percpu: fix locking regression in the failure path of pcpu_alloc()

While updating locking, b38d08f3181c ("percpu: restructure locking")
broke pcpu_create_chunk() creation path in pcpu_alloc().  It returns
without releasing pcpu_alloc_mutex.  Fix it.

Signed-off-by: Tejun Heo <tj@kernel.org>
Reported-by: Julia Lawall <julia.lawall@lip6.fr>

diff --git a/mm/percpu.c b/mm/percpu.c
index 867efd3..af3dd27 100644 (file)
--- a/mm/percpu.c
+++ b/mm/percpu.c
@@ -974,6 +974,7 @@ restart:
        if (list_empty(&pcpu_slot[pcpu_nr_slots - 1])) {
                chunk = pcpu_create_chunk();
                if (!chunk) {
+                       mutex_unlock(&pcpu_alloc_mutex);
                        err = "failed to allocate new chunk";
                        goto fail;
                }