Re: [PATCH 1/6] mm: add kmalloc_array_node and kcalloc_node

From: Vlastimil Babka
Date: Fri Sep 29 2017 - 08:00:44 EST


On 09/27/2017 10:20 AM, Johannes Thumshirn wrote:
> We have kmalloc_array() and kcalloc() wrappers on top of kmalloc() which
> ensure us overflow free multiplication for the size of a memory
> allocation but these implementations are not NUMA-aware.
>
> Likewise we have kmalloc_node() which is a NUMA-aware version of
> kmalloc() but the implementation is not aware of any possible overflows in
> eventual size calculations.
>
> Introduce a combination of the two above cases to have a NUMA-node aware
> version of kmalloc_array() and kcalloc().
>
> Signed-off-by: Johannes Thumshirn <jthumshirn@xxxxxxx>

Sounds better than custom open-coded stuff indeed.

Acked-by: Vlastimil Babka <vbabka@xxxxxxx>

> ---
> include/linux/slab.h | 16 ++++++++++++++++
> 1 file changed, 16 insertions(+)
>
> diff --git a/include/linux/slab.h b/include/linux/slab.h
> index 41473df6dfb0..aaf4723e41b3 100644
> --- a/include/linux/slab.h
> +++ b/include/linux/slab.h
> @@ -635,6 +635,22 @@ extern void *__kmalloc_track_caller(size_t, gfp_t, unsigned long);
> #define kmalloc_track_caller(size, flags) \
> __kmalloc_track_caller(size, flags, _RET_IP_)
>
> +static inline void *kmalloc_array_node(size_t n, size_t size, gfp_t flags,
> + int node)
> +{
> + if (size != 0 && n > SIZE_MAX / size)
> + return NULL;
> + if (__builtin_constant_p(n) && __builtin_constant_p(size))
> + return kmalloc_node(n * size, flags, node);
> + return __kmalloc_node(n * size, flags, node);
> +}
> +
> +static inline void *kcalloc_node(size_t n, size_t size, gfp_t flags, int node)
> +{
> + return kmalloc_array_node(n, size, flags | __GFP_ZERO, node);
> +}
> +
> +
> #ifdef CONFIG_NUMA
> extern void *__kmalloc_node_track_caller(size_t, gfp_t, int, unsigned long);
> #define kmalloc_node_track_caller(size, flags, node) \
>