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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, Pavel Skripkin <paskripkin@gmail.com>,
        "David S. Miller" <davem@davemloft.net>,
        Sasha Levin <sashal@kernel.org>
Subject: [PATCH 5.4 219/348] net: ethernet: ezchip: fix error handling
Date:   Mon, 12 Jul 2021 08:10:03 +0200
Message-Id: <20210712060730.616623365@linuxfoundation.org>
In-Reply-To: <20210712060659.886176320@linuxfoundation.org>
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From: Pavel Skripkin <paskripkin@gmail.com>

[ 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@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 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 026a3ec19b6e..3d74401b4f10 100644
--- a/drivers/net/ethernet/ezchip/nps_enet.c
+++ b/drivers/net/ethernet/ezchip/nps_enet.c
@@ -610,7 +610,7 @@ 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;
-- 
2.30.2