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alistair23-linux
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ivshmem-net: fix race in state machine 

(cherry picked from commit 5d663baed6a89d09bae4446f6509f9957c780bc7)
5.4-rM2-2.2.x-imx-squashed
Mans Rullgard 2016-11-24 18:46:41 +00:00 committed by Dong Aisheng
parent 874fde9266
commit db011fdece
1 changed files with 31 additions and 29 deletions
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60
drivers/net/ivshmem-net.c
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@ -36,6 +36,8 @@
#define IVSHM_NET_STATE_READY 2
#define IVSHM_NET_STATE_RUN 3
#define IVSHM_NET_FLAG_RUN 0
#define IVSHM_NET_MTU_MIN 256
#define IVSHM_NET_MTU_MAX 65535
#define IVSHM_NET_MTU_DEF 16384
@ -96,6 +98,8 @@ struct ivshm_net {
u32 lstate;
u32 rstate;
unsigned long flags;
struct workqueue_struct *state_wq;
struct work_struct state_work;
@ -529,12 +533,32 @@ static void ivshm_net_run(struct net_device *ndev)
{
struct ivshm_net *in = netdev_priv(ndev);
if (in->lstate < IVSHM_NET_STATE_READY)
return;
if (!netif_running(ndev))
return;
if (test_and_set_bit(IVSHM_NET_FLAG_RUN, &in->flags))
return;
netif_start_queue(ndev);
napi_enable(&in->napi);
napi_schedule(&in->napi);
ivshm_net_set_state(in, IVSHM_NET_STATE_RUN);
}
static void ivshm_net_do_stop(struct net_device *ndev)
{
struct ivshm_net *in = netdev_priv(ndev);
if (!test_and_clear_bit(IVSHM_NET_FLAG_RUN, &in->flags))
return;
netif_stop_queue(ndev);
napi_disable(&in->napi);
}
static void ivshm_net_state_change(struct work_struct *work)
{
struct ivshm_net *in = container_of(work, struct ivshm_net, state_work);
@ -560,21 +584,13 @@ static void ivshm_net_state_change(struct work_struct *work)
break;
case IVSHM_NET_STATE_READY:
case IVSHM_NET_STATE_RUN:
if (rstate >= IVSHM_NET_STATE_READY) {
netif_carrier_on(ndev);
if (ndev->flags & IFF_UP)
ivshm_net_run(ndev);
ivshm_net_run(ndev);
} else {
netif_carrier_off(ndev);
ivshm_net_set_state(in, IVSHM_NET_STATE_RESET);
}
break;
case IVSHM_NET_STATE_RUN:
if (rstate < IVSHM_NET_STATE_READY) {
netif_stop_queue(ndev);
napi_disable(&in->napi);
netif_carrier_off(ndev);
ivshm_net_do_stop(ndev);
ivshm_net_set_state(in, IVSHM_NET_STATE_RESET);
}
break;
@ -584,18 +600,13 @@ static void ivshm_net_state_change(struct work_struct *work)
WRITE_ONCE(in->rstate, rstate);
}
static bool ivshm_net_check_state(struct net_device *ndev)
static void ivshm_net_check_state(struct net_device *ndev)
{
struct ivshm_net *in = netdev_priv(ndev);
u32 rstate = readl(&in->ivshm_regs->rstate);
if (rstate != READ_ONCE(in->rstate) ||
in->lstate != IVSHM_NET_STATE_RUN) {
if (rstate != in->rstate || !test_bit(IVSHM_NET_FLAG_RUN, &in->flags))
queue_work(in->state_wq, &in->state_work);
return false;
}
return true;
}
static irqreturn_t ivshm_net_int(int irq, void *data)
@ -617,24 +628,15 @@ static int ivshm_net_open(struct net_device *ndev)
netdev_reset_queue(ndev);
ndev->operstate = IF_OPER_UP;
if (in->lstate == IVSHM_NET_STATE_READY)
ivshm_net_run(ndev);
ivshm_net_run(ndev);
return 0;
}
static int ivshm_net_stop(struct net_device *ndev)
{
struct ivshm_net *in = netdev_priv(ndev);
ndev->operstate = IF_OPER_DOWN;
if (in->lstate == IVSHM_NET_STATE_RUN) {
napi_disable(&in->napi);
netif_stop_queue(ndev);
ivshm_net_set_state(in, IVSHM_NET_STATE_READY);
}
ivshm_net_do_stop(ndev);
return 0;
}