[PATCH] dm table: store md

Store an up-pointer to the owning struct mapped_device in every table when it
is created.

Access it with:
  struct mapped_device *dm_table_get_md(struct dm_table *t)

Tables linked to md must be destroyed before the md itself.

Signed-off-by: Mike Anderson <andmike@us.ibm.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

1 files changed, 12 insertions, 1 deletions

diff --git a/drivers/md/dm-table.c b/drivers/md/dm-table.c
index 9558a4acec12..84f4594afd3c 100644
--- a/drivers/md/dm-table.c
+++ b/drivers/md/dm-table.c
@@ -22,6 +22,7 @@
 #define CHILDREN_PER_NODE (KEYS_PER_NODE + 1)
 
 struct dm_table {
+        struct mapped_device *md;
         atomic_t holders;
 
         /* btree table */
@@ -206,7 +207,8 @@ static int alloc_targets(struct dm_table *t, unsigned int num)
         return 0;
 }
 
-int dm_table_create(struct dm_table **result, int mode, unsigned num_targets)
+int dm_table_create(struct dm_table **result, int mode,
+                    unsigned num_targets, struct mapped_device *md)
 {
         struct dm_table *t = kmalloc(sizeof(*t), GFP_KERNEL);
 
@@ -229,6 +231,7 @@ int dm_table_create(struct dm_table **result, int mode, unsigned num_targets)
         }
 
         t->mode = mode;
+        t->md = md;
         *result = t;
         return 0;
 }
@@ -952,12 +955,20 @@ int dm_table_flush_all(struct dm_table *t)
         return ret;
 }
 
+struct mapped_device *dm_table_get_md(struct dm_table *t)
+{
+        dm_get(t->md);
+
+        return t->md;
+}
+
 EXPORT_SYMBOL(dm_vcalloc);
 EXPORT_SYMBOL(dm_get_device);
 EXPORT_SYMBOL(dm_put_device);
 EXPORT_SYMBOL(dm_table_event);
 EXPORT_SYMBOL(dm_table_get_size);
 EXPORT_SYMBOL(dm_table_get_mode);
+EXPORT_SYMBOL(dm_table_get_md);
 EXPORT_SYMBOL(dm_table_put);
 EXPORT_SYMBOL(dm_table_get);
 EXPORT_SYMBOL(dm_table_unplug_all);