[PATCH] migration: fix maybe-uninitialized warning

[Paolo Bonzini <pbonzini@redhat.com>]

From: Marc-André Lureau <marcandre.lureau@redhat.com>

../migration/ram.c: In function ‘multifd_recv_thread’:
/home/elmarco/src/qq/include/qapi/error.h:165:5: error: ‘block’ may be used uninitialized in this function [-Werror=maybe-uninitialized]
  165 |     error_setg_internal((errp), __FILE__, __LINE__, __func__,   \
      |     ^~~~~~~~~~~~~~~~~~~
../migration/ram.c:818:15: note: ‘block’ was declared here
  818 |     RAMBlock *block;
      |               ^~~~~

Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
---
 migration/ram.c | 20 +++++++++++---------
 1 file changed, 11 insertions(+), 9 deletions(-)

diff --git a/migration/ram.c b/migration/ram.c
index 5078f94..7dd7f81 100644
--- a/migration/ram.c
+++ b/migration/ram.c
@@ -864,15 +864,17 @@ static int multifd_recv_unfill_packet(MultiFDRecvParams *p, Error **errp)
     p->next_packet_size = be32_to_cpu(packet->next_packet_size);
     p->packet_num = be64_to_cpu(packet->packet_num);
 
-    if (p->pages->used) {
-        /* make sure that ramblock is 0 terminated */
-        packet->ramblock[255] = 0;
-        block = qemu_ram_block_by_name(packet->ramblock);
-        if (!block) {
-            error_setg(errp, "multifd: unknown ram block %s",
-                       packet->ramblock);
-            return -1;
-        }
+    if (p->pages->used == 0) {
+        return 0;
+    }
+
+    /* make sure that ramblock is 0 terminated */
+    packet->ramblock[255] = 0;
+    block = qemu_ram_block_by_name(packet->ramblock);
+    if (!block) {
+        error_setg(errp, "multifd: unknown ram block %s",
+                   packet->ramblock);
+        return -1;
     }
 
     for (i = 0; i < p->pages->used; i++) {
-- 
1.8.3.1