| Message ID | 20190807161312.GA26835@embeddedor (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | video: fbdev/mmp/core: Use struct_size() in kzalloc() | expand |
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
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;
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(-)