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Etienne PerotandgVisor bot
5f9231cd71
This CL does the following: - Add the ability for nested locks to have names. - Give names to all current uses of nested locks in the codebase. - Truncate `lockdep` debug stack traces to avoid the clutter from the `lockdep` code itself - Simplify `lockdep` to not longer require `classMap`. PiperOrigin-RevId: 491486620
42 lines
1.3 KiB
Go
42 lines
1.3 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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// Returns the two pipes in order (first locked pipe, second locked pipe).
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// The caller should unlock the second pipe first.
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//
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// Preconditions: x != y.
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// +checklocksacquire:x.mu
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// +checklocksacquire:y.mu
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func lockTwoPipes(x, y *Pipe) (*Pipe, *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.NestedLock(pipeLockPipe)
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return x, y
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}
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y.mu.Lock()
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x.mu.NestedLock(pipeLockPipe)
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return y, x
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}
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