 ("net: dsa: microchip: ptp: enable interrupt for timestamping")
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: Bastien Curutchet (Schneider Electric) <bastien.curutchet@bootlin.com>
Link: https://patch.msgid.link/20251120-ksz-fix-v6-2-891f80ae7f8f@bootlin.com
Signed-off-by: Paolo Abeni <pabeni@redhat.com>

diff --git a/drivers/net/dsa/microchip/ksz_ptp.c b/drivers/net/dsa/microchip/ksz_ptp.c
index 35fc21b1ee48a47daa278573bfe8749c7b42c731..c8bfbe5e2157323ecf29149d1907b77e689aa221 100644 (file)
--- a/drivers/net/dsa/microchip/ksz_ptp.c
+++ b/drivers/net/dsa/microchip/ksz_ptp.c
@@ -1139,8 +1139,8 @@ int ksz_ptp_irq_setup(struct dsa_switch *ds, u8 p)
                irq_create_mapping(ptpirq->domain, irq);
 
        ptpirq->irq_num = irq_find_mapping(port->pirq.domain, PORT_SRC_PTP_INT);
-       if (ptpirq->irq_num < 0) {
-               ret = ptpirq->irq_num;
+       if (!ptpirq->irq_num) {
+               ret = -EINVAL;
                goto out;
        }