* [PATCH] video: fbdev/mmp/core: Use struct_size() in kzalloc()
@ 2019-08-07 16:13 ` Gustavo A. R. Silva
0 siblings, 0 replies; 4+ messages in thread
From: Gustavo A. R. Silva @ 2019-08-07 16:13 UTC (permalink / raw)
To: Bartlomiej Zolnierkiewicz
Cc: dri-devel, linux-fbdev, linux-kernel, Gustavo A. R. Silva
One of the more common cases of allocation size calculations is finding
the size of a structure that has a zero-sized array at the end, along
with memory for some number of elements for that array. For example:
struct mmp_path {
...
struct mmp_overlay overlays[0];
};
size = sizeof(struct mmp_path) + count * sizeof(struct mmp_overlay);
instance = kzalloc(size, GFP_KERNEL)
Instead of leaving these open-coded and prone to type mistakes, we can
now use the new struct_size() helper:
instance = kzalloc(struct_size(instance, overlays, count), GFP_KERNEL)
Notice that, in this case, variable size is not necessary, hence it
is removed.
This code was detected with the help of Coccinelle.
Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
---
drivers/video/fbdev/mmp/core.c | 6 ++----
1 file changed, 2 insertions(+), 4 deletions(-)
diff --git a/drivers/video/fbdev/mmp/core.c b/drivers/video/fbdev/mmp/core.c
index 0ffc1b7b7052..154127256a2c 100644
--- a/drivers/video/fbdev/mmp/core.c
+++ b/drivers/video/fbdev/mmp/core.c
@@ -153,13 +153,11 @@ EXPORT_SYMBOL_GPL(mmp_get_path);
struct mmp_path *mmp_register_path(struct mmp_path_info *info)
{
int i;
- size_t size;
struct mmp_path *path = NULL;
struct mmp_panel *panel;
- size = sizeof(struct mmp_path)
- + sizeof(struct mmp_overlay) * info->overlay_num;
- path = kzalloc(size, GFP_KERNEL);
+ path = kzalloc(struct_size(path, overlays, info->overlay_num),
+ GFP_KERNEL);
if (!path)
return NULL;
--
2.22.0
^ permalink raw reply related [flat|nested] 4+ messages in thread
* [PATCH] video: fbdev/mmp/core: Use struct_size() in kzalloc()
@ 2019-08-07 16:13 ` Gustavo A. R. Silva
0 siblings, 0 replies; 4+ messages in thread
From: Gustavo A. R. Silva @ 2019-08-07 16:13 UTC (permalink / raw)
To: Bartlomiej Zolnierkiewicz
Cc: dri-devel, linux-fbdev, linux-kernel, Gustavo A. R. Silva
One of the more common cases of allocation size calculations is finding
the size of a structure that has a zero-sized array at the end, along
with memory for some number of elements for that array. For example:
struct mmp_path {
...
struct mmp_overlay overlays[0];
};
size = sizeof(struct mmp_path) + count * sizeof(struct mmp_overlay);
instance = kzalloc(size, GFP_KERNEL)
Instead of leaving these open-coded and prone to type mistakes, we can
now use the new struct_size() helper:
instance = kzalloc(struct_size(instance, overlays, count), GFP_KERNEL)
Notice that, in this case, variable size is not necessary, hence it
is removed.
This code was detected with the help of Coccinelle.
Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
---
drivers/video/fbdev/mmp/core.c | 6 ++----
1 file changed, 2 insertions(+), 4 deletions(-)
diff --git a/drivers/video/fbdev/mmp/core.c b/drivers/video/fbdev/mmp/core.c
index 0ffc1b7b7052..154127256a2c 100644
--- a/drivers/video/fbdev/mmp/core.c
+++ b/drivers/video/fbdev/mmp/core.c
@@ -153,13 +153,11 @@ EXPORT_SYMBOL_GPL(mmp_get_path);
struct mmp_path *mmp_register_path(struct mmp_path_info *info)
{
int i;
- size_t size;
struct mmp_path *path = NULL;
struct mmp_panel *panel;
- size = sizeof(struct mmp_path)
- + sizeof(struct mmp_overlay) * info->overlay_num;
- path = kzalloc(size, GFP_KERNEL);
+ path = kzalloc(struct_size(path, overlays, info->overlay_num),
+ GFP_KERNEL);
if (!path)
return NULL;
--
2.22.0
^ permalink raw reply related [flat|nested] 4+ messages in thread
* Re: [PATCH] video: fbdev/mmp/core: Use struct_size() in kzalloc()
2019-08-07 16:13 ` Gustavo A. R. Silva
@ 2019-08-19 14:10 ` Bartlomiej Zolnierkiewicz
-1 siblings, 0 replies; 4+ messages in thread
From: Bartlomiej Zolnierkiewicz @ 2019-08-19 14:10 UTC (permalink / raw)
To: Gustavo A. R. Silva; +Cc: dri-devel, linux-fbdev, linux-kernel
On 8/7/19 6:13 PM, Gustavo A. R. Silva wrote:
> One of the more common cases of allocation size calculations is finding
> the size of a structure that has a zero-sized array at the end, along
> with memory for some number of elements for that array. For example:
>
> struct mmp_path {
> ...
> struct mmp_overlay overlays[0];
> };
>
> size = sizeof(struct mmp_path) + count * sizeof(struct mmp_overlay);
> instance = kzalloc(size, GFP_KERNEL)
>
> Instead of leaving these open-coded and prone to type mistakes, we can
> now use the new struct_size() helper:
>
> instance = kzalloc(struct_size(instance, overlays, count), GFP_KERNEL)
>
> Notice that, in this case, variable size is not necessary, hence it
> is removed.
>
> This code was detected with the help of Coccinelle.
>
> Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
Patch queued for v5.4, thanks.
Best regards,
--
Bartlomiej Zolnierkiewicz
Samsung R&D Institute Poland
Samsung Electronics
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH] video: fbdev/mmp/core: Use struct_size() in kzalloc()
@ 2019-08-19 14:10 ` Bartlomiej Zolnierkiewicz
0 siblings, 0 replies; 4+ messages in thread
From: Bartlomiej Zolnierkiewicz @ 2019-08-19 14:10 UTC (permalink / raw)
To: Gustavo A. R. Silva; +Cc: dri-devel, linux-fbdev, linux-kernel
On 8/7/19 6:13 PM, Gustavo A. R. Silva wrote:
> One of the more common cases of allocation size calculations is finding
> the size of a structure that has a zero-sized array at the end, along
> with memory for some number of elements for that array. For example:
>
> struct mmp_path {
> ...
> struct mmp_overlay overlays[0];
> };
>
> size = sizeof(struct mmp_path) + count * sizeof(struct mmp_overlay);
> instance = kzalloc(size, GFP_KERNEL)
>
> Instead of leaving these open-coded and prone to type mistakes, we can
> now use the new struct_size() helper:
>
> instance = kzalloc(struct_size(instance, overlays, count), GFP_KERNEL)
>
> Notice that, in this case, variable size is not necessary, hence it
> is removed.
>
> This code was detected with the help of Coccinelle.
>
> Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
Patch queued for v5.4, thanks.
Best regards,
--
Bartlomiej Zolnierkiewicz
Samsung R&D Institute Poland
Samsung Electronics
^ permalink raw reply [flat|nested] 4+ messages in thread
end of thread, other threads:[~2019-08-19 14:10 UTC | newest]
Thread overview: 4+ messages (download: mbox.gz / follow: Atom feed)
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2019-08-07 16:13 ` [PATCH] video: fbdev/mmp/core: Use struct_size() in kzalloc() Gustavo A. R. Silva
2019-08-07 16:13 ` Gustavo A. R. Silva
2019-08-19 14:10 ` Bartlomiej Zolnierkiewicz
2019-08-19 14:10 ` Bartlomiej Zolnierkiewicz
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