[LU-15929] Correct the net selection for router ping

• Type: Bug
• Resolution: Fixed
• Priority: Minor
• Fix Version/s: Lustre 2.16.0
• Severity: 3
• Assignee: Chris Horn
• Reporter: Chris Horn

Description

lnet_select_best_ni_on_local_net() contains logic for restricting
the NI selection to a net specified by lnet_peer::lp_disc_net_id. The
purpose of this is to ensure that LNet peers ping every interface on
a router at a regular interval as part of the LNet router health
feature. However, this logic is flawed in because lnet_msg_discovery()
is used to determine whether the message being sent is a discovery
message, but that function actually determines whether a give message
can trigger discovery