mptcp: fill skb extension cache outside of mptcp_sendmsg_frag

The mptcp_sendmsg_frag helper contains a loop that will wait on the
subflow sk.

It seems preferrable to only wait in mptcp_sendmsg() when blocking io is
requested.  mptcp_sendmsg already has such a wait loop that is used when
no subflow socket is available for transmission.

This is a preparation patch that makes sure we call
mptcp_sendmsg_frag only if a skb extension has been allocated.

Moreover, such allocation currently uses GFP_ATOMIC while it
could use sleeping allocation instead.

Followup patches will remove the wait loop from mptcp_sendmsg_frag()
and will allow to do a sleeping allocation for the extension.

Acked-by: Paolo Abeni <[email protected]>
Signed-off-by: Florian Westphal <[email protected]>
Signed-off-by: David S. Miller <[email protected]>

0 files changed, 0 insertions, 0 deletions