[PATCH 14/15] block: convert bdrv_io_unplug in generated_co_wrapper_simple

[Emanuele Giuseppe Esposito <eesposit@redhat.com>]

BlockDriver->bdrv_io_unplug is categorized as IO callback, and
it currently doesn't run in a coroutine.
This makes very difficult to add the graph rdlock, since the
callback traverses the block nodes graph.

The only caller of this function is blk_unplug, therefore
make blk_unplug a generated_co_wrapper_simple, so that
it always creates a new coroutine, and then make bdrv_unplug
coroutine_fn.

Signed-off-by: Emanuele Giuseppe Esposito <eesposit@redhat.com>
---
 block/block-backend.c             | 5 +++--
 block/io.c                        | 5 +++--
 include/block/block-io.h          | 3 +--
 include/block/block_int-common.h  | 2 +-
 include/sysemu/block-backend-io.h | 4 +++-
 5 files changed, 11 insertions(+), 8 deletions(-)

diff --git a/block/block-backend.c b/block/block-backend.c
index 826a936beb..3b10e35ea4 100644
--- a/block/block-backend.c
+++ b/block/block-backend.c
@@ -2340,13 +2340,14 @@ void coroutine_fn blk_co_io_plug(BlockBackend *blk)
     }
 }
 
-void blk_io_unplug(BlockBackend *blk)
+void coroutine_fn blk_co_io_unplug(BlockBackend *blk)
 {
     BlockDriverState *bs = blk_bs(blk);
     IO_CODE();
+    assert_bdrv_graph_readable();
 
     if (bs) {
-        bdrv_io_unplug(bs);
+        bdrv_co_io_unplug(bs);
     }
 }
 
diff --git a/block/io.c b/block/io.c
index d3b8c1e4b2..48a94dd384 100644
--- a/block/io.c
+++ b/block/io.c
@@ -3086,10 +3086,11 @@ void coroutine_fn bdrv_co_io_plug(BlockDriverState *bs)
     }
 }
 
-void bdrv_io_unplug(BlockDriverState *bs)
+void coroutine_fn bdrv_co_io_unplug(BlockDriverState *bs)
 {
     BdrvChild *child;
     IO_CODE();
+    assert_bdrv_graph_readable();
 
     assert(bs->io_plugged);
     if (qatomic_fetch_dec(&bs->io_plugged) == 1) {
@@ -3100,7 +3101,7 @@ void bdrv_io_unplug(BlockDriverState *bs)
     }
 
     QLIST_FOREACH(child, &bs->children, next) {
-        bdrv_io_unplug(child->bs);
+        bdrv_co_io_unplug(child->bs);
     }
 }
 
diff --git a/include/block/block-io.h b/include/block/block-io.h
index a045643b26..f93357681a 100644
--- a/include/block/block-io.h
+++ b/include/block/block-io.h
@@ -216,8 +216,7 @@ void bdrv_coroutine_enter(BlockDriverState *bs, Coroutine *co);
 AioContext *child_of_bds_get_parent_aio_context(BdrvChild *c);
 
 void coroutine_fn bdrv_co_io_plug(BlockDriverState *bs);
-
-void bdrv_io_unplug(BlockDriverState *bs);
+void coroutine_fn bdrv_co_io_unplug(BlockDriverState *bs);
 
 bool coroutine_fn bdrv_co_can_store_new_dirty_bitmap(BlockDriverState *bs,
                                                      const char *name,
diff --git a/include/block/block_int-common.h b/include/block/block_int-common.h
index ed96bc3241..3ab3fa45a2 100644
--- a/include/block/block_int-common.h
+++ b/include/block/block_int-common.h
@@ -787,7 +787,7 @@ struct BlockDriver {
 
     /* io queue for linux-aio. Called with graph rdlock taken. */
     void coroutine_fn (*bdrv_io_plug)(BlockDriverState *bs);
-    void (*bdrv_io_unplug)(BlockDriverState *bs);
+    void coroutine_fn (*bdrv_io_unplug)(BlockDriverState *bs);
 
     /**
      * bdrv_drain_begin is called if implemented in the beginning of a
diff --git a/include/sysemu/block-backend-io.h b/include/sysemu/block-backend-io.h
index 703fcc3ac5..c8df7320f7 100644
--- a/include/sysemu/block-backend-io.h
+++ b/include/sysemu/block-backend-io.h
@@ -90,7 +90,9 @@ int blk_get_max_hw_iov(BlockBackend *blk);
 void coroutine_fn blk_co_io_plug(BlockBackend *blk);
 void generated_co_wrapper_simple blk_io_plug(BlockBackend *blk);
 
-void blk_io_unplug(BlockBackend *blk);
+void coroutine_fn blk_co_io_unplug(BlockBackend *blk);
+void generated_co_wrapper_simple blk_io_unplug(BlockBackend *blk);
+
 AioContext *blk_get_aio_context(BlockBackend *blk);
 BlockAcctStats *blk_get_stats(BlockBackend *blk);
 void *blk_aio_get(const AIOCBInfo *aiocb_info, BlockBackend *blk,
-- 
2.31.1