Re: [PATCH] net: remove sock_iocb

[David Miller <davem@davemloft.net>]

From: Al Viro <viro@ZenIV.linux.org.uk>
Date: Thu, 29 Jan 2015 07:57:21 +0000

> You know, that's getting _really_ interesting.  The thing is, now
> there's only one ->sendmsg() instance using iocb argument at all,
> and it's a really weird one.  TIPC.  Which only compares it with
> NULL, and that - to tell the normal calls (== done by sock_sendmsg()
> et.al.) from tipc_{accept,connect}()-generated ones.  And the way
> it's used is
>         if (iocb)
>                 lock_sock(sk);
> in tipc_send_stream().  IOW, "tipc_accept() and tipc_connect() would like
> to use the guts of tipc_send_stream(), but they are already holding the
> socket locked; let's just pass NULL iocb (which net/socket.c never does)
> to tell it to leave the fucking lock alone, thank you very much".
> 
> And no ->recvmsg() are using iocb at all now.  How about we take the
> guts of tipc_send_stream() into a helper function and have tipc_accept/connect
> use _that_?  Then we could drop iocb argument completely and for ->sendmsg()
> it would be the difference between 4 and 3 arguments, which has interesting
> effects on certain register-starved architectures...
> 
> While we are at it, size (both for sendmsg and recvmsg) is always equal to
> iov_iter_count(&msg->msg_iter), so that's not the only redundant argument
> there...

No objections from me.