* [PATCH] powerpc/spufs: use struct_size() in kmalloc()
@ 2019-01-08 18:37 Gustavo A. R. Silva
2019-01-24 3:40 ` Michael Ellerman
0 siblings, 1 reply; 2+ messages in thread
From: Gustavo A. R. Silva @ 2019-01-08 18:37 UTC (permalink / raw)
To: Jeremy Kerr, Arnd Bergmann, Benjamin Herrenschmidt,
Paul Mackerras, Michael Ellerman
Cc: linuxppc-dev, 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 foo {
int stuff;
void *entry[];
};
instance = kmalloc(sizeof(struct foo) + sizeof(void *) * count, GFP_KERNEL);
Instead of leaving these open-coded and prone to type mistakes, we can
now use the new struct_size() helper:
instance = kmalloc(struct_size(instance, entry, count), GFP_KERNEL);
This code was detected with the help of Coccinelle.
Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
---
arch/powerpc/platforms/cell/spufs/file.c | 5 ++---
1 file changed, 2 insertions(+), 3 deletions(-)
diff --git a/arch/powerpc/platforms/cell/spufs/file.c b/arch/powerpc/platforms/cell/spufs/file.c
index ae8123edddc6..48c2477e7e2a 100644
--- a/arch/powerpc/platforms/cell/spufs/file.c
+++ b/arch/powerpc/platforms/cell/spufs/file.c
@@ -2338,9 +2338,8 @@ static int spufs_switch_log_open(struct inode *inode, struct file *file)
goto out;
}
- ctx->switch_log = kmalloc(sizeof(struct switch_log) +
- SWITCH_LOG_BUFSIZE * sizeof(struct switch_log_entry),
- GFP_KERNEL);
+ ctx->switch_log = kmalloc(struct_size(ctx->switch_log, log,
+ SWITCH_LOG_BUFSIZE), GFP_KERNEL);
if (!ctx->switch_log) {
rc = -ENOMEM;
--
2.20.1
^ permalink raw reply related [flat|nested] 2+ messages in thread
* Re: powerpc/spufs: use struct_size() in kmalloc()
2019-01-08 18:37 [PATCH] powerpc/spufs: use struct_size() in kmalloc() Gustavo A. R. Silva
@ 2019-01-24 3:40 ` Michael Ellerman
0 siblings, 0 replies; 2+ messages in thread
From: Michael Ellerman @ 2019-01-24 3:40 UTC (permalink / raw)
To: Gustavo A. R. Silva, Jeremy Kerr, Arnd Bergmann,
Benjamin Herrenschmidt, Paul Mackerras
Cc: linuxppc-dev, linux-kernel, Gustavo A. R. Silva
On Tue, 2019-01-08 at 18:37:20 UTC, "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 foo {
> int stuff;
> void *entry[];
> };
>
> instance = kmalloc(sizeof(struct foo) + sizeof(void *) * count, GFP_KERNEL);
>
> Instead of leaving these open-coded and prone to type mistakes, we can
> now use the new struct_size() helper:
>
> instance = kmalloc(struct_size(instance, entry, count), GFP_KERNEL);
>
> This code was detected with the help of Coccinelle.
>
> Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
Applied to powerpc next, thanks.
https://git.kernel.org/powerpc/c/00def7130af8b3fad1bdef98429c94a6
cheers
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