osc/rdma: Make sure shmem region isn't being searched while modified.

Signed-off-by: Austen Lauria <awlauria@us.ibm.com>

Author: awlauria

ompi/mca/osc/rdma/osc_rdma_dynamic.c

@@ -212,12 +212,13 @@ int ompi_osc_rdma_attach (struct ompi_win_t *win, void *base, size_t len)
         return ret;
     }
 
+
+    ompi_osc_rdma_lock_acquire_exclusive (module, my_peer, offsetof (ompi_osc_rdma_state_t, regions_lock));
+
     /* region is in flux */
     module->state->region_count = -1;
     opal_atomic_wmb ();
 
-    ompi_osc_rdma_lock_acquire_exclusive (module, my_peer, offsetof (ompi_osc_rdma_state_t, regions_lock));
-
     /* do a binary seach for where the region should be inserted */
     if (region_count) {
         region = find_insertion_point ((ompi_osc_rdma_region_t *) module->state->regions, 0, region_count - 1,
@@ -357,6 +358,7 @@ int ompi_osc_rdma_detach (struct ompi_win_t *win, const void *base)
     module->dynamic_handles[region_count - 1] = NULL;
 
     module->state->region_count = ((region_id + 1) << 32) | (region_count - 1);
+    opal_atomic_mb ();
 
     ompi_osc_rdma_lock_release_exclusive (module, &my_peer->super, offsetof (ompi_osc_rdma_state_t, regions_lock));
 
@@ -465,6 +467,8 @@ int ompi_osc_rdma_find_dynamic_region (ompi_osc_rdma_module_t *module, ompi_osc_
     OSC_RDMA_VERBOSE(MCA_BASE_VERBOSE_TRACE, "locating dynamic memory region matching: {%" PRIx64 ", %" PRIx64 "}"
                      " (len %lu)", base, base + len, (unsigned long) len);
 
+    // Make sure region isn't being touched.
+    ompi_osc_rdma_lock_acquire_exclusive (module, peer, offsetof (ompi_osc_rdma_state_t, regions_lock));
     if (!ompi_osc_rdma_peer_local_state (peer)) {
         ret = ompi_osc_rdma_refresh_dynamic_region (module, dy_peer);
         if (OMPI_SUCCESS != ret) {
@@ -478,6 +482,7 @@ int ompi_osc_rdma_find_dynamic_region (ompi_osc_rdma_module_t *module, ompi_osc_
         regions = (ompi_osc_rdma_region_t *) peer_state->regions;
         region_count = peer_state->region_count;
     }
+    ompi_osc_rdma_lock_release_exclusive (module, peer, offsetof (ompi_osc_rdma_state_t, regions_lock));
 
     *region = ompi_osc_rdma_find_region_containing (regions, 0, region_count - 1, (intptr_t) base, bound, module->region_size, NULL);
     if (!*region) {