target/linux/layerscape/patches-5.4/809-jailhouse-0003-ivshmem-net-fix-race-in-state-machine.patch

   1 From 0af5d7d021bb899d9c3880415267e178a20fb7a9 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] ivshmem-net: fix race in state machine
   5
   6 (cherry picked from commit 5d663baed6a89d09bae4446f6509f9957c780bc7)
   7 ---
   8  drivers/net/ivshmem-net.c | 60 ++++++++++++++++++++++++-----------------------
   9  1 file changed, 31 insertions(+), 29 deletions(-)
  10
  11 --- a/drivers/net/ivshmem-net.c
  12 +++ b/drivers/net/ivshmem-net.c
  13 @@ -36,6 +36,8 @@
  14  #define IVSHM_NET_STATE_READY  2
  15  #define IVSHM_NET_STATE_RUN    3
  16
  17 +#define IVSHM_NET_FLAG_RUN     0
  18 +
  19  #define IVSHM_NET_MTU_MIN 256
  20  #define IVSHM_NET_MTU_MAX 65535
  21  #define IVSHM_NET_MTU_DEF 16384
  22 @@ -96,6 +98,8 @@ struct ivshm_net {
  23         u32 lstate;
  24         u32 rstate;
  25
  26 +       unsigned long flags;
  27 +
  28         struct workqueue_struct *state_wq;
  29         struct work_struct state_work;
  30
  31 @@ -529,12 +533,32 @@ static void ivshm_net_run(struct net_dev
  32  {
  33         struct ivshm_net *in = netdev_priv(ndev);
  34
  35 +       if (in->lstate < IVSHM_NET_STATE_READY)
  36 +               return;
  37 +
  38 +       if (!netif_running(ndev))
  39 +               return;
  40 +
  41 +       if (test_and_set_bit(IVSHM_NET_FLAG_RUN, &in->flags))
  42 +               return;
  43 +
  44         netif_start_queue(ndev);
  45         napi_enable(&in->napi);
  46         napi_schedule(&in->napi);
  47         ivshm_net_set_state(in, IVSHM_NET_STATE_RUN);
  48  }
  49
  50 +static void ivshm_net_do_stop(struct net_device *ndev)
  51 +{
  52 +       struct ivshm_net *in = netdev_priv(ndev);
  53 +
  54 +       if (!test_and_clear_bit(IVSHM_NET_FLAG_RUN, &in->flags))
  55 +               return;
  56 +
  57 +       netif_stop_queue(ndev);
  58 +       napi_disable(&in->napi);
  59 +}
  60 +
  61  static void ivshm_net_state_change(struct work_struct *work)
  62  {
  63         struct ivshm_net *in = container_of(work, struct ivshm_net, state_work);
  64 @@ -560,21 +584,13 @@ static void ivshm_net_state_change(struc
  65                 break;
  66
  67         case IVSHM_NET_STATE_READY:
  68 +       case IVSHM_NET_STATE_RUN:
  69                 if (rstate >= IVSHM_NET_STATE_READY) {
  70                         netif_carrier_on(ndev);
  71 -                       if (ndev->flags & IFF_UP)
  72 -                               ivshm_net_run(ndev);
  73 +                       ivshm_net_run(ndev);
  74                 } else {
  75                         netif_carrier_off(ndev);
  76 -                       ivshm_net_set_state(in, IVSHM_NET_STATE_RESET);
  77 -               }
  78 -               break;
  79 -
  80 -       case IVSHM_NET_STATE_RUN:
  81 -               if (rstate < IVSHM_NET_STATE_READY) {
  82 -                       netif_stop_queue(ndev);
  83 -                       napi_disable(&in->napi);
  84 -                       netif_carrier_off(ndev);
  85 +                       ivshm_net_do_stop(ndev);
  86                         ivshm_net_set_state(in, IVSHM_NET_STATE_RESET);
  87                 }
  88                 break;
  89 @@ -584,18 +600,13 @@ static void ivshm_net_state_change(struc
  90         WRITE_ONCE(in->rstate, rstate);
  91  }
  92
  93 -static bool ivshm_net_check_state(struct net_device *ndev)
  94 +static void ivshm_net_check_state(struct net_device *ndev)
  95  {
  96         struct ivshm_net *in = netdev_priv(ndev);
  97         u32 rstate = readl(&in->ivshm_regs->rstate);
  98
  99 -       if (rstate != READ_ONCE(in->rstate) ||
 100 -           in->lstate != IVSHM_NET_STATE_RUN) {
 101 +       if (rstate != in->rstate || !test_bit(IVSHM_NET_FLAG_RUN, &in->flags))
 102                 queue_work(in->state_wq, &in->state_work);
 103 -               return false;
 104 -       }
 105 -
 106 -       return true;
 107  }
 108
 109  static irqreturn_t ivshm_net_int(int irq, void *data)
 110 @@ -617,24 +628,15 @@ static int ivshm_net_open(struct net_dev
 111
 112         netdev_reset_queue(ndev);
 113         ndev->operstate = IF_OPER_UP;
 114 -
 115 -       if (in->lstate == IVSHM_NET_STATE_READY)
 116 -               ivshm_net_run(ndev);
 117 +       ivshm_net_run(ndev);
 118
 119         return 0;
 120  }
 121
 122  static int ivshm_net_stop(struct net_device *ndev)
 123  {
 124 -       struct ivshm_net *in = netdev_priv(ndev);
 125 -
 126         ndev->operstate = IF_OPER_DOWN;
 127 -
 128 -       if (in->lstate == IVSHM_NET_STATE_RUN) {
 129 -               napi_disable(&in->napi);
 130 -               netif_stop_queue(ndev);
 131 -               ivshm_net_set_state(in, IVSHM_NET_STATE_READY);
 132 -       }
 133 +       ivshm_net_do_stop(ndev);
 134
 135         return 0;
 136  }