- start_wrq_wr must not drain the wr_list if there are incomplete_wrs
pending. This can happen when a t4_wrq_tx runs between two
start_wrq_wr.
- commit_wrq_wr must examine the cookie's pidx and ndesc with the
queue's lock held. Otherwise there is a bad race when incomplete WRs
are being completed and commit_wrq_wr for the WR that is ahead in the
queue updates the next incomplete WR's cookie's pidx/ndesc but the
commit_wrq_wr for the second one is using stale values that it read
without the lock.
MFC after: 1 week
Sponsored by: Chelsio Communications