diff options
Diffstat (limited to 'include/block')
| -rw-r--r-- | include/block/block.h | 8 |
1 files changed, 5 insertions, 3 deletions
diff --git a/include/block/block.h b/include/block/block.h index 127bdf3392..81fcaad5ac 100644 --- a/include/block/block.h +++ b/include/block/block.h @@ -72,9 +72,11 @@ typedef enum { BDRV_REQ_NO_FALLBACK = 0x100, /* - * BDRV_REQ_PREFETCH may be used only together with BDRV_REQ_COPY_ON_READ - * on read request and means that caller doesn't really need data to be - * written to qiov parameter which may be NULL. + * BDRV_REQ_PREFETCH makes sense only in the context of copy-on-read + * (i.e., together with the BDRV_REQ_COPY_ON_READ flag or when a COR + * filter is involved), in which case it signals that the COR operation + * need not read the data into memory (qiov) but only ensure they are + * copied to the top layer (i.e., that COR operation is done). */ BDRV_REQ_PREFETCH = 0x200, |