net/mlx5e: Sync TIR params updates against concurrent create/modify
Transport Interface Receive (TIR) objects perform the packet processing and
reassembly and is also responsible for demultiplexing the packets into the
different RQs.
There are certain TIR context attributes that propagate to the pointed RQs
and applied to them (like packet_merge offloads (LRO/SHAMPO) and
tunneled_offload_en). When TIRs do not agree on attributes values, a "last
one wins" policy is applied. Hence, if not synced properly, a race between
TIR params update and a concurrent TIR create/modify operation might yield
to a mismatch between the shadow parameters in SW and the actual applied
state of the RQs in HW.
tunneled_offload_en is a fixed attribute per profile, while packet merge
offload state might be toggled and get out-of-sync. When this happens,
packet_merge offload might be working although not requested, or the
opposite.
All updates to packet_merge state and all create/modify operations of
regular redirection/steering TIRs are done under the same priv->state_lock,
so they do not run in parallel, and no race is possible.
However, there are other kind of TIRs (acceleration offloads TIRs, like TLS
TIRs) which are created on demand for each new connection without holding
the coarse priv->state_lock, hence might race.
Fix this by synchronizing all packet_merge state reads and writes against
all TIR create/modify operations. Include the modify operations of the
regular redirection steering TIRs under the new lock, for better code
layering and division of responsibilities.