dm stripe: expose correct io hints
Set sensible I/O hints for striped DM devices in the topology
infrastructure added for 2.6.31 for userspace tools to
obtain via sysfs.
Add .io_hints to 'struct target_type' to allow the I/O hints portion
(io_min and io_opt) of the 'struct queue_limits' to be set by each
target and implement this for dm-stripe.
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
diff --git a/include/linux/device-mapper.h b/include/linux/device-mapper.h
index 655e772..df7607e 100644
--- a/include/linux/device-mapper.h
+++ b/include/linux/device-mapper.h
@@ -91,6 +91,9 @@
iterate_devices_callout_fn fn,
void *data);
+typedef void (*dm_io_hints_fn) (struct dm_target *ti,
+ struct queue_limits *limits);
+
/*
* Returns:
* 0: The target can handle the next I/O immediately.
@@ -151,6 +154,7 @@
dm_merge_fn merge;
dm_busy_fn busy;
dm_iterate_devices_fn iterate_devices;
+ dm_io_hints_fn io_hints;
/* For internal device-mapper use. */
struct list_head list;