dm mpath: log device name

Make the mapped device structure accessible to hardware handlers so error
messages can include the device name.

Signed-off-by: Edward Goggin <egoggin@emc.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

3 files changed, 5 insertions, 0 deletions

diff --git a/drivers/md/dm-hw-handler.h b/drivers/md/dm-hw-handler.h
index 32eff28e4adc..e0832e6fcf36 100644
--- a/drivers/md/dm-hw-handler.h
+++ b/drivers/md/dm-hw-handler.h
@@ -16,6 +16,7 @@
 struct hw_handler_type;
 struct hw_handler {
         struct hw_handler_type *type;
+        struct mapped_device *md;
         void *context;
 };
 
diff --git a/drivers/md/dm-mpath.c b/drivers/md/dm-mpath.c
index 3aa013506967..de54b39e6ffe 100644
--- a/drivers/md/dm-mpath.c
+++ b/drivers/md/dm-mpath.c
@@ -668,6 +668,9 @@ static int parse_hw_handler(struct arg_set *as, struct multipath *m)
                 return -EINVAL;
         }
 
+        m->hw_handler.md = dm_table_get_md(ti->table);
+        dm_put(m->hw_handler.md);
+
         r = hwht->create(&m->hw_handler, hw_argc - 1, as->argv);
         if (r) {
                 dm_put_hw_handler(hwht);
diff --git a/drivers/md/dm.c b/drivers/md/dm.c
index 11a98df298ec..2717a355dc5b 100644
--- a/drivers/md/dm.c
+++ b/drivers/md/dm.c
@@ -1236,6 +1236,7 @@ void dm_put(struct mapped_device *md)
                 free_dev(md);
         }
 }
+EXPORT_SYMBOL_GPL(dm_put);
 
 /*
  * Process the deferred bios