[Qemu-devel] [PATCH v10 11/24] migration: terminate_* can be called for other threads

[Juan Quintela <quintela@redhat.com>]

Once there, make  count field to always be accessed with atomic
operations.  To make blocking operations, we need to know that the
thread is running, so create a bool to indicate that.

Signed-off-by: Juan Quintela <quintela@redhat.com>
---
 migration/ram.c | 30 ++++++++++++++++++++----------
 1 file changed, 20 insertions(+), 10 deletions(-)

diff --git a/migration/ram.c b/migration/ram.c
index 4a56a85d53..977e675f46 100644
--- a/migration/ram.c
+++ b/migration/ram.c
@@ -400,6 +400,7 @@ struct MultiFDSendParams {
     QemuThread thread;
     QemuSemaphore sem;
     QemuMutex mutex;
+    bool running;
     bool quit;
 };
 typedef struct MultiFDSendParams MultiFDSendParams;
@@ -424,7 +425,7 @@ static void terminate_multifd_send_threads(Error *errp)
         }
     }
 
-    for (i = 0; i < multifd_send_state->count; i++) {
+    for (i = 0; i < migrate_multifd_channels(); i++) {
         MultiFDSendParams *p = &multifd_send_state->params[i];
 
         qemu_mutex_lock(&p->mutex);
@@ -443,10 +444,13 @@ int multifd_save_cleanup(Error **errp)
         return 0;
     }
     terminate_multifd_send_threads(NULL);
-    for (i = 0; i < multifd_send_state->count; i++) {
+    for (i = 0; i < migrate_multifd_channels(); i++) {
         MultiFDSendParams *p = &multifd_send_state->params[i];
 
-        qemu_thread_join(&p->thread);
+        if (p->running) {
+            qemu_thread_join(&p->thread);
+            p->running = false;
+        }
         qemu_mutex_destroy(&p->mutex);
         qemu_sem_destroy(&p->sem);
         g_free(p->name);
@@ -487,7 +491,7 @@ int multifd_save_setup(void)
     thread_count = migrate_multifd_channels();
     multifd_send_state = g_malloc0(sizeof(*multifd_send_state));
     multifd_send_state->params = g_new0(MultiFDSendParams, thread_count);
-    multifd_send_state->count = 0;
+    atomic_set(&multifd_send_state->count, 0);
     for (i = 0; i < thread_count; i++) {
         MultiFDSendParams *p = &multifd_send_state->params[i];
 
@@ -496,10 +500,11 @@ int multifd_save_setup(void)
         p->quit = false;
         p->id = i;
         p->name = g_strdup_printf("multifdsend_%d", i);
+        p->running = true;
         qemu_thread_create(&p->thread, p->name, multifd_send_thread, p,
                            QEMU_THREAD_JOINABLE);
 
-        multifd_send_state->count++;
+        atomic_inc(&multifd_send_state->count);
     }
     return 0;
 }
@@ -510,6 +515,7 @@ struct MultiFDRecvParams {
     QemuThread thread;
     QemuSemaphore sem;
     QemuMutex mutex;
+    bool running;
     bool quit;
 };
 typedef struct MultiFDRecvParams MultiFDRecvParams;
@@ -534,7 +540,7 @@ static void terminate_multifd_recv_threads(Error *errp)
         }
     }
 
-    for (i = 0; i < multifd_recv_state->count; i++) {
+    for (i = 0; i < migrate_multifd_channels(); i++) {
         MultiFDRecvParams *p = &multifd_recv_state->params[i];
 
         qemu_mutex_lock(&p->mutex);
@@ -553,10 +559,13 @@ int multifd_load_cleanup(Error **errp)
         return 0;
     }
     terminate_multifd_recv_threads(NULL);
-    for (i = 0; i < multifd_recv_state->count; i++) {
+    for (i = 0; i < migrate_multifd_channels(); i++) {
         MultiFDRecvParams *p = &multifd_recv_state->params[i];
 
-        qemu_thread_join(&p->thread);
+        if (p->running) {
+            qemu_thread_join(&p->thread);
+            p->running = false;
+        }
         qemu_mutex_destroy(&p->mutex);
         qemu_sem_destroy(&p->sem);
         g_free(p->name);
@@ -598,7 +607,7 @@ int multifd_load_setup(void)
     thread_count = migrate_multifd_channels();
     multifd_recv_state = g_malloc0(sizeof(*multifd_recv_state));
     multifd_recv_state->params = g_new0(MultiFDRecvParams, thread_count);
-    multifd_recv_state->count = 0;
+    atomic_set(&multifd_recv_state->count, 0);
     for (i = 0; i < thread_count; i++) {
         MultiFDRecvParams *p = &multifd_recv_state->params[i];
 
@@ -607,9 +616,10 @@ int multifd_load_setup(void)
         p->quit = false;
         p->id = i;
         p->name = g_strdup_printf("multifdrecv_%d", i);
+        p->running = true;
         qemu_thread_create(&p->thread, p->name, multifd_recv_thread, p,
                            QEMU_THREAD_JOINABLE);
-        multifd_recv_state->count++;
+        atomic_inc(&multifd_recv_state->count);
     }
     return 0;
 }
-- 
2.14.3