[PATCH v2 5/7] block-copy: add QemuMutex lock for BlockCopyCallState list

[Emanuele Giuseppe Esposito]

As for BlockCopyTask, add a lock to protect BlockCopyCallState
ret and sleep_state fields. Also move ret, finished and cancelled
in the OUT fields of BlockCopyCallState.

Here a QemuMutex is used to protect QemuCoSleep field, since it
can be concurrently invoked also from outside threads.

.finished, .cancelled and reads to .ret and .error_is_read will be
protected in the following patch.

.sleep state is handled in the series "coroutine: new sleep/wake API"

Signed-off-by: Emanuele Giuseppe Esposito <eesposit@redhat.com>
---
 block/block-copy.c | 27 +++++++++++++++++++--------
 1 file changed, 19 insertions(+), 8 deletions(-)

diff --git a/block/block-copy.c b/block/block-copy.c
index 3a949fab64..d5ed5932b0 100644
--- a/block/block-copy.c
+++ b/block/block-copy.c
@@ -55,13 +55,14 @@ typedef struct BlockCopyCallState {
     QLIST_ENTRY(BlockCopyCallState) list;
 
     /* State */
-    int ret;
     bool finished;
-    QemuCoSleep sleep;
-    bool cancelled;
+    QemuCoSleep sleep; /* TODO: protect API with a lock */
 
     /* OUT parameters */
+    bool cancelled;
+    /* Fields protected by calls_lock in BlockCopyState */
     bool error_is_read;
+    int ret;
 } BlockCopyCallState;
 
 typedef struct BlockCopyTask {
@@ -110,6 +111,7 @@ typedef struct BlockCopyState {
     BlockCopyMethod method;
     CoMutex tasks_lock;
     QLIST_HEAD(, BlockCopyTask) tasks; /* All tasks from all block-copy calls 
*/
+    QemuMutex calls_lock;
     QLIST_HEAD(, BlockCopyCallState) calls;
     /* State fields that use a thread-safe API */
     BdrvDirtyBitmap *copy_bitmap;
@@ -289,6 +291,7 @@ void block_copy_state_free(BlockCopyState *s)
     }
 
     ratelimit_destroy(&s->rate_limit);
+    qemu_mutex_destroy(&s->calls_lock);
     bdrv_release_dirty_bitmap(s->copy_bitmap);
     shres_destroy(s->mem);
     g_free(s);
@@ -349,6 +352,7 @@ BlockCopyState *block_copy_state_new(BdrvChild *source, 
BdrvChild *target,
 
     ratelimit_init(&s->rate_limit);
     qemu_co_mutex_init(&s->tasks_lock);
+    qemu_mutex_init(&s->calls_lock);
     QLIST_INIT(&s->tasks);
     QLIST_INIT(&s->calls);
 
@@ -492,11 +496,14 @@ static coroutine_fn int block_copy_task_entry(AioTask 
*task)
 
     ret = block_copy_do_copy(t->s, t->offset, t->bytes, t->zeroes,
                              &error_is_read);
-    if (ret < 0 && !t->call_state->ret) {
-        t->call_state->ret = ret;
-        t->call_state->error_is_read = error_is_read;
-    } else {
-        progress_work_done(t->s->progress, t->bytes);
+
+    WITH_QEMU_LOCK_GUARD(&t->s->calls_lock) {
+        if (ret < 0 && !t->call_state->ret) {
+            t->call_state->ret = ret;
+            t->call_state->error_is_read = error_is_read;
+        } else {
+            progress_work_done(t->s->progress, t->bytes);
+        }
     }
     co_put_to_shres(t->s->mem, t->bytes);
     block_copy_task_end(t, ret);
@@ -740,7 +747,9 @@ static int coroutine_fn 
block_copy_common(BlockCopyCallState *call_state)
 {
     int ret;
 
+    qemu_mutex_lock(&call_state->s->calls_lock);
     QLIST_INSERT_HEAD(&call_state->s->calls, call_state, list);
+    qemu_mutex_unlock(&call_state->s->calls_lock);
 
     do {
         ret = block_copy_dirty_clusters(call_state);
@@ -767,7 +776,9 @@ static int coroutine_fn 
block_copy_common(BlockCopyCallState *call_state)
         call_state->cb(call_state->cb_opaque);
     }
 
+    qemu_mutex_lock(&call_state->s->calls_lock);
     QLIST_REMOVE(call_state, list);
+    qemu_mutex_unlock(&call_state->s->calls_lock);
 
     return ret;
 }
-- 
2.30.2