[PATCH 03/14] block: Convert bdrv_io_unplug() to co_wrapper

[Kevin Wolf <kwolf@redhat.com>]

From: Emanuele Giuseppe Esposito <eesposit@redhat.com>

BlockDriver->bdrv_io_unplug is categorized as IO callback, and it
currently doesn't run in a coroutine. We should let it take a graph
rdlock since the callback traverses the block nodes graph, which however
is only possible in a coroutine.

The only caller of this function is blk_io_unplug(), therefore make
blk_io_unplug() a co_wrapper, so that we're always running in a
coroutine where the lock can be taken.

Signed-off-by: Emanuele Giuseppe Esposito <eesposit@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
---
 include/block/block-io.h          | 3 +--
 include/block/block_int-common.h  | 2 +-
 include/sysemu/block-backend-io.h | 4 +++-
 block/block-backend.c             | 4 ++--
 block/io.c                        | 4 ++--
 5 files changed, 9 insertions(+), 8 deletions(-)

diff --git a/include/block/block-io.h b/include/block/block-io.h
index d96168375e..3bf201f7f4 100644
--- a/include/block/block-io.h
+++ b/include/block/block-io.h
@@ -218,8 +218,7 @@ 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 4a1c1e348a..adccb4e540 100644
--- a/include/block/block_int-common.h
+++ b/include/block/block_int-common.h
@@ -730,7 +730,7 @@ struct BlockDriver {
 
     /* io queue for linux-aio */
     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 70b73f7d11..d8cc8d74f5 100644
--- a/include/sysemu/block-backend-io.h
+++ b/include/sysemu/block-backend-io.h
@@ -76,7 +76,9 @@ int blk_get_max_hw_iov(BlockBackend *blk);
 void coroutine_fn blk_co_io_plug(BlockBackend *blk);
 void co_wrapper blk_io_plug(BlockBackend *blk);
 
-void blk_io_unplug(BlockBackend *blk);
+void coroutine_fn blk_co_io_unplug(BlockBackend *blk);
+void co_wrapper 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,
diff --git a/block/block-backend.c b/block/block-backend.c
index f862fd1950..5a357f504a 100644
--- a/block/block-backend.c
+++ b/block/block-backend.c
@@ -2325,13 +2325,13 @@ 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();
 
     if (bs) {
-        bdrv_io_unplug(bs);
+        bdrv_co_io_unplug(bs);
     }
 }
 
diff --git a/block/io.c b/block/io.c
index 3d27836420..c33672e90a 100644
--- a/block/io.c
+++ b/block/io.c
@@ -3144,7 +3144,7 @@ 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();
@@ -3158,7 +3158,7 @@ void bdrv_io_unplug(BlockDriverState *bs)
     }
 
     QLIST_FOREACH(child, &bs->children, next) {
-        bdrv_io_unplug(child->bs);
+        bdrv_co_io_unplug(child->bs);
     }
 }
 
-- 
2.38.1