[PATCH V2] libcfs: Fix a sleep-in-atomic bug in cfs_wi_exit

[Jia-Ju Bai]

The driver may sleep under a spin lock, and the function call path is:
cfs_wi_exit (acquire the lock by spin_lock)
  LASSERT
    lbug_with_loc
      libcfs_debug_dumplog
        schedule and kthread_run --> may sleep

To fix it, all "LASSERT" is placed out of the spin_lock and spin_unlock.

Signed-off-by: Jia-Ju Bai <baijiaju1...@163.com>
---
 drivers/staging/lustre/lnet/libcfs/workitem.c |   13 +++++++------
 1 file changed, 7 insertions(+), 6 deletions(-)

diff --git a/drivers/staging/lustre/lnet/libcfs/workitem.c 
b/drivers/staging/lustre/lnet/libcfs/workitem.c
index dbc2a9b..928d06d 100644
--- a/drivers/staging/lustre/lnet/libcfs/workitem.c
+++ b/drivers/staging/lustre/lnet/libcfs/workitem.c
@@ -111,22 +111,23 @@ struct cfs_wi_sched {
 {
        LASSERT(!in_interrupt()); /* because we use plain spinlock */
        LASSERT(!sched->ws_stopping);
+       LASSERT(wi->wi_running);
+       if (wi->wi_scheduled) {
+               LASSERT(!list_empty(&wi->wi_list));
+               LASSERT(sched->ws_nscheduled > 0);
+       }
 
        spin_lock(&sched->ws_lock);
 
-       LASSERT(wi->wi_running);
        if (wi->wi_scheduled) { /* cancel pending schedules */
-               LASSERT(!list_empty(&wi->wi_list));
                list_del_init(&wi->wi_list);
-
-               LASSERT(sched->ws_nscheduled > 0);
                sched->ws_nscheduled--;
        }
 
-       LASSERT(list_empty(&wi->wi_list));
-
        wi->wi_scheduled = 1; /* LBUG future schedule attempts */
        spin_unlock(&sched->ws_lock);
+
+       LASSERT(list_empty(&wi->wi_list));
 }
 EXPORT_SYMBOL(cfs_wi_exit);
 
-- 
1.7.9.5