multifd: Use proper maximum compression values

It happens that there are functions to calculate the worst possible
compression size for a packet.  Use them.

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

2 files changed, 4 insertions, 4 deletions

diff --git a/migration/multifd-zlib.c b/migration/multifd-zlib.c
index 9f6ebf1076..a2fec4d01d 100644
--- a/migration/multifd-zlib.c
+++ b/migration/multifd-zlib.c
@@ -54,8 +54,8 @@ static int zlib_send_setup(MultiFDSendParams *p, Error **errp)
         error_setg(errp, "multifd %u: deflate init failed", p->id);
         return -1;
     }
-    /* To be safe, we reserve twice the size of the packet */
-    z->zbuff_len = MULTIFD_PACKET_SIZE * 2;
+    /* This is the maxium size of the compressed buffer */
+    z->zbuff_len = compressBound(MULTIFD_PACKET_SIZE);
     z->zbuff = g_try_malloc(z->zbuff_len);
     if (!z->zbuff) {
         deflateEnd(&z->zs);
diff --git a/migration/multifd-zstd.c b/migration/multifd-zstd.c
index cc4e991724..97c08367d0 100644
--- a/migration/multifd-zstd.c
+++ b/migration/multifd-zstd.c
@@ -67,8 +67,8 @@ static int zstd_send_setup(MultiFDSendParams *p, Error **errp)
                    p->id, ZSTD_getErrorName(res));
         return -1;
     }
-    /* To be safe, we reserve twice the size of the packet */
-    z->zbuff_len = MULTIFD_PACKET_SIZE * 2;
+    /* This is the maxium size of the compressed buffer */
+    z->zbuff_len = ZSTD_compressBound(MULTIFD_PACKET_SIZE);
     z->zbuff = g_try_malloc(z->zbuff_len);
     if (!z->zbuff) {
         ZSTD_freeCStream(z->zcs);