Document the current dm uevent API, as modified by this patchset. Signed-off-by: Andy Grover <agrover@xxxxxxxxxx> --- Documentation/device-mapper/dm-uevent.txt | 49 ++++++++++++++++++++++++++----- 1 file changed, 42 insertions(+), 7 deletions(-) diff --git a/Documentation/device-mapper/dm-uevent.txt b/Documentation/device-mapper/dm-uevent.txt index 07edbd85..0a5d909 100644 --- a/Documentation/device-mapper/dm-uevent.txt +++ b/Documentation/device-mapper/dm-uevent.txt @@ -1,18 +1,53 @@ The device-mapper uevent code adds the capability to device-mapper to create and send kobject uevents (uevents). Previously device-mapper events were only -available through the ioctl interface. The advantage of the uevents interface -is the event contains environment attributes providing increased context for +available through the ioctl interface. The advantages of the uevents interface +are the event contains environment attributes providing increased context for the event avoiding the need to query the state of the device-mapper device after -the event is received. +the event is received, and uevents are poll()-able in userspace, whereas the +ioctl event interface is not. -There are two functions currently for device-mapper events. The first function -listed creates the event and the second function sends the event(s). +There are five functions DM targets should use. -void dm_path_uevent(enum dm_uevent_type event_type, struct dm_target *ti, - const char *path, unsigned nr_valid_paths) +struct dm_uevent *dm_build_uevent(struct mapped_device *md, + struct dm_target *ti, + enum kobject_action action, + const char *dm_action) + +Construct a dm uevent with default DM variables attached(DM_TARGET, +DM_ACTION, DM_SEQNUM). + +int add_uevent_var(struct kobj_uevent_env *env, const char *format, ...) + +Optionally add event-specific data to the generated uevent. e.g. dm-mpath's +PATH_FAILED and PATH_REINSTATED uevents add path and number-of-remaining-paths +vars. + +void dm_uevent_add(struct mapped_device *md, struct list_head *elist) + +Hand off the uevent to the device's list of pending events. + +void dm_uevent_free(struct dm_uevent *event) + +Something went wrong, free the uevent instead of queueing it. + +void dm_table_event(struct dm_table *t) + +Triggers sending of queued uevents as well as waking up processes waiting on +the ioctl. + + +The device-mapper uevent code also supplies three functions for device-mapper core +to call: + +int dm_uevent_init(void) +void dm_uevent_exit(void) + +Setup and teardown. void dm_send_uevents(struct list_head *events, struct kobject *kobj) +Actually send the uevents (called indirectly from dm_table_event, above). + The variables added to the uevent environment are: -- 2.7.4 -- dm-devel mailing list dm-devel@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/dm-devel
