writeback: use RCU to protect bdi_list

Now that bdi_writeback_all() no longer handles integrity writeback,
it doesn't have to block anymore. This means that we can switch
bdi_list reader side protection to RCU.

Signed-off-by: Jens Axboe <jens.axboe@oracle.com>

1 files changed, 3 insertions, 3 deletions

diff --git a/fs/fs-writeback.c b/fs/fs-writeback.c
index 14f06b459197..f8cd7a97f5b7 100644
--- a/fs/fs-writeback.c
+++ b/fs/fs-writeback.c
@@ -868,16 +868,16 @@ static void bdi_writeback_all(struct writeback_control *wbc)
 
         WARN_ON(wbc->sync_mode == WB_SYNC_ALL);
 
-        spin_lock(&bdi_lock);
+        rcu_read_lock();
 
-        list_for_each_entry(bdi, &bdi_list, bdi_list) {
+        list_for_each_entry_rcu(bdi, &bdi_list, bdi_list) {
                 if (!bdi_has_dirty_io(bdi))
                         continue;
 
                 bdi_alloc_queue_work(bdi, wbc);
         }
 
-        spin_unlock(&bdi_lock);
+        rcu_read_unlock();
 }
 
 /*