Merge branch 'rxrpc-miscellaneous-fixes'

David Howells says:

====================
rxrpc: Miscellaneous fixes (part)

Here some miscellaneous fixes for AF_RXRPC:

 (1) Fix the congestion control algorithm to start cwnd at 4 and to not cut
     ssthresh when the peer cuts its rwind size.

 (2) Only transmit a single ACK for all the DATA packets glued together
     into a jumbo packet to reduce the number of ACKs being generated.
====================

Link: https://lore.kernel.org/r/20240503150749.1001323-1-dhowells@redhat.com


Signed-off-by: Jakub Kicinski <kuba@kernel.org>