ext4: Use rcu_barrier() on module unload.
The ext4 module uses rcu_call() thus it should use rcu_barrier()on
module unload.
The kmem cache ext4_pspace_cachep is sometimes free'ed using
call_rcu() callbacks. Thus, we must wait for completion of call_rcu()
before doing kmem_cache_destroy().
Signed-off-by: Jesper Dangaard Brouer <hawk@comx.dk>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
diff --git a/fs/ext4/mballoc.c b/fs/ext4/mballoc.c
index 4a45efa..2fcaf28 100644
--- a/fs/ext4/mballoc.c
+++ b/fs/ext4/mballoc.c
@@ -2909,7 +2909,11 @@
void exit_ext4_mballoc(void)
{
- /* XXX: synchronize_rcu(); */
+ /*
+ * Wait for completion of call_rcu()'s on ext4_pspace_cachep
+ * before destroying the slab cache.
+ */
+ rcu_barrier();
kmem_cache_destroy(ext4_pspace_cachep);
kmem_cache_destroy(ext4_ac_cachep);
kmem_cache_destroy(ext4_free_ext_cachep);