diff options
| -rw-r--r-- | include/block/block_int.h | 9 |
1 files changed, 9 insertions, 0 deletions
diff --git a/include/block/block_int.h b/include/block/block_int.h index 437d746733..5451f89b8d 100644 --- a/include/block/block_int.h +++ b/include/block/block_int.h @@ -348,6 +348,15 @@ struct BlockDriver { * clamped to bdrv_getlength() and aligned to request_alignment, * as well as non-NULL pnum, map, and file; in turn, the driver * must return an error or set pnum to an aligned non-zero value. + * + * Note that @bytes is just a hint on how big of a region the + * caller wants to inspect. It is not a limit on *pnum. + * Implementations are free to return larger values of *pnum if + * doing so does not incur a performance penalty. + * + * block/io.c's bdrv_co_block_status() will utilize an unclamped + * *pnum value for the block-status cache on protocol nodes, prior + * to clamping *pnum for return to its caller. */ int coroutine_fn (*bdrv_co_block_status)(BlockDriverState *bs, bool want_zero, int64_t offset, int64_t bytes, int64_t *pnum, |