transport/ib-verbs: synchronize ib_verbs_recv_completion_proc with ib_verbs_receive so that the former doesn't overwrite the pointer from which latter reads.

- There can be a condition wherein,
    1. the thread executing ib_verbs_recv_completion_proc (thr 1) stores the
       buffer pointer and notifies the upper translators about a POLLIN event.
    2. the thread waiting for events on socket (thr 2) calls transport_receive,
       but in ib_verbs_receive it has not still read the data.
    3. thr 1 receives work completion event for another work request and
       overwrites the buffer pointer.
    4. thr 2 reads from the new pointer there by missing the data stored in
       buffer pointed by pointer which got overwritten.

Signed-off-by: Raghavendra G <raghavendra@gluster.com>
Signed-off-by: Anand V. Avati <avati@dev.gluster.com>

BUG: 382 (Data can be lost before it is read in ib_verbs_receive.)
URL: http://bugs.gluster.com/cgi-bin/bugzilla3/show_bug.cgi?id=382

0 files changed, 0 insertions, 0 deletions