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-rw-r--r--block/block-backend.c7
-rw-r--r--include/block/block-common.h3
-rw-r--r--scripts/block-coroutine-wrapper.py25
3 files changed, 24 insertions, 11 deletions
diff --git a/block/block-backend.c b/block/block-backend.c
index ca537cd0ad..26447664ab 100644
--- a/block/block-backend.c
+++ b/block/block-backend.c
@@ -2394,9 +2394,14 @@ void blk_op_unblock_all(BlockBackend *blk, Error *reason)
 
 AioContext *blk_get_aio_context(BlockBackend *blk)
 {
-    BlockDriverState *bs = blk_bs(blk);
+    BlockDriverState *bs;
     IO_CODE();
 
+    if (!blk) {
+        return qemu_get_aio_context();
+    }
+
+    bs = blk_bs(blk);
     if (bs) {
         AioContext *ctx = bdrv_get_aio_context(blk_bs(blk));
         assert(ctx == blk->ctx);
diff --git a/include/block/block-common.h b/include/block/block-common.h
index 93196229ac..e15395f2cb 100644
--- a/include/block/block-common.h
+++ b/include/block/block-common.h
@@ -65,6 +65,9 @@
  * scheduling a BH in the bottom half that runs the respective non-coroutine
  * function. The coroutine yields after scheduling the BH and is reentered when
  * the wrapped function returns.
+ *
+ * If the first parameter of the function is a BlockDriverState, BdrvChild or
+ * BlockBackend pointer, the AioContext lock for it is taken in the wrapper.
  */
 #define no_co_wrapper
 
diff --git a/scripts/block-coroutine-wrapper.py b/scripts/block-coroutine-wrapper.py
index 60e9b3107c..d4a183db61 100644
--- a/scripts/block-coroutine-wrapper.py
+++ b/scripts/block-coroutine-wrapper.py
@@ -88,16 +88,7 @@ class FuncDecl:
                 raise ValueError(f"no_co function can't be rdlock: {self.name}")
             self.target_name = f'{subsystem}_{subname}'
 
-        t = self.args[0].type
-        if t == 'BlockDriverState *':
-            ctx = 'bdrv_get_aio_context(bs)'
-        elif t == 'BdrvChild *':
-            ctx = 'bdrv_get_aio_context(child->bs)'
-        elif t == 'BlockBackend *':
-            ctx = 'blk_get_aio_context(blk)'
-        else:
-            ctx = 'qemu_get_aio_context()'
-        self.ctx = ctx
+        self.ctx = self.gen_ctx()
 
         self.get_result = 's->ret = '
         self.ret = 'return s.ret;'
@@ -109,6 +100,17 @@ class FuncDecl:
             self.co_ret = ''
             self.return_field = ''
 
+    def gen_ctx(self, prefix: str = '') -> str:
+        t = self.args[0].type
+        if t == 'BlockDriverState *':
+            return f'bdrv_get_aio_context({prefix}bs)'
+        elif t == 'BdrvChild *':
+            return f'bdrv_get_aio_context({prefix}child->bs)'
+        elif t == 'BlockBackend *':
+            return f'blk_get_aio_context({prefix}blk)'
+        else:
+            return 'qemu_get_aio_context()'
+
     def gen_list(self, format: str) -> str:
         return ', '.join(format.format_map(arg.__dict__) for arg in self.args)
 
@@ -262,8 +264,11 @@ typedef struct {struct_name} {{
 static void {name}_bh(void *opaque)
 {{
     {struct_name} *s = opaque;
+    AioContext *ctx = {func.gen_ctx('s->')};
 
+    aio_context_acquire(ctx);
     {func.get_result}{name}({ func.gen_list('s->{name}') });
+    aio_context_release(ctx);
 
     aio_co_wake(s->co);
 }}