orangefs: use list_for_each_entry_safe in purge_waiting_ops

commit 0afc0decf247f65b7aba666a76a0a68adf4bc435 upstream.

set_op_state_purged can delete the op.

Signed-off-by: Martin Brandenburg <martin@omnibond.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/fs/orangefs/waitqueue.c b/fs/orangefs/waitqueue.c
index abcfa3f..f61b008 100644
--- a/fs/orangefs/waitqueue.c
+++ b/fs/orangefs/waitqueue.c
@@ -28,10 +28,10 @@
  */
 void purge_waiting_ops(void)
 {
-	struct orangefs_kernel_op_s *op;
+	struct orangefs_kernel_op_s *op, *tmp;
 
 	spin_lock(&orangefs_request_list_lock);
-	list_for_each_entry(op, &orangefs_request_list, list) {
+	list_for_each_entry_safe(op, tmp, &orangefs_request_list, list) {
 		gossip_debug(GOSSIP_WAIT_DEBUG,
 			     "pvfs2-client-core: purging op tag %llu %s\n",
 			     llu(op->tag),