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>
diff --git a/drivers/md/bcache/alloc.c b/drivers/md/bcache/alloc.c
index b54b73b..e45f557 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 @@
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_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);
+ struct task_struct *k = kthread_run(bch_allocator_thread,
+ ca, "bcache_allocator");
+ if (IS_ERR(k))
+ return PTR_ERR(k);
- closure_get(&ca->set->cl);
- wake_up_process(ca->alloc_thread);
-
+ ca->alloc_thread = k;
return 0;
}
diff --git a/drivers/md/bcache/bcache.h b/drivers/md/bcache/bcache.h
index 68f1ded..b39f6f0 100644
--- a/drivers/md/bcache/bcache.h
+++ b/drivers/md/bcache/bcache.h
@@ -664,13 +664,9 @@
* CACHE_SET_STOPPING always gets set first when we're closing down a cache set;
* we'll continue to run normally for awhile with CACHE_SET_STOPPING set (i.e.
* flushing dirty data).
- *
- * CACHE_SET_STOPPING_2 gets set at the last phase, when it's time to shut down
- * the allocation thread.
*/
#define CACHE_SET_UNREGISTERING 0
#define CACHE_SET_STOPPING 1
-#define CACHE_SET_STOPPING_2 2
struct cache_set {
struct closure cl;
diff --git a/drivers/md/bcache/super.c b/drivers/md/bcache/super.c
index f6a6217..547c4c5 100644
--- a/drivers/md/bcache/super.c
+++ b/drivers/md/bcache/super.c
@@ -16,6 +16,7 @@
#include <linux/buffer_head.h>
#include <linux/debugfs.h>
#include <linux/genhd.h>
+#include <linux/kthread.h>
#include <linux/module.h>
#include <linux/random.h>
#include <linux/reboot.h>
@@ -1329,11 +1330,9 @@
static void cache_set_flush(struct closure *cl)
{
struct cache_set *c = container_of(cl, struct cache_set, caching);
+ struct cache *ca;
struct btree *b;
-
- /* Shut down allocator threads */
- set_bit(CACHE_SET_STOPPING_2, &c->flags);
- wake_up_allocators(c);
+ unsigned i;
bch_cache_accounting_destroy(&c->accounting);
@@ -1348,6 +1347,10 @@
if (btree_node_dirty(b))
bch_btree_node_write(b, NULL);
+ for_each_cache(ca, c, i)
+ if (ca->alloc_thread)
+ kthread_stop(ca->alloc_thread);
+
closure_return(cl);
}