dm target:s introduce iterate devices fn

Add .iterate_devices to 'struct target_type' to allow a function to be
called for all devices in a DM target.  Implemented it for all targets
except those in dm-snap.c (origin and snapshot).

(The raid1 version number jumps to 1.12 because we originally reserved
1.1 to 1.11 for 'block_on_error' but ended up using 'handle_errors'
instead.)

Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
Cc: martin.petersen@oracle.com

1 files changed, 10 insertions, 1 deletions

diff --git a/drivers/md/dm-linear.c b/drivers/md/dm-linear.c
index ecbb17421da4..9184b6deb868 100644
--- a/drivers/md/dm-linear.c
+++ b/drivers/md/dm-linear.c
@@ -134,9 +134,17 @@ static int linear_merge(struct dm_target *ti, struct bvec_merge_data *bvm,
         return min(max_size, q->merge_bvec_fn(q, bvm, biovec));
 }
 
+static int linear_iterate_devices(struct dm_target *ti,
+                                  iterate_devices_callout_fn fn, void *data)
+{
+        struct linear_c *lc = ti->private;
+
+        return fn(ti, lc->dev, lc->start, data);
+}
+
 static struct target_type linear_target = {
         .name   = "linear",
-        .version= {1, 0, 3},
+        .version = {1, 1, 0},
         .module = THIS_MODULE,
         .ctr    = linear_ctr,
         .dtr    = linear_dtr,
@@ -144,6 +152,7 @@ static struct target_type linear_target = {
         .status = linear_status,
         .ioctl  = linear_ioctl,
         .merge  = linear_merge,
+        .iterate_devices = linear_iterate_devices,
 };
 
 int __init dm_linear_init(void)