Re: [PATCH] amdkfd: use sizeof(long) granularity for the pasid bitmask

[Oded Gabbay]

On 12/03/2014 04:26 PM, Sasha Levin wrote:
> All the bit operations (such as find_first_zero_bit()) read sizeof(long) bytes
> at a time. If we allocated less than sizeof(long) bytes for the bitmask we
> would be accessing invalid memory when working with the bitmask.
>
> Change the allocator to allocate sizeof(long) multiples for the bitmask.
>
> Signed-off-by: Sasha Levin <sasha.levin@xxxxxxxxxx>
> ---
>   drivers/gpu/drm/amd/amdkfd/kfd_pasid.c | 3 +--
>   1 file changed, 1 insertion(+), 2 deletions(-)
>
> diff --git a/drivers/gpu/drm/amd/amdkfd/kfd_pasid.c b/drivers/gpu/drm/amd/amdkfd/kfd_pasid.c
> index 2458ab7..71699ad 100644
> --- a/drivers/gpu/drm/amd/amdkfd/kfd_pasid.c
> +++ b/drivers/gpu/drm/amd/amdkfd/kfd_pasid.c
> @@ -32,8 +32,7 @@ int kfd_pasid_init(void)
>   {
>   	pasid_limit = max_num_of_processes;
>
> -	pasid_bitmap = kzalloc(DIV_ROUND_UP(pasid_limit, BITS_PER_BYTE),
> -				GFP_KERNEL);
> +	pasid_bitmap = kzalloc(BITS_TO_LONGS(pasid_limit), GFP_KERNEL);
>   	if (!pasid_bitmap)
>   		return -ENOMEM;

Thanks!
Applied to my -next tree.

Oded
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