[PATCH 2/2] migration/compress: disable compress if failed to setup

[Wei Yang <richardw.yang@linux.intel.com>]

In current logic, if compress_threads_save_setup() returns -1 the whole
migration would fail, while we could handle it gracefully by disable
compress.

Signed-off-by: Wei Yang <richardw.yang@linux.intel.com>
---
 migration/migration.c |  9 +++++++++
 migration/migration.h |  1 +
 migration/ram.c       | 15 ++++++++-------
 3 files changed, 18 insertions(+), 7 deletions(-)

diff --git a/migration/migration.c b/migration/migration.c
index 5f7e4d15e9..02b95f4223 100644
--- a/migration/migration.c
+++ b/migration/migration.c
@@ -2093,6 +2093,15 @@ bool migrate_use_compression(void)
     return s->enabled_capabilities[MIGRATION_CAPABILITY_COMPRESS];
 }
 
+void migrate_disable_compression(void)
+{
+    MigrationState *s;
+
+    s = migrate_get_current();
+
+    s->enabled_capabilities[MIGRATION_CAPABILITY_COMPRESS] = false;
+}
+
 int migrate_compress_level(void)
 {
     MigrationState *s;
diff --git a/migration/migration.h b/migration/migration.h
index 4f2fe193dc..51368d3a6e 100644
--- a/migration/migration.h
+++ b/migration/migration.h
@@ -309,6 +309,7 @@ bool migrate_use_return_path(void);
 uint64_t ram_get_total_transferred_pages(void);
 
 bool migrate_use_compression(void);
+void migrate_disable_compression(void);
 int migrate_compress_level(void);
 int migrate_compress_threads(void);
 int migrate_compress_wait_thread(void);
diff --git a/migration/ram.c b/migration/ram.c
index 96c9b16402..39279161a8 100644
--- a/migration/ram.c
+++ b/migration/ram.c
@@ -533,12 +533,12 @@ static void compress_threads_save_cleanup(void)
     comp_param = NULL;
 }
 
-static int compress_threads_save_setup(void)
+static void compress_threads_save_setup(void)
 {
     int i, thread_count;
 
     if (!migrate_use_compression()) {
-        return 0;
+        return;
     }
     thread_count = migrate_compress_threads();
     compress_threads = g_new0(QemuThread, thread_count);
@@ -569,11 +569,14 @@ static int compress_threads_save_setup(void)
                            do_data_compress, comp_param + i,
                            QEMU_THREAD_JOINABLE);
     }
-    return 0;
+    return;
 
 exit:
     compress_threads_save_cleanup();
-    return -1;
+    migrate_disable_compression();
+    error_report("%s: failed to setup compress threads, compress disabled",
+                 __func__);
+    return;
 }
 
 /* Multiple fd's */
@@ -3338,9 +3341,7 @@ static int ram_save_setup(QEMUFile *f, void *opaque)
     RAMState **rsp = opaque;
     RAMBlock *block;
 
-    if (compress_threads_save_setup()) {
-        return -1;
-    }
+    compress_threads_save_setup();
 
     /* migration has already setup the bitmap, reuse it. */
     if (!migration_in_colo_state()) {
-- 
2.17.1