Re: [RESEND PATCH] x86/sgx: Use vmalloc_array() instead of vmalloc()

Huang, Kai
2024-10-28T22:29:16Z

On 27/10/2024 12:32 am, Thorsten Blum wrote:
> Use vmalloc_array() instead of vmalloc() to calculate the number of
> bytes to allocate.

This says nothing about _why_. Is it because we want to take advantage
of the multiplication overflow check inside the vmalloc_array()?

I don't know whether it is implied we should always use vmalloc_array()
for array allocation like this, i.e., when we see vmalloc() is used for
array allocation in the kernel we can just write a patch to replace it
with vmalloc_array() and send to upstream.

I am fine with the code change, though. So if you can add one more
sentence to explain why (it's always good to do so), feel free to add:

Acked-by: Kai Huang <kai.huang@intel.com>

>
> Reviewed-by: Jarkko Sakkinen <jarkko@kernel.org>
> Signed-off-by: Thorsten Blum <thorsten.blum@linux.dev>
> ---
> arch/x86/kernel/cpu/sgx/main.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/arch/x86/kernel/cpu/sgx/main.c b/arch/x86/kernel/cpu/sgx/main.c
> index 9ace84486499..1a59e5956f4b 100644
> --- a/arch/x86/kernel/cpu/sgx/main.c
> +++ b/arch/x86/kernel/cpu/sgx/main.c
> @@ -630,7 +630,7 @@ static bool __init sgx_setup_epc_section(u64 phys_addr, u64 size,
> if (!section->virt_addr)
> return false;
>
> - section->pages = vmalloc(nr_pages * sizeof(struct sgx_epc_page));
> + section->pages = vmalloc_array(nr_pages, sizeof(struct sgx_epc_page));
> if (!section->pages) {
> memunmap(section->virt_addr);
> return false;