block: mark change_aio_ctx() callback and instances as GRAPH_RDLOCK(_PTR)

This is a small step in preparation to mark bdrv_drained_begin() as
GRAPH_UNLOCKED. More concretely, it is in preparation to move the
drain out of bdrv_change_aio_context() and marking that function as
GRAPH_RDLOCK.

Signed-off-by: Fiona Ebner <f.ebner@proxmox.com>
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
Message-ID: <20250530151125.955508-7-f.ebner@proxmox.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>

4 files changed, 13 insertions, 12 deletions

diff --git a/block.c b/block.c
index 7207978..01144c8 100644
--- a/block.c
+++ b/block.c
@@ -1226,9 +1226,10 @@ static int bdrv_child_cb_inactivate(BdrvChild *child)
     return 0;
 }
 
-static bool bdrv_child_cb_change_aio_ctx(BdrvChild *child, AioContext *ctx,
-                                         GHashTable *visited, Transaction *tran,
-                                         Error **errp)
+static bool GRAPH_RDLOCK
+bdrv_child_cb_change_aio_ctx(BdrvChild *child, AioContext *ctx,
+                             GHashTable *visited, Transaction *tran,
+                             Error **errp)
 {
     BlockDriverState *bs = child->opaque;
     return bdrv_change_aio_context(bs, ctx, visited, tran, errp);
diff --git a/block/block-backend.c b/block/block-backend.c
index a402db1..6a6949e 100644
--- a/block/block-backend.c
+++ b/block/block-backend.c
@@ -136,9 +136,9 @@ static void blk_root_drained_end(BdrvChild *child);
 static void blk_root_change_media(BdrvChild *child, bool load);
 static void blk_root_resize(BdrvChild *child);
 
-static bool blk_root_change_aio_ctx(BdrvChild *child, AioContext *ctx,
-                                    GHashTable *visited, Transaction *tran,
-                                    Error **errp);
+static bool GRAPH_RDLOCK
+blk_root_change_aio_ctx(BdrvChild *child, AioContext *ctx, GHashTable *visited,
+                        Transaction *tran, Error **errp);
 
 static char *blk_root_get_parent_desc(BdrvChild *child)
 {
diff --git a/blockjob.c b/blockjob.c
index 32007f3..34185d7 100644
--- a/blockjob.c
+++ b/blockjob.c
@@ -144,9 +144,9 @@ static TransactionActionDrv change_child_job_context = {
     .clean = g_free,
 };
 
-static bool child_job_change_aio_ctx(BdrvChild *c, AioContext *ctx,
-                                     GHashTable *visited, Transaction *tran,
-                                     Error **errp)
+static bool GRAPH_RDLOCK
+child_job_change_aio_ctx(BdrvChild *c, AioContext *ctx, GHashTable *visited,
+                         Transaction *tran, Error **errp)
 {
     BlockJob *job = c->opaque;
     BdrvStateChildJobContext *s;
diff --git a/include/block/block_int-common.h b/include/block/block_int-common.h
index 2982dd3..37466c7 100644
--- a/include/block/block_int-common.h
+++ b/include/block/block_int-common.h
@@ -983,9 +983,9 @@ struct BdrvChildClass {
                            bool backing_mask_protocol,
                            Error **errp);
 
-    bool (*change_aio_ctx)(BdrvChild *child, AioContext *ctx,
-                           GHashTable *visited, Transaction *tran,
-                           Error **errp);
+    bool GRAPH_RDLOCK_PTR (*change_aio_ctx)(BdrvChild *child, AioContext *ctx,
+                                            GHashTable *visited,
+                                            Transaction *tran, Error **errp);
 
     /*
      * I/O API functions. These functions are thread-safe.