Allow rdma_delete_block to work without the hash

In the next patch we remove the hash on the destination,
rdma_delete_block does two things with the hash which can be avoided:
  a) The caller passes the offset and rdma_delete_block looks it up
     in the hash; fixed by getting the caller to pass the block
  b) The hash gets recreated after deletion; fixed by making that
     conditional on the hash being initialised.

While this function is currently only used during cleanup, Michael
asked that we keep it general for future dynamic block registration
work.

Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>

1 files changed, 16 insertions, 11 deletions

diff --git a/migration/rdma.c b/migration/rdma.c
index fab736e9ca..347d380912 100644
--- a/migration/rdma.c
+++ b/migration/rdma.c
@@ -618,16 +618,19 @@ static int qemu_rdma_init_ram_blocks(RDMAContext *rdma)
     return 0;
 }
 
-static int rdma_delete_block(RDMAContext *rdma, ram_addr_t block_offset)
+/*
+ * Note: If used outside of cleanup, the caller must ensure that the destination
+ * block structures are also updated
+ */
+static int rdma_delete_block(RDMAContext *rdma, RDMALocalBlock *block)
 {
     RDMALocalBlocks *local = &rdma->local_ram_blocks;
-    RDMALocalBlock *block = g_hash_table_lookup(rdma->blockmap,
-        (void *) block_offset);
     RDMALocalBlock *old = local->block;
     int x;
 
-    assert(block);
-
+    if (rdma->blockmap) {
+        g_hash_table_remove(rdma->blockmap, (void *)(uintptr_t)block->offset);
+    }
     if (block->pmr) {
         int j;
 
@@ -660,8 +663,11 @@ static int rdma_delete_block(RDMAContext *rdma, ram_addr_t block_offset)
     g_free(block->block_name);
     block->block_name = NULL;
 
-    for (x = 0; x < local->nb_blocks; x++) {
-        g_hash_table_remove(rdma->blockmap, (void *)(uintptr_t)old[x].offset);
+    if (rdma->blockmap) {
+        for (x = 0; x < local->nb_blocks; x++) {
+            g_hash_table_remove(rdma->blockmap,
+                                (void *)(uintptr_t)old[x].offset);
+        }
     }
 
     if (local->nb_blocks > 1) {
@@ -683,8 +689,7 @@ static int rdma_delete_block(RDMAContext *rdma, ram_addr_t block_offset)
         local->block = NULL;
     }
 
-    trace_rdma_delete_block(local->nb_blocks,
-                           (uintptr_t)block->local_host_addr,
+    trace_rdma_delete_block(block, (uintptr_t)block->local_host_addr,
                            block->offset, block->length,
                             (uintptr_t)(block->local_host_addr + block->length),
                            BITS_TO_LONGS(block->nb_chunks) *
@@ -694,7 +699,7 @@ static int rdma_delete_block(RDMAContext *rdma, ram_addr_t block_offset)
 
     local->nb_blocks--;
 
-    if (local->nb_blocks) {
+    if (local->nb_blocks && rdma->blockmap) {
         for (x = 0; x < local->nb_blocks; x++) {
             g_hash_table_insert(rdma->blockmap,
                                 (void *)(uintptr_t)local->block[x].offset,
@@ -2222,7 +2227,7 @@ static void qemu_rdma_cleanup(RDMAContext *rdma)
 
     if (rdma->local_ram_blocks.block) {
         while (rdma->local_ram_blocks.nb_blocks) {
-            rdma_delete_block(rdma, rdma->local_ram_blocks.block->offset);
+            rdma_delete_block(rdma, &rdma->local_ram_blocks.block[0]);
         }
     }