drm/fb_helper: Fix potential NULL pointer dereference

[platform/kernel/linux-rpi.git] / drivers / md / dm-bufio.c

diff --git a/drivers/md/dm-bufio.c b/drivers/md/dm-bufio.c
index cc06a1e..651ca79 100644 (file)
--- a/drivers/md/dm-bufio.c
+++ b/drivers/md/dm-bufio.c
@@ -280,9 +280,7 @@ static void __cache_size_refresh(void)
        BUG_ON(!mutex_is_locked(&dm_bufio_clients_lock));
        BUG_ON(dm_bufio_client_count < 0);
 
-       dm_bufio_cache_size_latch = dm_bufio_cache_size;
-
-       barrier();
+       dm_bufio_cache_size_latch = ACCESS_ONCE(dm_bufio_cache_size);
 
        /*
         * Use default if set to 0 and report the actual cache size used.
@@ -441,8 +439,7 @@ static void __relink_lru(struct dm_buffer *b, int dirty)
        c->n_buffers[b->list_mode]--;
        c->n_buffers[dirty]++;
        b->list_mode = dirty;
-       list_del(&b->lru_list);
-       list_add(&b->lru_list, &c->lru[dirty]);
+       list_move(&b->lru_list, &c->lru[dirty]);
 }
 
 /*----------------------------------------------------------------
@@ -813,7 +810,7 @@ static void __get_memory_limit(struct dm_bufio_client *c,
 {
        unsigned long buffers;
 
-       if (dm_bufio_cache_size != dm_bufio_cache_size_latch) {
+       if (ACCESS_ONCE(dm_bufio_cache_size) != dm_bufio_cache_size_latch) {
                mutex_lock(&dm_bufio_clients_lock);
                __cache_size_refresh();
                mutex_unlock(&dm_bufio_clients_lock);
@@ -1591,11 +1588,9 @@ EXPORT_SYMBOL_GPL(dm_bufio_client_destroy);
 
 static void cleanup_old_buffers(void)
 {
-       unsigned long max_age = dm_bufio_max_age;
+       unsigned long max_age = ACCESS_ONCE(dm_bufio_max_age);
        struct dm_bufio_client *c;
 
-       barrier();
-
        if (max_age > ULONG_MAX / HZ)
                max_age = ULONG_MAX / HZ;