On Mon, 13 Jul 2020 00:55:20 +0200 Richard Sailer wrote:
> This adds support for the SIOCOUTQ IOCTL to get the send buffer fill
> of a DCCP socket, like UDP and TCP sockets already have.
>
> Regarding the used data field: DCCP uses per packet sequence numbers,
> not per byte, so sequence numbers can't be used like in TCP. sk_wmem_queued
> is not used by DCCP and always 0, even in test on highly congested paths.
> Therefore this uses sk_wmem_alloc like in UDP.
>
> Signed-off-by: Richard Sailer <richard_siegfried@xxxxxxxxxxxx>
Sorry for the late review
> diff --git a/Documentation/networking/dccp.rst b/Documentation/networking/dccp.rst
> index dde16be044562..74659da107f6b 100644
> --- a/Documentation/networking/dccp.rst
> +++ b/Documentation/networking/dccp.rst
> @@ -192,6 +192,8 @@ FIONREAD
> Works as in udp(7): returns in the ``int`` argument pointer the size of
> the next pending datagram in bytes, or 0 when no datagram is pending.
>
> +SIOCOUTQ
> + Returns the number of data bytes in the local send queue.
FIONREAD uses tabs for indentation, it seems like a good idea to
document the size of the argument (i.e. "returns in the ``int`` ...").
> Other tunables
> ==============
> diff --git a/net/dccp/proto.c b/net/dccp/proto.c
> index c13b6609474b6..dab74e8a8a69b 100644
> --- a/net/dccp/proto.c
> +++ b/net/dccp/proto.c
> @@ -375,6 +375,14 @@ int dccp_ioctl(struct sock *sk, int cmd, unsigned long arg)
> goto out;
>
> switch (cmd) {
> + case SIOCOUTQ: {
> + /* Using sk_wmem_alloc here because sk_wmem_queued is not used by DCCP and
> + * always 0, comparably to UDP.
> + */
> + int amount = sk_wmem_alloc_get(sk);
> + rc = put_user(amount, (int __user *)arg);
checkpatch warns:
WARNING: Missing a blank line after declarations
#48: FILE: net/dccp/proto.c:383:
+ int amount = sk_wmem_alloc_get(sk);
+ rc = put_user(amount, (int __user *)arg);
Could you please address that, and better still move the declaration of
"int amount" up to the function level and avoid the funky bracket around
the case statement altogether?
> + }
> + break;
> case SIOCINQ: {
> struct sk_buff *skb;
> unsigned long amount = 0;
