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, 4 insertions, 4 deletions

diff --git a/mm/page-writeback.c b/mm/page-writeback.c
index abc648f5de00..12c3d843ce93 100644
--- a/mm/page-writeback.c
+++ b/mm/page-writeback.c
@@ -315,7 +315,7 @@ int bdi_set_min_ratio(struct backing_dev_info *bdi, unsigned int min_ratio)
 {
         int ret = 0;
 
-        spin_lock(&bdi_lock);
+        spin_lock_bh(&bdi_lock);
         if (min_ratio > bdi->max_ratio) {
                 ret = -EINVAL;
         } else {
@@ -327,7 +327,7 @@ int bdi_set_min_ratio(struct backing_dev_info *bdi, unsigned int min_ratio)
                         ret = -EINVAL;
                 }
         }
-        spin_unlock(&bdi_lock);
+        spin_unlock_bh(&bdi_lock);
 
         return ret;
 }
@@ -339,14 +339,14 @@ int bdi_set_max_ratio(struct backing_dev_info *bdi, unsigned max_ratio)
         if (max_ratio > 100)
                 return -EINVAL;
 
-        spin_lock(&bdi_lock);
+        spin_lock_bh(&bdi_lock);
         if (bdi->min_ratio > max_ratio) {
                 ret = -EINVAL;
         } else {
                 bdi->max_ratio = max_ratio;
                 bdi->max_prop_frac = (PROP_FRAC_BASE * max_ratio) / 100;
         }
-        spin_unlock(&bdi_lock);
+        spin_unlock_bh(&bdi_lock);
 
         return ret;
 }