dm thin: simplify pool_is_congested

The pool is congested if the pool is in PM_OUT_OF_DATA_SPACE mode.  This
is more explicit/clear/efficient than inferring whether or not the pool
is congested by checking if retry_on_resume_list is empty.

Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Acked-by: Joe Thornber <ejt@redhat.com>

1 files changed, 5 insertions, 11 deletions

diff --git a/drivers/md/dm-thin.c b/drivers/md/dm-thin.c
index 60cc50685c14..af871fd48eb4 100644
--- a/drivers/md/dm-thin.c
+++ b/drivers/md/dm-thin.c
@@ -1757,20 +1757,14 @@ static int thin_bio_map(struct dm_target *ti, struct bio *bio)
 
 static int pool_is_congested(struct dm_target_callbacks *cb, int bdi_bits)
 {
-        int r;
-        unsigned long flags;
         struct pool_c *pt = container_of(cb, struct pool_c, callbacks);
+        struct request_queue *q;
 
-        spin_lock_irqsave(&pt->pool->lock, flags);
-        r = !bio_list_empty(&pt->pool->retry_on_resume_list);
-        spin_unlock_irqrestore(&pt->pool->lock, flags);
+        if (get_pool_mode(pt->pool) == PM_OUT_OF_DATA_SPACE)
+                return 1;
 
-        if (!r) {
-                struct request_queue *q = bdev_get_queue(pt->data_dev->bdev);
-                r = bdi_congested(&q->backing_dev_info, bdi_bits);
-        }
-
-        return r;
+        q = bdev_get_queue(pt->data_dev->bdev);
+        return bdi_congested(&q->backing_dev_info, bdi_bits);
 }
 
 static void __requeue_bios(struct pool *pool)