Re: drm/amdkfd: Use memdup_user() rather than duplicating its

[Felix Kuehling <felix.kuehling@amd.com>]

On 2023-08-08 16:57, Atul Raut wrote:
> To prevent its redundant implementation and streamline
> code, use memdup_user.
>
> This fixes warnings reported by Coccinelle:
> ./drivers/gpu/drm/amd/amdkfd/kfd_device_queue_manager.c:2811:13-20: WARNING opportunity for memdup_user
>
> Signed-off-by: Atul Raut <rauji.raut@gmail.com>
> ---
>   drivers/gpu/drm/amd/amdkfd/kfd_device_queue_manager.c | 9 +++------
>   1 file changed, 3 insertions(+), 6 deletions(-)
>
> diff --git a/drivers/gpu/drm/amd/amdkfd/kfd_device_queue_manager.c b/drivers/gpu/drm/amd/amdkfd/kfd_device_queue_manager.c
> index 2df153828ff4..51740e007e89 100644
> --- a/drivers/gpu/drm/amd/amdkfd/kfd_device_queue_manager.c
> +++ b/drivers/gpu/drm/amd/amdkfd/kfd_device_queue_manager.c
> @@ -2808,12 +2808,9 @@ static uint32_t *get_queue_ids(uint32_t num_queues, uint32_t *usr_queue_id_array
>   	if (!usr_queue_id_array)
>   		return NULL;
>   
> -	queue_ids = kzalloc(array_size, GFP_KERNEL);
> -	if (!queue_ids)
> -		return ERR_PTR(-ENOMEM);
> -
> -	if (copy_from_user(queue_ids, usr_queue_id_array, array_size))
> -		return ERR_PTR(-EFAULT);
> +	queue_ids = memdup_user(usr_queue_id_array, array_size);
> +	if (IS_ERR(Iqueue_ids))

You have a typo in the variable name here. Did you at least compile-test 
the patch?


> +		return ERR_PTR(queue_ids);

I think it should just return queue_ids here. That's already an ERR_PTR 
in case of errors. So you don't even need the "if". Just this should do 
the job:

     return memdup_user(usr_queue_id_array, array_size);

The error checking is done by the caller.

Regards,
   Felix


>   
>   	return queue_ids;
>   }