diff options
Diffstat (limited to 'include/uapi/linux/dm-log-userspace.h')
| -rw-r--r-- | include/uapi/linux/dm-log-userspace.h | 20 |
1 files changed, 17 insertions, 3 deletions
diff --git a/include/uapi/linux/dm-log-userspace.h b/include/uapi/linux/dm-log-userspace.h index 0678c2adc42..0fa0d9ef06a 100644 --- a/include/uapi/linux/dm-log-userspace.h +++ b/include/uapi/linux/dm-log-userspace.h @@ -201,11 +201,18 @@ * int (*flush)(struct dm_dirty_log *log); * * Payload-to-userspace: - * None. + * If the 'integrated_flush' directive is present in the constructor + * table, the payload is as same as DM_ULOG_MARK_REGION: + * uint64_t [] - region(s) to mark + * else + * None * Payload-to-kernel: * None. * - * No incoming or outgoing payload. Simply flush log state to disk. + * If the 'integrated_flush' option was used during the creation of the + * log, mark region requests are carried as payload in the flush request. + * Piggybacking the mark requests in this way allows for fewer communications + * between kernel and userspace. * * When the request has been processed, user-space must return the * dm_ulog_request to the kernel - setting the 'error' field and clearing @@ -385,8 +392,15 @@ * version 2: DM_ULOG_CTR allowed to return a string containing a * device name that is to be registered with DM via * 'dm_get_device'. + * version 3: DM_ULOG_FLUSH is capable of carrying payload for marking + * regions. This "integrated flush" reduces the number of + * requests between the kernel and userspace by effectively + * merging 'mark' and 'flush' requests. A constructor table + * argument ('integrated_flush') is required to turn this + * feature on, so it is backwards compatible with older + * userspace versions. */ -#define DM_ULOG_REQUEST_VERSION 2 +#define DM_ULOG_REQUEST_VERSION 3 struct dm_ulog_request { /* |