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, 19 insertions, 1 deletions

diff --git a/drivers/md/dm-delay.c b/drivers/md/dm-delay.c
index 8ad8a9044bbf..4e5b843cd4d7 100644
--- a/drivers/md/dm-delay.c
+++ b/drivers/md/dm-delay.c
@@ -318,9 +318,26 @@ static int delay_status(struct dm_target *ti, status_type_t type,
         return 0;
 }
 
+static int delay_iterate_devices(struct dm_target *ti,
+                                 iterate_devices_callout_fn fn, void *data)
+{
+        struct delay_c *dc = ti->private;
+        int ret = 0;
+
+        ret = fn(ti, dc->dev_read, dc->start_read, data);
+        if (ret)
+                goto out;
+
+        if (dc->dev_write)
+                ret = fn(ti, dc->dev_write, dc->start_write, data);
+
+out:
+        return ret;
+}
+
 static struct target_type delay_target = {
         .name        = "delay",
-        .version     = {1, 0, 2},
+        .version     = {1, 1, 0},
         .module      = THIS_MODULE,
         .ctr         = delay_ctr,
         .dtr         = delay_dtr,
@@ -328,6 +345,7 @@ static struct target_type delay_target = {
         .presuspend  = delay_presuspend,
         .resume      = delay_resume,
         .status      = delay_status,
+        .iterate_devices = delay_iterate_devices,
 };
 
 static int __init dm_delay_init(void)