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>

1 files changed, 4 insertions, 0 deletions

diff --git a/drivers/md/dm-table.c b/drivers/md/dm-table.c
index c90e662d2802..1a6cb3c7822e 100644
--- a/drivers/md/dm-table.c
+++ b/drivers/md/dm-table.c
@@ -1007,6 +1007,10 @@ int dm_calculate_queue_limits(struct dm_table *table,
                 ti->type->iterate_devices(ti, dm_set_device_limits,
                                           &ti_limits);
 
+                /* Set I/O hints portion of queue limits */
+                if (ti->type->io_hints)
+                        ti->type->io_hints(ti, &ti_limits);
+
                 /*
                  * Check each device area is consistent with the target's
                  * overall queue limits.