Re: [PATCH v4 mptcp-next 1/4] mptcp: never fetch fwd memory from the subflow

[Mat Martineau <mathew.j.martineau@linux.intel.com>]

On Tue, 21 Jun 2022, Paolo Abeni wrote:

> The memory accounting is broken in such exceptional code
> path, and after commit 4890b686f408 ("net: keep sk->sk_forward_alloc
> as small as possible") we can't find much help there.
>
> Drop the broken code.
>
> Signed-off-by: Paolo Abeni <pabeni@redhat.com>
> ---

Thanks Paolo, v4 looks good.

For patches 1-3:

Reviewed-by: Mat Martineau <mathew.j.martineau@linux.intel.com>

See patch 4 for different tag.


> This is possibly for net, but makes sense only on top of recent
> net-next patches, so whatever ;)

I agree it makes sense for net-next.

- Mat

> ---
> net/mptcp/protocol.c | 11 +++--------
> 1 file changed, 3 insertions(+), 8 deletions(-)
>
> diff --git a/net/mptcp/protocol.c b/net/mptcp/protocol.c
> index 6d2aa41390e7..0d4b2c010da0 100644
> --- a/net/mptcp/protocol.c
> +++ b/net/mptcp/protocol.c
> @@ -328,15 +328,10 @@ static bool mptcp_rmem_schedule(struct sock *sk, struct sock *ssk, int size)
>
> 	amt = sk_mem_pages(size);
> 	amount = amt << PAGE_SHIFT;
> -	msk->rmem_fwd_alloc += amount;
> -	if (!__sk_mem_raise_allocated(sk, size, amt, SK_MEM_RECV)) {
> -		if (ssk->sk_forward_alloc < amount) {
> -			msk->rmem_fwd_alloc -= amount;
> -			return false;
> -		}
> +	if (!__sk_mem_raise_allocated(sk, size, amt, SK_MEM_RECV))
> +		return false;
>
> -		ssk->sk_forward_alloc -= amount;
> -	}
> +	msk->rmem_fwd_alloc += amount;
> 	return true;
> }
>
> -- 
> 2.35.3
>
>
>

--
Mat Martineau
Intel