net: ll_temac: Fix potential NULL dereference in temac_probe()

platform_get_resource() may fail and in this case a NULL dereference
will occur.

Fix it to use devm_platform_ioremap_resource() instead of calling
platform_get_resource() and devm_ioremap().

This is detected by Coccinelle semantic patch.

@@
expression pdev, res, n, t, e, e1, e2;
@@

res = \(platform_get_resource\|platform_get_resource_byname\)(pdev, t, n);
+ if (!res)
+   return -EINVAL;
... when != res == NULL
e = devm_ioremap(e1, res->start, e2);

Fixes: 8425c41d1ef7 ("net: ll_temac: Extend support to non-device-tree platforms")
Signed-off-by: Zhang Changzhong <zhangchangzhong@huawei.com>
Acked-by: Esben Haabendal <esben@geanix.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/drivers/net/ethernet/xilinx/ll_temac_main.c b/drivers/net/ethernet/xilinx/ll_temac_main.c
index 60c199fcb91e5b2938b73a98696f46db8f76acf9..030185301014c3e36a4762ea9b7666b6f03b9e4c 100644 (file)
--- a/drivers/net/ethernet/xilinx/ll_temac_main.c
+++ b/drivers/net/ethernet/xilinx/ll_temac_main.c
@@ -1351,7 +1351,6 @@ static int temac_probe(struct platform_device *pdev)
        struct device_node *temac_np = dev_of_node(&pdev->dev), *dma_np;
        struct temac_local *lp;
        struct net_device *ndev;
-       struct resource *res;
        const void *addr;
        __be32 *p;
        bool little_endian;
@@ -1500,13 +1499,11 @@ static int temac_probe(struct platform_device *pdev)
                of_node_put(dma_np);
        } else if (pdata) {
                /* 2nd memory resource specifies DMA registers */
-               res = platform_get_resource(pdev, IORESOURCE_MEM, 1);
-               lp->sdma_regs = devm_ioremap(&pdev->dev, res->start,
-                                                    resource_size(res));
-               if (!lp->sdma_regs) {
+               lp->sdma_regs = devm_platform_ioremap_resource(pdev, 1);
+               if (IS_ERR(lp->sdma_regs)) {
                        dev_err(&pdev->dev,
                                "could not map DMA registers\n");
-                       return -ENOMEM;
+                       return PTR_ERR(lp->sdma_regs);
                }
                if (pdata->dma_little_endian) {
                        lp->dma_in = temac_dma_in32_le;