[PULL 17/29] block: Mark bdrv_co_io_(un)plug() and callers GRAPH_RDLOCK

[Kevin Wolf <kwolf@redhat.com>]

This adds GRAPH_RDLOCK annotations to declare that callers of
bdrv_co_io_plug() and bdrv_co_io_unplug() need to hold a reader lock for
the graph.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Message-Id: <20230203152202.49054-18-kwolf@redhat.com>
Reviewed-by: Emanuele Giuseppe Esposito <eesposit@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
---
 include/block/block-io.h         | 4 ++--
 include/block/block_int-common.h | 5 +++--
 block/block-backend.c            | 2 ++
 block/io.c                       | 2 ++
 4 files changed, 9 insertions(+), 4 deletions(-)

diff --git a/include/block/block-io.h b/include/block/block-io.h
index c551742a86..b8f99741a3 100644
--- a/include/block/block-io.h
+++ b/include/block/block-io.h
@@ -233,8 +233,8 @@ void coroutine_fn bdrv_co_leave(BlockDriverState *bs, AioContext *old_ctx);
 
 AioContext *child_of_bds_get_parent_aio_context(BdrvChild *c);
 
-void coroutine_fn bdrv_co_io_plug(BlockDriverState *bs);
-void coroutine_fn bdrv_co_io_unplug(BlockDriverState *bs);
+void coroutine_fn GRAPH_RDLOCK bdrv_co_io_plug(BlockDriverState *bs);
+void coroutine_fn GRAPH_RDLOCK 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 6b8fd22c71..61f894bcf6 100644
--- a/include/block/block_int-common.h
+++ b/include/block/block_int-common.h
@@ -735,8 +735,9 @@ struct BlockDriver {
                                              BlkdebugEvent event);
 
     /* io queue for linux-aio */
-    void coroutine_fn (*bdrv_co_io_plug)(BlockDriverState *bs);
-    void coroutine_fn (*bdrv_co_io_unplug)(BlockDriverState *bs);
+    void coroutine_fn GRAPH_RDLOCK_PTR (*bdrv_co_io_plug)(BlockDriverState *bs);
+    void coroutine_fn GRAPH_RDLOCK_PTR (*bdrv_co_io_unplug)(
+        BlockDriverState *bs);
 
     /**
      * bdrv_drain_begin is called if implemented in the beginning of a
diff --git a/block/block-backend.c b/block/block-backend.c
index fdb1e1d5f7..3661a066b3 100644
--- a/block/block-backend.c
+++ b/block/block-backend.c
@@ -2328,6 +2328,7 @@ void coroutine_fn blk_co_io_plug(BlockBackend *blk)
 {
     BlockDriverState *bs = blk_bs(blk);
     IO_CODE();
+    GRAPH_RDLOCK_GUARD();
 
     if (bs) {
         bdrv_co_io_plug(bs);
@@ -2338,6 +2339,7 @@ void coroutine_fn blk_co_io_unplug(BlockBackend *blk)
 {
     BlockDriverState *bs = blk_bs(blk);
     IO_CODE();
+    GRAPH_RDLOCK_GUARD();
 
     if (bs) {
         bdrv_co_io_unplug(bs);
diff --git a/block/io.c b/block/io.c
index d9c1594960..b5459c2f41 100644
--- a/block/io.c
+++ b/block/io.c
@@ -3153,6 +3153,7 @@ void coroutine_fn bdrv_co_io_plug(BlockDriverState *bs)
 {
     BdrvChild *child;
     IO_CODE();
+    assert_bdrv_graph_readable();
 
     QLIST_FOREACH(child, &bs->children, next) {
         bdrv_co_io_plug(child->bs);
@@ -3170,6 +3171,7 @@ 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) {
-- 
2.39.2