rcu/kvfree: Refactor kvfree_rcu_queue_batch()

Improve readability of kvfree_rcu_queue_batch() function
in away that, after a first batch queuing, the loop is break
and success value is returned to a caller.

There is no reason to loop and check batches further as all
outstanding objects have already been picked and attached to
a certain batch to complete an offloading.

Fixes: 2b55d6a42d14 ("rcu/kvfree: Add kvfree_rcu_barrier() API")
Suggested-by: Linus Torvalds <torvalds@linux-foundation.org>
Closes: https://lore.kernel.org/lkml/ZvWUt2oyXRsvJRNc@pc636/T/
Signed-off-by: Uladzislau Rezki (Sony) <urezki@gmail.com>
Signed-off-by: Vlastimil Babka <vbabka@suse.cz>

diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c
index a60616e69b66326c6fb68f0251653b11c7003819..b1f883fcd9185a5e22c10102d1024c40688f57fb 100644 (file)
--- a/kernel/rcu/tree.c
+++ b/kernel/rcu/tree.c
@@ -3607,11 +3607,12 @@ kvfree_rcu_queue_batch(struct kfree_rcu_cpu *krcp)
                        }
 
                        // One work is per one batch, so there are three
-                       // "free channels", the batch can handle. It can
-                       // be that the work is in the pending state when
-                       // channels have been detached following by each
-                       // other.
+                       // "free channels", the batch can handle. Break
+                       // the loop since it is done with this CPU thus
+                       // queuing an RCU work is _always_ success here.
                        queued = queue_rcu_work(system_unbound_wq, &krwp->rcu_work);
+                       WARN_ON_ONCE(!queued);
+                       break;
                }
        }