Re: [PATCH net-next] libceph: Partially revert changes to support MSG_SPLICE_PAGES

[Ilya Dryomov]

On Mon, Jun 26, 2023 at 10:44 PM David Howells <dhowells@xxxxxxxxxx> wrote:
>
> Ilya Dryomov <idryomov@xxxxxxxxx> wrote:
>
> >   if (sendpage_ok(bv.bv_page))
> >           msg.msg_flags |= MSG_SPLICE_PAGES;
> >   else
> >           msg.msg_flags &= ~MSG_SPLICE_PAGES;
>
> Hmmm...  I'm not sure there's any guarantee that msg, including msg_flags,
> won't get altered by ->sendmsg().

If this is indeed an issue, do_sendmsg() should be fixed too.  I would
like to avoid having do_try_sendpage() do one thing and do_sendmsg() do
something subtly different.

But then, even with the current patch, only msg_flags is reinitialized
on the next loop iteration, not the entire message.  Should the entire
message be reinitialized?

Thanks,

                Ilya