36 lines
1.0 KiB
Go
36 lines
1.0 KiB
Go
// Copyright 2019 The gVisor Authors.
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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package pipe
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import (
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"unsafe"
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)
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// lockTwoPipes locks both x.mu and y.mu in an order that is guaranteed to be
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// consistent for both lockTwoPipes(x, y) and lockTwoPipes(y, x), such that
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// concurrent calls cannot deadlock.
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//
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// Preconditions: x != y.
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func lockTwoPipes(x, y *Pipe) {
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// Lock the two pipes in order of increasing address.
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if uintptr(unsafe.Pointer(x)) < uintptr(unsafe.Pointer(y)) {
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x.mu.Lock()
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y.mu.Lock()
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} else {
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y.mu.Lock()
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x.mu.Lock()
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}
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}
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