block: Add blk_next_root_bs()
This function iterates over all BDSs attached to a BB. We are going to
need it when rewriting bdrv_next() so it no longer uses bdrv_states.
Signed-off-by: Max Reitz <mreitz@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
diff --git a/block/block-backend.c b/block/block-backend.c
index b3c3d39..7818aa2 100644
--- a/block/block-backend.c
+++ b/block/block-backend.c
@@ -250,6 +250,30 @@
}
/*
+ * Iterates over all BlockDriverStates which are attached to a BlockBackend.
+ * This function is for use by bdrv_next().
+ *
+ * @bs must be NULL or a BDS that is attached to a BB.
+ */
+BlockDriverState *blk_next_root_bs(BlockDriverState *bs)
+{
+ BlockBackend *blk;
+
+ if (bs) {
+ assert(bs->blk);
+ blk = bs->blk;
+ } else {
+ blk = NULL;
+ }
+
+ do {
+ blk = blk_all_next(blk);
+ } while (blk && !blk->bs);
+
+ return blk ? blk->bs : NULL;
+}
+
+/*
* Add a BlockBackend into the list of backends referenced by the monitor, with
* the given @name acting as the handle for the monitor.
* Strictly for use by blockdev.c.
diff --git a/include/sysemu/block-backend.h b/include/sysemu/block-backend.h
index 60c4b07..d839bff 100644
--- a/include/sysemu/block-backend.h
+++ b/include/sysemu/block-backend.h
@@ -70,6 +70,7 @@
const char *blk_name(BlockBackend *blk);
BlockBackend *blk_by_name(const char *name);
BlockBackend *blk_next(BlockBackend *blk);
+BlockDriverState *blk_next_root_bs(BlockDriverState *bs);
bool monitor_add_blk(BlockBackend *blk, const char *name, Error **errp);
void monitor_remove_blk(BlockBackend *blk);
