[PATCH 4.14 109/315] net: ethernet: ezchip: fix error handling

From: Greg Kroah-Hartman
Date: Mon Jul 19 2021 - 11:39:20 EST

From: Pavel Skripkin <paskripkin@xxxxxxxxx>

[ Upstream commit 0de449d599594f5472e00267d651615c7f2c6c1d ]

As documented at drivers/base/platform.c for platform_get_irq:

* Gets an IRQ for a platform device and prints an error message if finding the
* IRQ fails. Device drivers should check the return value for errors so as to
* not pass a negative integer value to the request_irq() APIs.

So, the driver should check that platform_get_irq() return value
is _negative_, not that it's equal to zero, because -ENXIO (return
value from request_irq() if irq was not found) will
pass this check and it leads to passing negative irq to request_irq()

Fixes: 0dd077093636 ("NET: Add ezchip ethernet driver")
Signed-off-by: Pavel Skripkin <paskripkin@xxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
drivers/net/ethernet/ezchip/nps_enet.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/net/ethernet/ezchip/nps_enet.c b/drivers/net/ethernet/ezchip/nps_enet.c
index fbadf08b7c5d..70ccbd11b9e7 100644
--- a/drivers/net/ethernet/ezchip/nps_enet.c
+++ b/drivers/net/ethernet/ezchip/nps_enet.c
@@ -623,7 +623,7 @@ static s32 nps_enet_probe(struct platform_device *pdev)

/* Get IRQ number */
priv->irq = platform_get_irq(pdev, 0);
- if (!priv->irq) {
+ if (priv->irq < 0) {
dev_err(dev, "failed to retrieve <irq Rx-Tx> value from device tree\n");
err = -ENODEV;
goto out_netdev;