Guards inside tcp_prune_queue() are the same exactly.
But the patch adds the second point where out-of-order queue is discarded.
It is when the socket is under rcvbuf, but nevertheless skb cannot
be queued due to system-wide limit. In that case out-of-order queue
is dropped and the limits are rechecked.
Collapsing and tuning rcv_ssthresh was done once, they are not guarded
by rcvbuf check. So, repeating those steps would be useless.
The only thing is:
Formally, this is correct. But this is not necessary, pred_flags reset
is redundant even in the first place. The fast path is not so fast,
memory limit is checked explicitly there.
The patch is not perfect. F.e. tcp_prune_ofo_queue() could see empty
out-of-order queue, in this case the second sk_stream_rmem_schedule()
is useless and could be skipped. But it is the second order effect.
I think this will work.
--
