86d1e36f29
This should work on all byte addressable host systems using GCC/clang to build. The QEMU slirp code has been pried out of QEMU and stubs have been created to solve where the current slirp is entangled with the QEMU code. Ths slirp/simh directory contains all the necessary include and glue files to make this useful. Everything in the slirp directory is unmodified QEMU code.
54 lines
1.6 KiB
C
54 lines
1.6 KiB
C
/*
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* Recursive FIFO lock
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*
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* Copyright Red Hat, Inc. 2013
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*
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* Authors:
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* Stefan Hajnoczi <stefanha@redhat.com>
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*
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* This work is licensed under the terms of the GNU GPL, version 2 or later.
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* See the COPYING file in the top-level directory.
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*
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*/
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#ifndef QEMU_RFIFOLOCK_H
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#define QEMU_RFIFOLOCK_H
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#include "qemu/thread.h"
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/* Recursive FIFO lock
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*
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* This lock provides more features than a plain mutex:
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*
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* 1. Fairness - enforces FIFO order.
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* 2. Nesting - can be taken recursively.
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* 3. Contention callback - optional, called when thread must wait.
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*
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* The recursive FIFO lock is heavyweight so prefer other synchronization
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* primitives if you do not need its features.
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*/
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typedef struct {
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QemuMutex lock; /* protects all fields */
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/* FIFO order */
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unsigned int head; /* active ticket number */
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unsigned int tail; /* waiting ticket number */
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QemuCond cond; /* used to wait for our ticket number */
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/* Nesting */
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QemuThread owner_thread; /* thread that currently has ownership */
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unsigned int nesting; /* amount of nesting levels */
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/* Contention callback */
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void (*cb)(void *); /* called when thread must wait, with ->lock
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* held so it may not recursively lock/unlock
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*/
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void *cb_opaque;
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} RFifoLock;
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void rfifolock_init(RFifoLock *r, void (*cb)(void *), void *opaque);
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void rfifolock_destroy(RFifoLock *r);
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void rfifolock_lock(RFifoLock *r);
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void rfifolock_unlock(RFifoLock *r);
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#endif /* QEMU_RFIFOLOCK_H */
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