[RFC 09/24] block/block-copy: alloc task on each iteration

[Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>]

We are going to use aio-task-pool API, so tasks will be handled in
parallel. We need therefore separate allocated task on each iteration.
Introduce this logic now.

Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
---
 block/block-copy.c | 18 +++++++++++-------
 1 file changed, 11 insertions(+), 7 deletions(-)

diff --git a/block/block-copy.c b/block/block-copy.c
index b00cbfc841..956b4b55e7 100644
--- a/block/block-copy.c
+++ b/block/block-copy.c
@@ -111,9 +111,11 @@ static bool coroutine_fn block_copy_wait_one(BlockCopyState *s, int64_t start,
 }
 
 /* Called only on full-dirty region */
-static void block_copy_task_begin(BlockCopyState *s, BlockCopyTask *task,
-                                  int64_t offset, int64_t bytes)
+static BlockCopyTask *block_copy_task_create(BlockCopyState *s,
+                                             int64_t offset, int64_t bytes)
 {
+    BlockCopyTask *task = g_new(BlockCopyTask, 1);
+
     assert(!block_copy_find_task(s, offset, bytes));
 
     bdrv_reset_dirty_bitmap(s->copy_bitmap, offset, bytes);
@@ -122,6 +124,8 @@ static void block_copy_task_begin(BlockCopyState *s, BlockCopyTask *task,
     task->bytes = bytes;
     qemu_co_queue_init(&task->wait_queue);
     QLIST_INSERT_HEAD(&s->tasks, task, list);
+
+    return task;
 }
 
 static void coroutine_fn block_copy_task_shrink(BlockCopyState *s,
@@ -454,7 +458,7 @@ static int coroutine_fn block_copy_dirty_clusters(BlockCopyState *s,
     assert(QEMU_IS_ALIGNED(bytes, s->cluster_size));
 
     while (bytes) {
-        BlockCopyTask task;
+        g_autofree BlockCopyTask *task = NULL;
         int64_t next_zero, cur_bytes, status_bytes;
 
         if (!bdrv_dirty_bitmap_get(s->copy_bitmap, offset)) {
@@ -475,12 +479,12 @@ static int coroutine_fn block_copy_dirty_clusters(BlockCopyState *s,
             assert(next_zero < offset + cur_bytes); /* no need to do MIN() */
             cur_bytes = next_zero - offset;
         }
-        block_copy_task_begin(s, &task, offset, cur_bytes);
+        task = block_copy_task_create(s, offset, cur_bytes);
 
         ret = block_copy_block_status(s, offset, cur_bytes, &status_bytes);
-        block_copy_task_shrink(s, &task, status_bytes);
+        block_copy_task_shrink(s, task, status_bytes);
         if (s->skip_unallocated && !(ret & BDRV_BLOCK_ALLOCATED)) {
-            block_copy_task_end(s, &task, 0);
+            block_copy_task_end(s, task, 0);
             s->progress_reset_callback(s->progress_opaque);
             trace_block_copy_skip_range(s, offset, status_bytes);
             offset += status_bytes;
@@ -496,7 +500,7 @@ static int coroutine_fn block_copy_dirty_clusters(BlockCopyState *s,
         ret = block_copy_do_copy(s, offset, cur_bytes, ret & BDRV_BLOCK_ZERO,
                                  error_is_read);
         co_put_to_shres(s->mem, cur_bytes);
-        block_copy_task_end(s, &task, ret);
+        block_copy_task_end(s, task, ret);
         if (ret < 0) {
             return ret;
         }
-- 
2.21.0