Hesham/wintun
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Revise TransitionLock usage

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The exclusive TransitionLock hold is required with all state changes
that:
- Switch adapter TUN_STATE_RUNNING -> TUN_STATE_PAUSING
- Switch media status to MediaConnectStateDisconnected
- Switch adapter to low-power state NdisDeviceStateD1-n

Because, those transitions require NBL queue to clear and stay empty.

The parts of the code that fill the NBL queue get a shared lock
before state check and release it after they are done filling the queue.

This prevents intermediate state changes while filling, and the queue
clearing parts of the code to wait for the filling parts to prevent a
race.

Starting up adapter (TUN_STATE_RESTARTING -> TUN_STATE_RUNNING,
MediaConnectStateDisconnected -> MediaConnectStateConnected, or
NdisDeviceStateDx -> NdisDeviceStateD0) does not require emptying NBL
queue and it does not need TransitionLock held.

This commit also moves TunQueueClear() out of exclusive TransitionLock
hold, because it is not necessary.

Signed-off-by: Simon Rozman <simon@rozman.si>
This commit is contained in:
Simon Rozman 2019-06-04 11:55:13 +02:00 committed by Jason A. Donenfeld
parent 486b1c374b
commit 14617f118f
1 changed files with 10 additions and 12 deletions
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14
wintun.c
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@ -775,11 +775,9 @@ static NTSTATUS TunDispatch(DEVICE_OBJECT *DeviceObject, IRP *Irp)
if (!NT_SUCCESS(status = IoAcquireRemoveLock(&ctx->Device.RemoveLock, stack->FileObject)))
goto cleanup_complete_req_and_release_remove_lock;
irql = ExAcquireSpinLockExclusive(&ctx->TransitionLock);
ASSERT(InterlockedGet64(&ctx->Device.RefCount) < MAXLONG64);
if (InterlockedIncrement64(&ctx->Device.RefCount) > 0)
TunIndicateStatus(ctx->MiniportAdapterHandle, MediaConnectStateConnected);
ExReleaseSpinLockExclusive(&ctx->TransitionLock, irql);
status = STATUS_SUCCESS;
goto cleanup_complete_req_and_release_remove_lock;
@ -788,10 +786,11 @@ static NTSTATUS TunDispatch(DEVICE_OBJECT *DeviceObject, IRP *Irp)
irql = ExAcquireSpinLockExclusive(&ctx->TransitionLock);
ASSERT(InterlockedGet64(&ctx->Device.RefCount) > 0);
if (InterlockedDecrement64(&ctx->Device.RefCount) <= 0) {
ExReleaseSpinLockExclusive(&ctx->TransitionLock, irql);
if (ctx->MiniportAdapterHandle)
TunIndicateStatus(ctx->MiniportAdapterHandle, MediaConnectStateDisconnected);
TunQueueClear(ctx, NDIS_STATUS_SEND_ABORTED);
}
} else
ExReleaseSpinLockExclusive(&ctx->TransitionLock, irql);
IoReleaseRemoveLock(&ctx->Device.RemoveLock, stack->FileObject);
@ -840,11 +839,9 @@ static NDIS_STATUS TunRestart(NDIS_HANDLE MiniportAdapterContext, PNDIS_MINIPORT
{
TUN_CTX *ctx = (TUN_CTX *)MiniportAdapterContext;
KIRQL irql = ExAcquireSpinLockExclusive(&ctx->TransitionLock);
InterlockedExchange((LONG *)&ctx->State, TUN_STATE_RESTARTING);
InterlockedExchange64(&ctx->ActiveTransactionCount, 1);
InterlockedExchange((LONG *)&ctx->State, TUN_STATE_RUNNING);
ExReleaseSpinLockExclusive(&ctx->TransitionLock, irql);
return NDIS_STATUS_SUCCESS;
}
@ -1364,11 +1361,12 @@ static NDIS_STATUS TunOidSet(_Inout_ TUN_CTX *ctx, _Inout_ NDIS_OID_REQUEST *Oid
}
OidRequest->DATA.SET_INFORMATION.BytesRead = sizeof(NDIS_DEVICE_POWER_STATE);
KIRQL irql = ExAcquireSpinLockExclusive(&ctx->TransitionLock);
NDIS_DEVICE_POWER_STATE state = *(NDIS_DEVICE_POWER_STATE *)OidRequest->DATA.SET_INFORMATION.InformationBuffer;
if (InterlockedExchange((LONG *)&ctx->PowerState, state) == NdisDeviceStateD0 && state >= NdisDeviceStateD1)
TunQueueClear(ctx, STATUS_NDIS_LOW_POWER_STATE);
KIRQL irql = ExAcquireSpinLockExclusive(&ctx->TransitionLock);
InterlockedExchange((LONG *)&ctx->PowerState, state);
ExReleaseSpinLockExclusive(&ctx->TransitionLock, irql);
if (state >= NdisDeviceStateD1)
TunQueueClear(ctx, STATUS_NDIS_LOW_POWER_STATE);
return NDIS_STATUS_SUCCESS;
}