When using eager RDMA in debug builds the openib btl generates a
sequence number for each send. The code independently updated the head
index and the sequence number for the eager rdma transaction. If
multiple threads enter this code at the same time and run in the
following order:
thread 1: update sequence (0 -> 1)
thread 2: update sequence (1 -> 2)
thread 2: update head (0 -> 1)
thread 1: update head (1 -> 2)
the sequence number for head[0] gets 1 and the sequence number for
head[1] gets 0. The fix is to generate the sequence number from the
head index.
Signed-off-by: Nathan Hjelm <hjelmn@lanl.gov>
c101385f64