[PATCH] soc/fsl/qe: fix err handling of ucc_of_parse_tdm

[Yi Wang]

From: Wen Yang <wen.yan...@zte.com.cn>

Currently there are 2 problems with the ucc_of_parse_tdm function:
1,a possible null pointer dereference in ucc_of_parse_tdm,
detected by the semantic patch deref_null.cocci,
with the following warning:
drivers/soc/fsl/qe/qe_tdm.c:177:21-24: ERROR: pdev is NULL but dereferenced.
2,dev gets modified, so in any case that devm_iounmap() will fail even when
the new pdev is valid, because the iomap was done with a different pdev.
This patch fixes them.

Suggested-by: Christophe LEROY <christophe.le...@c-s.fr>
Signed-off-by: Wen Yang <wen.yan...@zte.com.cn>
CC: Julia Lawall <julia.law...@lip6.fr>
CC: Zhao Qiang <qiang.z...@nxp.com>
---
 drivers/soc/fsl/qe/qe_tdm.c | 20 ++++++++++----------
 1 file changed, 10 insertions(+), 10 deletions(-)

diff --git a/drivers/soc/fsl/qe/qe_tdm.c b/drivers/soc/fsl/qe/qe_tdm.c
index f78c346..9a29f0b 100644
--- a/drivers/soc/fsl/qe/qe_tdm.c
+++ b/drivers/soc/fsl/qe/qe_tdm.c
@@ -47,7 +47,7 @@ int ucc_of_parse_tdm(struct device_node *np, struct ucc_tdm 
*utdm,
        struct resource *res;
        struct device_node *np2;
        static int siram_init_flag;
-       struct platform_device *pdev;
+       struct platform_device *pdev_si, *pdev_siram;
 
        sprop = of_get_property(np, "fsl,rx-sync-clock", NULL);
        if (sprop) {
@@ -129,16 +129,16 @@ int ucc_of_parse_tdm(struct device_node *np, struct 
ucc_tdm *utdm,
        if (!np2)
                return -EINVAL;
 
-       pdev = of_find_device_by_node(np2);
-       if (!pdev) {
+       pdev_si = of_find_device_by_node(np2);
+       if (!pdev_si) {
                pr_err("%pOFn: failed to lookup pdev\n", np2);
                of_node_put(np2);
                return -EINVAL;
        }
 
        of_node_put(np2);
-       res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
-       utdm->si_regs = devm_ioremap_resource(&pdev->dev, res);
+       res = platform_get_resource(pdev_si, IORESOURCE_MEM, 0);
+       utdm->si_regs = devm_ioremap_resource(&pdev_si->dev, res);
        if (IS_ERR(utdm->si_regs)) {
                ret = PTR_ERR(utdm->si_regs);
                goto err_miss_siram_property;
@@ -150,8 +150,8 @@ int ucc_of_parse_tdm(struct device_node *np, struct ucc_tdm 
*utdm,
                goto err_miss_siram_property;
        }
 
-       pdev = of_find_device_by_node(np2);
-       if (!pdev) {
+       pdev_siram = of_find_device_by_node(np2);
+       if (!pdev_siram) {
                ret = -EINVAL;
                pr_err("%pOFn: failed to lookup pdev\n", np2);
                of_node_put(np2);
@@ -159,8 +159,8 @@ int ucc_of_parse_tdm(struct device_node *np, struct ucc_tdm 
*utdm,
        }
 
        of_node_put(np2);
-       res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
-       utdm->siram = devm_ioremap_resource(&pdev->dev, res);
+       res = platform_get_resource(pdev_siram, IORESOURCE_MEM, 0);
+       utdm->siram = devm_ioremap_resource(&pdev_siram->dev, res);
        if (IS_ERR(utdm->siram)) {
                ret = PTR_ERR(utdm->siram);
                goto err_miss_siram_property;
@@ -174,7 +174,7 @@ int ucc_of_parse_tdm(struct device_node *np, struct ucc_tdm 
*utdm,
        return ret;
 
 err_miss_siram_property:
-       devm_iounmap(&pdev->dev, utdm->si_regs);
+       devm_iounmap(&pdev_si->dev, utdm->si_regs);
        return ret;
 }
 EXPORT_SYMBOL(ucc_of_parse_tdm);
-- 
2.9.5