Re: [RFC PATCH v2 04/48] net: Declare MSG_SPLICE_PAGES internal sendmsg() flag

[Willem de Bruijn]

David Howells wrote:
> Willem de Bruijn <willemdebruijn.kernel@xxxxxxxxx> wrote:
> 
> > No need to modify __sys_sendmmsg explicitly, as it ends up calling
> > __sys_sendmsg?
> > 
> > Also, sendpage does this flags masking in the internal sock_FUNC
> > helpers rather than __sys_FUNC. Might be preferable.
> 
> I was wondering whether other flags, such as MSG_BATCH should be added to the
> list.  Is it bad if userspace sets that in sendmsg()?  AF_KCM, at least, looks
> at it.

That flag was added exactly for AF_KCM. A process that explicitly
sets it might experience bad behavior (increased latency), but
there are no legacy AF_KCM applications that precede the flag.