[PATCH for-4.2 3/4] block: Add bdrv_co_get_self_request()

[Max Reitz <mreitz@redhat.com>]

Signed-off-by: Max Reitz <mreitz@redhat.com>
---
 include/block/block_int.h |  1 +
 block/io.c                | 18 ++++++++++++++++++
 2 files changed, 19 insertions(+)

diff --git a/include/block/block_int.h b/include/block/block_int.h
index 32fa323b63..4fc531f9b2 100644
--- a/include/block/block_int.h
+++ b/include/block/block_int.h
@@ -1001,6 +1001,7 @@ void bdrv_unapply_subtree_drain(BdrvChild *child, BlockDriverState *old_parent);
 
 bool coroutine_fn bdrv_wait_serialising_requests(BdrvTrackedRequest *self);
 void bdrv_mark_request_serialising(BdrvTrackedRequest *req, uint64_t align);
+BdrvTrackedRequest *bdrv_co_get_self_request(BlockDriverState *bs);
 
 int get_tmp_filename(char *filename, int size);
 BlockDriver *bdrv_probe_all(const uint8_t *buf, int buf_size,
diff --git a/block/io.c b/block/io.c
index 039c0d49c9..e9205994a8 100644
--- a/block/io.c
+++ b/block/io.c
@@ -742,6 +742,24 @@ static bool is_request_serialising_and_aligned(BdrvTrackedRequest *req)
            (req->bytes == req->overlap_bytes);
 }
 
+/**
+ * Return the tracked request on @bs for the current coroutine, or
+ * NULL if there is none.
+ */
+BdrvTrackedRequest *bdrv_co_get_self_request(BlockDriverState *bs)
+{
+    BdrvTrackedRequest *req;
+    Coroutine *self = qemu_coroutine_self();
+
+    QLIST_FOREACH(req, &bs->tracked_requests, list) {
+        if (req->co == self) {
+            return req;
+        }
+    }
+
+    return NULL;
+}
+
 /**
  * Round a region to cluster boundaries
  */
-- 
2.21.0