Re: [PATCH v2] video: fbdev: Fix Warning comparing pointer to 0 reported by coccicheck

On 6/3/19 1:57 PM, Mathieu Malaterre wrote:

On Mon, Jun 3, 2019 at 1:21 PM [off-list ref] wrote:

quoted

From: Shobhit Kukreti <redacted>

Fixed Warning Comparing Pointer to 0. Changed return value to -ENOMEM to
report kzalloc failure

drivers/video/fbdev/controlfb.c: WARNING comparing pointer to 0
drivers/video/fbdev/controlfb.c: WARNING comparing pointer to 0
drivers/video/fbdev/controlfb.c: WARNING comparing pointer to 0

Signed-off-by: Shobhit Kukreti <redacted>
---
Changes in v2:
 - Modified commit message to report change in return type

 drivers/video/fbdev/controlfb.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/drivers/video/fbdev/controlfb.c b/drivers/video/fbdev/controlfb.c
index 7af8db2..07907c5 100644
--- a/drivers/video/fbdev/controlfb.c
+++ b/drivers/video/fbdev/controlfb.c

@@ -182,7 +182,7 @@ int init_module(void)
        int ret = -ENXIO;

        dp = of_find_node_by_name(NULL, "control");
-       if (dp != 0 && !control_of_init(dp))
+       if (dp != NULL && !control_of_init(dp))
                ret = 0;
        of_node_put(dp);

@@ -580,7 +580,7 @@ static int __init control_init(void)
        control_setup(option);

        dp = of_find_node_by_name(NULL, "control");
-       if (dp != 0 && !control_of_init(dp))
+       if (dp != NULL && !control_of_init(dp))
                ret = 0;
        of_node_put(dp);

@@ -683,8 +683,8 @@ static int __init control_of_init(struct device_node *dp)
                return -ENXIO;
        }
        p = kzalloc(sizeof(*p), GFP_KERNEL);
-       if (p = 0)
-               return -ENXIO;
+       if (p = NULL)

nit: I would have use `!p` (same for the others above). Maybe
checkpatch with --strict would warn for those (can't remember from top
of my head).

Anyway:

Reviewed-by: Mathieu Malaterre <redacted>

quoted

+               return -ENOMEM;
        control_fb = p; /* save it for cleanups */

        /* Map in frame buffer and registers */

Patch queued (with some fixups, please see below) for v5.3, thanks.

Best regards,
--
Bartlomiej Zolnierkiewicz
Samsung R&D Institute Poland
Samsung Electronics


From: Shobhit Kukreti <redacted>
Subject: [PATCH] video: fbdev: controlfb: fix warnings about comparing pointer to 0

Fix warnings aboout comparing pointer to 0 reported by coccicheck:

drivers/video/fbdev/controlfb.c: WARNING comparing pointer to 0
drivers/video/fbdev/controlfb.c: WARNING comparing pointer to 0
drivers/video/fbdev/controlfb.c: WARNING comparing pointer to 0

Also while at it change return value to -ENOMEM on kzalloc() failure.

Signed-off-by: Shobhit Kukreti <redacted>
Reviewed-by: Mathieu Malaterre <redacted>
[b.zolnierkie: minor fixups]
Signed-off-by: Bartlomiej Zolnierkiewicz <redacted>
---
 drivers/video/fbdev/controlfb.c |    8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

Index: b/drivers/video/fbdev/controlfb.c
=================================--- a/drivers/video/fbdev/controlfb.c

+++ b/drivers/video/fbdev/controlfb.c

@@ -182,7 +182,7 @@ int init_module(void)
 	int ret = -ENXIO;
 
 	dp = of_find_node_by_name(NULL, "control");
-	if (dp != 0 && !control_of_init(dp))
+	if (dp && !control_of_init(dp))
 		ret = 0;
 	of_node_put(dp);
 

@@ -580,7 +580,7 @@ static int __init control_init(void)
 	control_setup(option);
 
 	dp = of_find_node_by_name(NULL, "control");
-	if (dp != 0 && !control_of_init(dp))
+	if (dp && !control_of_init(dp))
 		ret = 0;
 	of_node_put(dp);
 

@@ -683,8 +683,8 @@ static int __init control_of_init(struct
 		return -ENXIO;
 	}
 	p = kzalloc(sizeof(*p), GFP_KERNEL);
-	if (p = 0)
-		return -ENXIO;
+	if (!p)
+		return -ENOMEM;
 	control_fb = p;	/* save it for cleanups */
 
 	/* Map in frame buffer and registers */