meta-agl-jailhouse/recipes-kernel/linux/linux/0015-ivshmem-net-fix-race-in-state-machine.patch

   1 From 1349a457e5e33580fb26afab087e6b932b1a4372 Mon Sep 17 00:00:00 2001
   2 From: Mans Rullgard <mans@mansr.com>
   3 Date: Thu, 24 Nov 2016 18:46:41 +0000
   4 Subject: [PATCH 15/32] ivshmem-net: fix race in state machine
   5
   6 ---
   7  drivers/net/ivshmem-net.c | 60 ++++++++++++++++++++++++-----------------------
   8  1 file changed, 31 insertions(+), 29 deletions(-)
   9
  10 diff --git a/drivers/net/ivshmem-net.c b/drivers/net/ivshmem-net.c
  11 index a535cb71adde..acd00e47acd7 100644
  12 --- a/drivers/net/ivshmem-net.c
  13 +++ b/drivers/net/ivshmem-net.c
  14 @@ -36,6 +36,8 @@
  15  #define IVSHM_NET_STATE_READY  2
  16  #define IVSHM_NET_STATE_RUN    3
  17
  18 +#define IVSHM_NET_FLAG_RUN     0
  19 +
  20  #define IVSHM_NET_MTU_MIN 256
  21  #define IVSHM_NET_MTU_MAX 65535
  22  #define IVSHM_NET_MTU_DEF 16384
  23 @@ -96,6 +98,8 @@ struct ivshm_net {
  24         u32 lstate;
  25         u32 rstate;
  26
  27 +       unsigned long flags;
  28 +
  29         struct workqueue_struct *state_wq;
  30         struct work_struct state_work;
  31
  32 @@ -529,12 +533,32 @@ static void ivshm_net_run(struct net_device *ndev)
  33  {
  34         struct ivshm_net *in = netdev_priv(ndev);
  35
  36 +       if (in->lstate < IVSHM_NET_STATE_READY)
  37 +               return;
  38 +
  39 +       if (!netif_running(ndev))
  40 +               return;
  41 +
  42 +       if (test_and_set_bit(IVSHM_NET_FLAG_RUN, &in->flags))
  43 +               return;
  44 +
  45         netif_start_queue(ndev);
  46         napi_enable(&in->napi);
  47         napi_schedule(&in->napi);
  48         ivshm_net_set_state(in, IVSHM_NET_STATE_RUN);
  49  }
  50
  51 +static void ivshm_net_do_stop(struct net_device *ndev)
  52 +{
  53 +       struct ivshm_net *in = netdev_priv(ndev);
  54 +
  55 +       if (!test_and_clear_bit(IVSHM_NET_FLAG_RUN, &in->flags))
  56 +               return;
  57 +
  58 +       netif_stop_queue(ndev);
  59 +       napi_disable(&in->napi);
  60 +}
  61 +
  62  static void ivshm_net_state_change(struct work_struct *work)
  63  {
  64         struct ivshm_net *in = container_of(work, struct ivshm_net, state_work);
  65 @@ -560,21 +584,13 @@ static void ivshm_net_state_change(struct work_struct *work)
  66                 break;
  67
  68         case IVSHM_NET_STATE_READY:
  69 +       case IVSHM_NET_STATE_RUN:
  70                 if (rstate >= IVSHM_NET_STATE_READY) {
  71                         netif_carrier_on(ndev);
  72 -                       if (ndev->flags & IFF_UP)
  73 -                               ivshm_net_run(ndev);
  74 +                       ivshm_net_run(ndev);
  75                 } else {
  76                         netif_carrier_off(ndev);
  77 -                       ivshm_net_set_state(in, IVSHM_NET_STATE_RESET);
  78 -               }
  79 -               break;
  80 -
  81 -       case IVSHM_NET_STATE_RUN:
  82 -               if (rstate < IVSHM_NET_STATE_READY) {
  83 -                       netif_stop_queue(ndev);
  84 -                       napi_disable(&in->napi);
  85 -                       netif_carrier_off(ndev);
  86 +                       ivshm_net_do_stop(ndev);
  87                         ivshm_net_set_state(in, IVSHM_NET_STATE_RESET);
  88                 }
  89                 break;
  90 @@ -584,18 +600,13 @@ static void ivshm_net_state_change(struct work_struct *work)
  91         WRITE_ONCE(in->rstate, rstate);
  92  }
  93
  94 -static bool ivshm_net_check_state(struct net_device *ndev)
  95 +static void ivshm_net_check_state(struct net_device *ndev)
  96  {
  97         struct ivshm_net *in = netdev_priv(ndev);
  98         u32 rstate = readl(&in->ivshm_regs->rstate);
  99
 100 -       if (rstate != READ_ONCE(in->rstate) ||
 101 -           in->lstate != IVSHM_NET_STATE_RUN) {
 102 +       if (rstate != in->rstate || !test_bit(IVSHM_NET_FLAG_RUN, &in->flags))
 103                 queue_work(in->state_wq, &in->state_work);
 104 -               return false;
 105 -       }
 106 -
 107 -       return true;
 108  }
 109
 110  static irqreturn_t ivshm_net_int(int irq, void *data)
 111 @@ -617,24 +628,15 @@ static int ivshm_net_open(struct net_device *ndev)
 112
 113         netdev_reset_queue(ndev);
 114         ndev->operstate = IF_OPER_UP;
 115 -
 116 -       if (in->lstate == IVSHM_NET_STATE_READY)
 117 -               ivshm_net_run(ndev);
 118 +       ivshm_net_run(ndev);
 119
 120         return 0;
 121  }
 122
 123  static int ivshm_net_stop(struct net_device *ndev)
 124  {
 125 -       struct ivshm_net *in = netdev_priv(ndev);
 126 -
 127         ndev->operstate = IF_OPER_DOWN;
 128 -
 129 -       if (in->lstate == IVSHM_NET_STATE_RUN) {
 130 -               napi_disable(&in->napi);
 131 -               netif_stop_queue(ndev);
 132 -               ivshm_net_set_state(in, IVSHM_NET_STATE_READY);
 133 -       }
 134 +       ivshm_net_do_stop(ndev);
 135
 136         return 0;
 137  }
 138 --
 139 2.11.0
 140