bcache: Allocation kthread fixes

The alloc kthread should've been using try_to_freeze() - and also there
was the potential for the alloc kthread to get woken up after it had
shut down, which would have been bad.

Signed-off-by: Kent Overstreet <kmo@daterainc.com>

1 files changed, 8 insertions, 10 deletions

diff --git a/drivers/md/bcache/alloc.c b/drivers/md/bcache/alloc.c
index b54b73b9b2b7..e45f5575fd4d 100644
--- a/drivers/md/bcache/alloc.c
+++ b/drivers/md/bcache/alloc.c
@@ -63,6 +63,7 @@
 #include "bcache.h"
 #include "btree.h"
 
+#include <linux/freezer.h>
 #include <linux/kthread.h>
 #include <linux/random.h>
 #include <trace/events/bcache.h>
@@ -363,11 +364,10 @@ do {									\
                         break;                                          \
                                                                         \
                 mutex_unlock(&(ca)->set->bucket_lock);                  \
-                if (test_bit(CACHE_SET_STOPPING_2, &ca->set->flags)) {  \
-                        closure_put(&ca->set->cl);                      \
+                if (kthread_should_stop())                              \
                         return 0;                                       \
-                }                                                       \
                                                                         \
+                try_to_freeze();                                        \
                 schedule();                                             \
                 mutex_lock(&(ca)->set->bucket_lock);                    \
         }                                                               \
@@ -547,14 +547,12 @@ int bch_bucket_alloc_set(struct cache_set *c, unsigned watermark,
 
 int bch_cache_allocator_start(struct cache *ca)
 {
-        ca->alloc_thread = kthread_create(bch_allocator_thread,
-                                          ca, "bcache_allocator");
-        if (IS_ERR(ca->alloc_thread))
-                return PTR_ERR(ca->alloc_thread);
-
-        closure_get(&ca->set->cl);
-        wake_up_process(ca->alloc_thread);
+        struct task_struct *k = kthread_run(bch_allocator_thread,
+                                            ca, "bcache_allocator");
+        if (IS_ERR(k))
+                return PTR_ERR(k);
 
+        ca->alloc_thread = k;
         return 0;
 }