block: make bdrv_co_parent_cb_resize() a proper IO API function

In preparation for calling it via the bdrv_child_cb_resize() callback
that will be added by the next commit. Rename it to include the "_co_"
part while at it.

Signed-off-by: Fiona Ebner <f.ebner@proxmox.com>
Reviewed-by: Hanna Czenczek <hreitz@redhat.com>
Message-ID: <20250917115509.401015-3-f.ebner@proxmox.com>
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>

block/io.c

@@ -46,9 +46,6 @@
 /* Maximum read size for checking if data reads as zero, in bytes */
 #define MAX_ZERO_CHECK_BUFFER (128 * KiB)
 
-static void coroutine_fn GRAPH_RDLOCK
-bdrv_parent_cb_resize(BlockDriverState *bs);
-
 static int coroutine_fn bdrv_co_do_pwrite_zeroes(BlockDriverState *bs,
     int64_t offset, int64_t bytes, BdrvRequestFlags flags);
 
@@ -2038,7 +2035,7 @@ bdrv_co_write_req_finish(BdrvChild *child, int64_t offset, int64_t bytes,
          end_sector > bs->total_sectors) &&
         req->type != BDRV_TRACKED_DISCARD) {
         bs->total_sectors = end_sector;
-        bdrv_parent_cb_resize(bs);
+        bdrv_co_parent_cb_resize(bs);
         bdrv_dirty_bitmap_truncate(bs, end_sector << BDRV_SECTOR_BITS);
     }
     if (req->bytes) {
@@ -3570,11 +3567,11 @@ int coroutine_fn bdrv_co_copy_range(BdrvChild *src, int64_t src_offset,
                                    bytes, read_flags, write_flags);
 }
 
-static void coroutine_fn GRAPH_RDLOCK
-bdrv_parent_cb_resize(BlockDriverState *bs)
+void coroutine_fn bdrv_co_parent_cb_resize(BlockDriverState *bs)
 {
     BdrvChild *c;
 
+    IO_CODE();
     assert_bdrv_graph_readable();
 
     QLIST_FOREACH(c, &bs->parents, next_parent) {

include/block/block_int-io.h

@@ -191,4 +191,10 @@ void bdrv_bsc_invalidate_range(BlockDriverState *bs,
  */
 void bdrv_bsc_fill(BlockDriverState *bs, int64_t offset, int64_t bytes);
 
+/*
+ * Notify all parents that the size of the child changed.
+ */
+void coroutine_fn GRAPH_RDLOCK
+bdrv_co_parent_cb_resize(BlockDriverState *bs);
+
 #endif /* BLOCK_INT_IO_H */