[PATCH net-next v15 11/14] net: add SO_DEVMEM_DONTNEED setsockopt to release RX frags

[David Ahern]

On 6/27/24 6:32 PM, Mina Almasry wrote:
> @@ -1049,6 +1050,62 @@ static int sock_reserve_memory(struct sock *sk, int bytes)
>  	return 0;
>  }
>  
> +#ifdef CONFIG_PAGE_POOL
> +static noinline_for_stack int
> +sock_devmem_dontneed(struct sock *sk, sockptr_t optval, unsigned int optlen)
> +{
> +	unsigned int num_tokens, i, j, k, netmem_num = 0;
> +	struct dmabuf_token *tokens;
> +	netmem_ref netmems[16];
> +	int ret = 0;
> +
> +	if (sk->sk_type != SOCK_STREAM || sk->sk_protocol != IPPROTO_TCP)
> +		return -EBADF;
> +
> +	if (optlen % sizeof(struct dmabuf_token) ||
> +	    optlen > sizeof(*tokens) * 128)
> +		return -EINVAL;
> +
> +	tokens = kvmalloc_array(128, sizeof(*tokens), GFP_KERNEL);

The '128' should be a named macro with a comment on why that value.