2019-05-24 17:17:32

by Gustavo A. R. Silva

[permalink] [raw]
Subject: [PATCH] drm/nouveau/mmu: use struct_size() helper

Make use of the struct_size() helper instead of an open-coded version
in order to avoid any potential type mistakes, in particular in the
context in which this code is being used.

So, replace the following form:

sizeof(*kind) + sizeof(*kind->data) * mmu->kind_nr;

with:

struct_size(kind, data, mmu->kind_nr)

This code was detected with the help of Coccinelle.

Signed-off-by: Gustavo A. R. Silva <[email protected]>
---
drivers/gpu/drm/nouveau/nvif/mmu.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/nouveau/nvif/mmu.c b/drivers/gpu/drm/nouveau/nvif/mmu.c
index ae08a1ca8044..5641bda2046d 100644
--- a/drivers/gpu/drm/nouveau/nvif/mmu.c
+++ b/drivers/gpu/drm/nouveau/nvif/mmu.c
@@ -110,7 +110,7 @@ nvif_mmu_init(struct nvif_object *parent, s32 oclass, struct nvif_mmu *mmu)

if (mmu->kind_nr) {
struct nvif_mmu_kind_v0 *kind;
- u32 argc = sizeof(*kind) + sizeof(*kind->data) * mmu->kind_nr;
+ size_t argc = struct_size(kind, data, mmu->kind_nr);

if (ret = -ENOMEM, !(kind = kmalloc(argc, GFP_KERNEL)))
goto done;
--
2.21.0


2019-05-27 06:23:52

by Ben Skeggs

[permalink] [raw]
Subject: Re: [Nouveau] [PATCH] drm/nouveau/mmu: use struct_size() helper

On Sat, 25 May 2019 at 03:35, Gustavo A. R. Silva
<[email protected]> wrote:
>
> Make use of the struct_size() helper instead of an open-coded version
> in order to avoid any potential type mistakes, in particular in the
> context in which this code is being used.
>
> So, replace the following form:
>
> sizeof(*kind) + sizeof(*kind->data) * mmu->kind_nr;
>
> with:
>
> struct_size(kind, data, mmu->kind_nr)
>
> This code was detected with the help of Coccinelle.
>
> Signed-off-by: Gustavo A. R. Silva <[email protected]>
Thanks!

> ---
> drivers/gpu/drm/nouveau/nvif/mmu.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/gpu/drm/nouveau/nvif/mmu.c b/drivers/gpu/drm/nouveau/nvif/mmu.c
> index ae08a1ca8044..5641bda2046d 100644
> --- a/drivers/gpu/drm/nouveau/nvif/mmu.c
> +++ b/drivers/gpu/drm/nouveau/nvif/mmu.c
> @@ -110,7 +110,7 @@ nvif_mmu_init(struct nvif_object *parent, s32 oclass, struct nvif_mmu *mmu)
>
> if (mmu->kind_nr) {
> struct nvif_mmu_kind_v0 *kind;
> - u32 argc = sizeof(*kind) + sizeof(*kind->data) * mmu->kind_nr;
> + size_t argc = struct_size(kind, data, mmu->kind_nr);
>
> if (ret = -ENOMEM, !(kind = kmalloc(argc, GFP_KERNEL)))
> goto done;
> --
> 2.21.0
>
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