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, 16 insertions, 1 deletions

diff --git a/drivers/md/dm-raid1.c b/drivers/md/dm-raid1.c
index 076fbb4e967a..ce8868c768cc 100644
--- a/drivers/md/dm-raid1.c
+++ b/drivers/md/dm-raid1.c
@@ -1283,9 +1283,23 @@ static int mirror_status(struct dm_target *ti, status_type_t type,
         return 0;
 }
 
+static int mirror_iterate_devices(struct dm_target *ti,
+                                  iterate_devices_callout_fn fn, void *data)
+{
+        struct mirror_set *ms = ti->private;
+        int ret = 0;
+        unsigned i;
+
+        for (i = 0; !ret && i < ms->nr_mirrors; i++)
+                ret = fn(ti, ms->mirror[i].dev,
+                         ms->mirror[i].offset, data);
+
+        return ret;
+}
+
 static struct target_type mirror_target = {
         .name    = "mirror",
-        .version = {1, 0, 20},
+        .version = {1, 12, 0},
         .module  = THIS_MODULE,
         .ctr     = mirror_ctr,
         .dtr     = mirror_dtr,
@@ -1295,6 +1309,7 @@ static struct target_type mirror_target = {
         .postsuspend = mirror_postsuspend,
         .resume  = mirror_resume,
         .status  = mirror_status,
+        .iterate_devices = mirror_iterate_devices,
 };
 
 static int __init dm_mirror_init(void)