This function tries to request, if not granted yet, for the given permissions.
Signed-off-by: Fam Zheng <f...@redhat.com> --- block/block-backend.c | 12 ++++++++++++ include/sysemu/block-backend.h | 1 + 2 files changed, 13 insertions(+) diff --git a/block/block-backend.c b/block/block-backend.c index 5742c09..5d17404 100644 --- a/block/block-backend.c +++ b/block/block-backend.c @@ -595,6 +595,18 @@ void blk_get_perm(BlockBackend *blk, uint64_t *perm, uint64_t *shared_perm) *shared_perm = blk->shared_perm; } +int blk_request_perm(BlockBackend *blk, uint64_t perm, Error **errp) +{ + uint64_t blk_perm, shared_perm; + + blk_get_perm(blk, &blk_perm, &shared_perm); + if ((blk_perm & perm) == perm) { + return 0; + } + blk_perm |= perm; + return blk_set_perm(blk, blk_perm, shared_perm, errp); +} + static int blk_do_attach_dev(BlockBackend *blk, void *dev) { if (blk->dev) { diff --git a/include/sysemu/block-backend.h b/include/sysemu/block-backend.h index 096c17f..016632e 100644 --- a/include/sysemu/block-backend.h +++ b/include/sysemu/block-backend.h @@ -108,6 +108,7 @@ bool bdrv_is_root_node(BlockDriverState *bs); int blk_set_perm(BlockBackend *blk, uint64_t perm, uint64_t shared_perm, Error **errp); void blk_get_perm(BlockBackend *blk, uint64_t *perm, uint64_t *shared_perm); +int blk_request_perm(BlockBackend *blk, uint64_t perm, Error **errp); void blk_set_allow_write_beyond_eof(BlockBackend *blk, bool allow); void blk_iostatus_enable(BlockBackend *blk); -- 2.9.3