recipes-kernel/linux/linux-ti33x-psp-3.2/3.2.14/0093-SUNRPC-We-must-not-use-list_for_each_entry_safe-in-r.patch

   1 From cdc2a3f4e2494e413531264d3949ce6801123ad9 Mon Sep 17 00:00:00 2001
   2 From: Trond Myklebust <Trond.Myklebust@netapp.com>
   3 Date: Mon, 19 Mar 2012 13:39:35 -0400
   4 Subject: [PATCH 093/147] SUNRPC: We must not use list_for_each_entry_safe()
   5  in rpc_wake_up()
   6
   7 commit 540a0f7584169651f485e8ab67461fcb06934e38 upstream.
   8
   9 The problem is that for the case of priority queues, we
  10 have to assume that __rpc_remove_wait_queue_priority will move new
  11 elements from the tk_wait.links lists into the queue->tasks[] list.
  12 We therefore cannot use list_for_each_entry_safe() on queue->tasks[],
  13 since that will skip these new tasks that __rpc_remove_wait_queue_priority
  14 is adding.
  15
  16 Without this fix, rpc_wake_up and rpc_wake_up_status will both fail
  17 to wake up all functions on priority wait queues, which can result
  18 in some nasty hangs.
  19
  20 Reported-by: Andy Adamson <andros@netapp.com>
  21 Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
  22 Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
  23 ---
  24  net/sunrpc/sched.c |   15 +++++++++++----
  25  1 file changed, 11 insertions(+), 4 deletions(-)
  26
  27 diff --git a/net/sunrpc/sched.c b/net/sunrpc/sched.c
  28 index 00a1a2a..4e2b3b4 100644
  29 --- a/net/sunrpc/sched.c
  30 +++ b/net/sunrpc/sched.c
  31 @@ -500,14 +500,18 @@ EXPORT_SYMBOL_GPL(rpc_wake_up_next);
  32   */
  33  void rpc_wake_up(struct rpc_wait_queue *queue)
  34  {
  35 -       struct rpc_task *task, *next;
  36         struct list_head *head;
  37
  38         spin_lock_bh(&queue->lock);
  39         head = &queue->tasks[queue->maxpriority];
  40         for (;;) {
  41 -               list_for_each_entry_safe(task, next, head, u.tk_wait.list)
  42 +               while (!list_empty(head)) {
  43 +                       struct rpc_task *task;
  44 +                       task = list_first_entry(head,
  45 +                                       struct rpc_task,
  46 +                                       u.tk_wait.list);
  47                         rpc_wake_up_task_queue_locked(queue, task);
  48 +               }
  49                 if (head == &queue->tasks[0])
  50                         break;
  51                 head--;
  52 @@ -525,13 +529,16 @@ EXPORT_SYMBOL_GPL(rpc_wake_up);
  53   */
  54  void rpc_wake_up_status(struct rpc_wait_queue *queue, int status)
  55  {
  56 -       struct rpc_task *task, *next;
  57         struct list_head *head;
  58
  59         spin_lock_bh(&queue->lock);
  60         head = &queue->tasks[queue->maxpriority];
  61         for (;;) {
  62 -               list_for_each_entry_safe(task, next, head, u.tk_wait.list) {
  63 +               while (!list_empty(head)) {
  64 +                       struct rpc_task *task;
  65 +                       task = list_first_entry(head,
  66 +                                       struct rpc_task,
  67 +                                       u.tk_wait.list);
  68                         task->tk_status = status;
  69                         rpc_wake_up_task_queue_locked(queue, task);
  70                 }
  71 --
  72 1.7.9.4
  73