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SubjectRe: [PATCH 1/3] mm: vmalloc: introduce array allocation functions
On Tue 08-03-22 05:59:16, Paolo Bonzini wrote:
> Linux has dozens of occurrences of vmalloc(array_size()) and
> vzalloc(array_size()). Allow to simplify the code by providing
> vmalloc_array and vcalloc, as well as the underscored variants that let
> the caller specify the GFP flags.
>
> Cc: stable@vger.kernel.org
> Cc: linux-mm@kvack.org
> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

Seems useful
Acked-by: Michal Hocko <mhocko@suse.com>

Is there any reason you haven't used __alloc_size(1, 2) annotation?

Thanks!
> ---
> include/linux/vmalloc.h | 5 +++++
> mm/util.c | 50 +++++++++++++++++++++++++++++++++++++++++
> 2 files changed, 55 insertions(+)
>
> diff --git a/include/linux/vmalloc.h b/include/linux/vmalloc.h
> index 880227b9f044..d1bbd4fd50c5 100644
> --- a/include/linux/vmalloc.h
> +++ b/include/linux/vmalloc.h
> @@ -159,6 +159,11 @@ void *__vmalloc_node(unsigned long size, unsigned long align, gfp_t gfp_mask,
> int node, const void *caller) __alloc_size(1);
> void *vmalloc_no_huge(unsigned long size) __alloc_size(1);
>
> +extern void *__vmalloc_array(size_t n, size_t size, gfp_t flags) __alloc_size(1, 2);
> +extern void *vmalloc_array(size_t n, size_t size) __alloc_size(1, 2);
> +extern void *__vcalloc(size_t n, size_t size, gfp_t flags) __alloc_size(1, 2);
> +extern void *vcalloc(size_t n, size_t size) __alloc_size(1, 2);
> +
> extern void vfree(const void *addr);
> extern void vfree_atomic(const void *addr);
>
> diff --git a/mm/util.c b/mm/util.c
> index 7e43369064c8..94475abe54a0 100644
> --- a/mm/util.c
> +++ b/mm/util.c
> @@ -647,6 +647,56 @@ void *kvrealloc(const void *p, size_t oldsize, size_t newsize, gfp_t flags)
> }
> EXPORT_SYMBOL(kvrealloc);
>
> +/**
> + * __vmalloc_array - allocate memory for a virtually contiguous array.
> + * @n: number of elements.
> + * @size: element size.
> + * @flags: the type of memory to allocate (see kmalloc).
> + */
> +void *__vmalloc_array(size_t n, size_t size, gfp_t flags)
> +{
> + size_t bytes;
> +
> + if (unlikely(check_mul_overflow(n, size, &bytes)))
> + return NULL;
> + return __vmalloc(bytes, flags);
> +}
> +EXPORT_SYMBOL(__vmalloc_array);
> +
> +/**
> + * vmalloc_array - allocate memory for a virtually contiguous array.
> + * @n: number of elements.
> + * @size: element size.
> + */
> +void *vmalloc_array(size_t n, size_t size)
> +{
> + return __vmalloc_array(n, size, GFP_KERNEL);
> +}
> +EXPORT_SYMBOL(vmalloc_array);
> +
> +/**
> + * __vcalloc - allocate and zero memory for a virtually contiguous array.
> + * @n: number of elements.
> + * @size: element size.
> + * @flags: the type of memory to allocate (see kmalloc).
> + */
> +void *__vcalloc(size_t n, size_t size, gfp_t flags)
> +{
> + return __vmalloc_array(n, size, flags | __GFP_ZERO);
> +}
> +EXPORT_SYMBOL(__vcalloc);
> +
> +/**
> + * vcalloc - allocate and zero memory for a virtually contiguous array.
> + * @n: number of elements.
> + * @size: element size.
> + */
> +void *vcalloc(size_t n, size_t size)
> +{
> + return __vmalloc_array(n, size, GFP_KERNEL | __GFP_ZERO);
> +}
> +EXPORT_SYMBOL(vcalloc);
> +
> /* Neutral page->mapping pointer to address_space or anon_vma or other */
> void *page_rmapping(struct page *page)
> {
> --
> 2.31.1

--
Michal Hocko
SUSE Labs

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