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, 17 insertions, 1 deletions

diff --git a/drivers/md/dm-stripe.c b/drivers/md/dm-stripe.c
index c64fe827a5f1..b240e85ae39a 100644
--- a/drivers/md/dm-stripe.c
+++ b/drivers/md/dm-stripe.c
@@ -313,15 +313,31 @@ static int stripe_end_io(struct dm_target *ti, struct bio *bio,
         return error;
 }
 
+static int stripe_iterate_devices(struct dm_target *ti,
+                                  iterate_devices_callout_fn fn, void *data)
+{
+        struct stripe_c *sc = ti->private;
+        int ret = 0;
+        unsigned i = 0;
+
+        do
+                ret = fn(ti, sc->stripe[i].dev,
+                         sc->stripe[i].physical_start, data);
+        while (!ret && ++i < sc->stripes);
+
+        return ret;
+}
+
 static struct target_type stripe_target = {
         .name   = "striped",
-        .version = {1, 1, 0},
+        .version = {1, 2, 0},
         .module = THIS_MODULE,
         .ctr    = stripe_ctr,
         .dtr    = stripe_dtr,
         .map    = stripe_map,
         .end_io = stripe_end_io,
         .status = stripe_status,
+        .iterate_devices = stripe_iterate_devices,
 };
 
 int __init dm_stripe_init(void)