LU-16290 lnet: Signal completion on ping send failure

LU-16290 lnet: Signal completion on ping send failure

Call complete() on the ping_data::completion if we get
LNET_EVENT_SEND with non-zero status. Otherwise the thread which
issued the ping is stuck waiting for the full ping timeout.

A pd_unlinked member is added to struct ping_data to indicate whether
the associated MD has been unlinked. This is checked by lnet_ping() to
determine whether it needs to explicitly called LNetMDUnlink().

Lastly, in cases where we do not receive a reply, we now return the
value of pd.rc, if it is non-zero, rather than -EIO. This can provide
more information about the underlying ping failure.

HPE-bug-id: LUS-11317
Test-Parameters: trivial testlist=sanity-lnet
Signed-off-by: Chris Horn <chris.horn@hpe.com>
Change-Id: I1bc573cf7397e319993fa8aabb31c5f3b59768e7
Reviewed-on: https://review.whamcloud.com/c/fs/lustre-release/+/49020
Tested-by: jenkins <devops@whamcloud.com>
Tested-by: Maloo <maloo@whamcloud.com>
Reviewed-by: Serguei Smirnov <ssmirnov@whamcloud.com>
Reviewed-by: Frank Sehr <fsehr@whamcloud.com>
Reviewed-by: Oleg Drokin <green@whamcloud.com>