dm thin: initialize dm_thin_new_mapping returned by get_next_mapping

As additional members are added to the dm_thin_new_mapping structure
care should be taken to make sure they get initialized before use.

Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Acked-by: Joe Thornber <ejt@redhat.com>
Cc: stable@vger.kernel.org

1 files changed, 6 insertions, 11 deletions

diff --git a/drivers/md/dm-thin.c b/drivers/md/dm-thin.c
index ee29037ffc2e..da65febdb6c4 100644
--- a/drivers/md/dm-thin.c
+++ b/drivers/md/dm-thin.c
@@ -751,13 +751,17 @@ static int ensure_next_mapping(struct pool *pool)
 
 static struct dm_thin_new_mapping *get_next_mapping(struct pool *pool)
 {
-        struct dm_thin_new_mapping *r = pool->next_mapping;
+        struct dm_thin_new_mapping *m = pool->next_mapping;
 
         BUG_ON(!pool->next_mapping);
 
+        memset(m, 0, sizeof(struct dm_thin_new_mapping));
+        INIT_LIST_HEAD(&m->list);
+        m->bio = NULL;
+
         pool->next_mapping = NULL;
 
-        return r;
+        return m;
 }
 
 static void schedule_copy(struct thin_c *tc, dm_block_t virt_block,
@@ -769,15 +773,10 @@ static void schedule_copy(struct thin_c *tc, dm_block_t virt_block,
         struct pool *pool = tc->pool;
         struct dm_thin_new_mapping *m = get_next_mapping(pool);
 
-        INIT_LIST_HEAD(&m->list);
-        m->quiesced = 0;
-        m->prepared = 0;
         m->tc = tc;
         m->virt_block = virt_block;
         m->data_block = data_dest;
         m->cell = cell;
-        m->err = 0;
-        m->bio = NULL;
 
         if (!dm_deferred_set_add_work(pool->shared_read_ds, &m->list))
                 m->quiesced = 1;
@@ -840,15 +839,12 @@ static void schedule_zero(struct thin_c *tc, dm_block_t virt_block,
         struct pool *pool = tc->pool;
         struct dm_thin_new_mapping *m = get_next_mapping(pool);
 
-        INIT_LIST_HEAD(&m->list);
         m->quiesced = 1;
         m->prepared = 0;
         m->tc = tc;
         m->virt_block = virt_block;
         m->data_block = data_block;
         m->cell = cell;
-        m->err = 0;
-        m->bio = NULL;
 
         /*
          * If the whole block of data is being overwritten or we are not
@@ -1045,7 +1041,6 @@ static void process_discard(struct thin_c *tc, struct bio *bio)
                         m->data_block = lookup_result.block;
                         m->cell = cell;
                         m->cell2 = cell2;
-                        m->err = 0;
                         m->bio = bio;
 
                         if (!dm_deferred_set_add_work(pool->all_io_ds, &m->list)) {