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

7 files changed, 105 insertions, 6 deletions

diff --git a/drivers/md/dm-crypt.c b/drivers/md/dm-crypt.c
index 04db6c4004a..9933eb861c7 100644
--- a/drivers/md/dm-crypt.c
+++ b/drivers/md/dm-crypt.c
@@ -1313,9 +1313,17 @@ static int crypt_merge(struct dm_target *ti, struct bvec_merge_data *bvm,
         return min(max_size, q->merge_bvec_fn(q, bvm, biovec));
 }
 
+static int crypt_iterate_devices(struct dm_target *ti,
+                                 iterate_devices_callout_fn fn, void *data)
+{
+        struct crypt_config *cc = ti->private;
+
+        return fn(ti, cc->dev, cc->start, data);
+}
+
 static struct target_type crypt_target = {
         .name   = "crypt",
-        .version= {1, 6, 0},
+        .version = {1, 7, 0},
         .module = THIS_MODULE,
         .ctr    = crypt_ctr,
         .dtr    = crypt_dtr,
@@ -1326,6 +1334,7 @@ static struct target_type crypt_target = {
         .resume = crypt_resume,
         .message = crypt_message,
         .merge  = crypt_merge,
+        .iterate_devices = crypt_iterate_devices,
 };
 
 static int __init dm_crypt_init(void)
diff --git a/drivers/md/dm-delay.c b/drivers/md/dm-delay.c
index 8ad8a9044bb..4e5b843cd4d 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)
diff --git a/drivers/md/dm-linear.c b/drivers/md/dm-linear.c
index ecbb17421da..9184b6deb86 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)
diff --git a/drivers/md/dm-mpath.c b/drivers/md/dm-mpath.c
index 890c0e8ed13..f8aeaaa54af 100644
--- a/drivers/md/dm-mpath.c
+++ b/drivers/md/dm-mpath.c
@@ -1450,12 +1450,32 @@ static int multipath_ioctl(struct dm_target *ti, unsigned int cmd,
         return r ? : __blkdev_driver_ioctl(bdev, mode, cmd, arg);
 }
 
+static int multipath_iterate_devices(struct dm_target *ti,
+                                     iterate_devices_callout_fn fn, void *data)
+{
+        struct multipath *m = ti->private;
+        struct priority_group *pg;
+        struct pgpath *p;
+        int ret = 0;
+
+        list_for_each_entry(pg, &m->priority_groups, list) {
+                list_for_each_entry(p, &pg->pgpaths, list) {
+                        ret = fn(ti, p->path.dev, ti->begin, data);
+                        if (ret)
+                                goto out;
+                }
+        }
+
+out:
+        return ret;
+}
+
 /*-----------------------------------------------------------------
  * Module setup
  *---------------------------------------------------------------*/
 static struct target_type multipath_target = {
         .name = "multipath",
-        .version = {1, 0, 5},
+        .version = {1, 1, 0},
         .module = THIS_MODULE,
         .ctr = multipath_ctr,
         .dtr = multipath_dtr,
@@ -1466,6 +1486,7 @@ static struct target_type multipath_target = {
         .status = multipath_status,
         .message = multipath_message,
         .ioctl  = multipath_ioctl,
+        .iterate_devices = multipath_iterate_devices,
 };
 
 static int __init dm_multipath_init(void)
diff --git a/drivers/md/dm-raid1.c b/drivers/md/dm-raid1.c
index 076fbb4e967..ce8868c768c 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)
diff --git a/drivers/md/dm-stripe.c b/drivers/md/dm-stripe.c
index c64fe827a5f..b240e85ae39 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)
diff --git a/include/linux/device-mapper.h b/include/linux/device-mapper.h
index 236880c1dc3..deac3b4e5e1 100644
--- a/include/linux/device-mapper.h
+++ b/include/linux/device-mapper.h
@@ -11,6 +11,7 @@
 #include <linux/bio.h>
 #include <linux/blkdev.h>
 
+struct dm_dev;
 struct dm_target;
 struct dm_table;
 struct mapped_device;
@@ -81,6 +82,15 @@ typedef int (*dm_ioctl_fn) (struct dm_target *ti, unsigned int cmd,
 typedef int (*dm_merge_fn) (struct dm_target *ti, struct bvec_merge_data *bvm,
                             struct bio_vec *biovec, int max_size);
 
+typedef int (*iterate_devices_callout_fn) (struct dm_target *ti,
+                                           struct dm_dev *dev,
+                                           sector_t physical_start,
+                                           void *data);
+
+typedef int (*dm_iterate_devices_fn) (struct dm_target *ti,
+                                      iterate_devices_callout_fn fn,
+                                      void *data);
+
 /*
  * Returns:
  *    0: The target can handle the next I/O immediately.
@@ -139,6 +149,7 @@ struct target_type {
         dm_ioctl_fn ioctl;
         dm_merge_fn merge;
         dm_busy_fn busy;
+        dm_iterate_devices_fn iterate_devices;
 
         /* For internal device-mapper use. */
         struct list_head list;