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-rw-r--r--contrib/qemu/include/block/coroutine.h218
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diff --git a/contrib/qemu/include/block/coroutine.h b/contrib/qemu/include/block/coroutine.h
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--- a/contrib/qemu/include/block/coroutine.h
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-/*
- * QEMU coroutine implementation
- *
- * Copyright IBM, Corp. 2011
- *
- * Authors:
- * Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>
- * Kevin Wolf <kwolf@redhat.com>
- *
- * This work is licensed under the terms of the GNU LGPL, version 2 or later.
- * See the COPYING.LIB file in the top-level directory.
- *
- */
-
-#ifndef QEMU_COROUTINE_H
-#define QEMU_COROUTINE_H
-
-#include <stdbool.h>
-#include "qemu/queue.h"
-#include "qemu/timer.h"
-
-/**
- * Coroutines are a mechanism for stack switching and can be used for
- * cooperative userspace threading. These functions provide a simple but
- * useful flavor of coroutines that is suitable for writing sequential code,
- * rather than callbacks, for operations that need to give up control while
- * waiting for events to complete.
- *
- * These functions are re-entrant and may be used outside the global mutex.
- */
-
-/**
- * Mark a function that executes in coroutine context
- *
- * Functions that execute in coroutine context cannot be called directly from
- * normal functions. In the future it would be nice to enable compiler or
- * static checker support for catching such errors. This annotation might make
- * it possible and in the meantime it serves as documentation.
- *
- * For example:
- *
- * static void coroutine_fn foo(void) {
- * ....
- * }
- */
-#define coroutine_fn
-
-typedef struct Coroutine Coroutine;
-
-/**
- * Coroutine entry point
- *
- * When the coroutine is entered for the first time, opaque is passed in as an
- * argument.
- *
- * When this function returns, the coroutine is destroyed automatically and
- * execution continues in the caller who last entered the coroutine.
- */
-typedef void coroutine_fn CoroutineEntry(void *opaque);
-
-/**
- * Create a new coroutine
- *
- * Use qemu_coroutine_enter() to actually transfer control to the coroutine.
- */
-Coroutine *qemu_coroutine_create(CoroutineEntry *entry);
-
-/**
- * Transfer control to a coroutine
- *
- * The opaque argument is passed as the argument to the entry point when
- * entering the coroutine for the first time. It is subsequently ignored.
- */
-void qemu_coroutine_enter(Coroutine *coroutine, void *opaque);
-
-/**
- * Transfer control back to a coroutine's caller
- *
- * This function does not return until the coroutine is re-entered using
- * qemu_coroutine_enter().
- */
-void coroutine_fn qemu_coroutine_yield(void);
-
-/**
- * Get the currently executing coroutine
- */
-Coroutine *coroutine_fn qemu_coroutine_self(void);
-
-/**
- * Return whether or not currently inside a coroutine
- *
- * This can be used to write functions that work both when in coroutine context
- * and when not in coroutine context. Note that such functions cannot use the
- * coroutine_fn annotation since they work outside coroutine context.
- */
-bool qemu_in_coroutine(void);
-
-
-
-/**
- * CoQueues are a mechanism to queue coroutines in order to continue executing
- * them later. They provide the fundamental primitives on which coroutine locks
- * are built.
- */
-typedef struct CoQueue {
- QTAILQ_HEAD(, Coroutine) entries;
- AioContext *ctx;
-} CoQueue;
-
-/**
- * Initialise a CoQueue. This must be called before any other operation is used
- * on the CoQueue.
- */
-void qemu_co_queue_init(CoQueue *queue);
-
-/**
- * Adds the current coroutine to the CoQueue and transfers control to the
- * caller of the coroutine.
- */
-void coroutine_fn qemu_co_queue_wait(CoQueue *queue);
-
-/**
- * Adds the current coroutine to the head of the CoQueue and transfers control to the
- * caller of the coroutine.
- */
-void coroutine_fn qemu_co_queue_wait_insert_head(CoQueue *queue);
-
-/**
- * Restarts the next coroutine in the CoQueue and removes it from the queue.
- *
- * Returns true if a coroutine was restarted, false if the queue is empty.
- */
-bool qemu_co_queue_next(CoQueue *queue);
-
-/**
- * Restarts all coroutines in the CoQueue and leaves the queue empty.
- */
-void qemu_co_queue_restart_all(CoQueue *queue);
-
-/**
- * Checks if the CoQueue is empty.
- */
-bool qemu_co_queue_empty(CoQueue *queue);
-
-
-/**
- * Provides a mutex that can be used to synchronise coroutines
- */
-typedef struct CoMutex {
- bool locked;
- CoQueue queue;
-} CoMutex;
-
-/**
- * Initialises a CoMutex. This must be called before any other operation is used
- * on the CoMutex.
- */
-void qemu_co_mutex_init(CoMutex *mutex);
-
-/**
- * Locks the mutex. If the lock cannot be taken immediately, control is
- * transferred to the caller of the current coroutine.
- */
-void coroutine_fn qemu_co_mutex_lock(CoMutex *mutex);
-
-/**
- * Unlocks the mutex and schedules the next coroutine that was waiting for this
- * lock to be run.
- */
-void coroutine_fn qemu_co_mutex_unlock(CoMutex *mutex);
-
-typedef struct CoRwlock {
- bool writer;
- int reader;
- CoQueue queue;
-} CoRwlock;
-
-/**
- * Initialises a CoRwlock. This must be called before any other operation
- * is used on the CoRwlock
- */
-void qemu_co_rwlock_init(CoRwlock *lock);
-
-/**
- * Read locks the CoRwlock. If the lock cannot be taken immediately because
- * of a parallel writer, control is transferred to the caller of the current
- * coroutine.
- */
-void qemu_co_rwlock_rdlock(CoRwlock *lock);
-
-/**
- * Write Locks the mutex. If the lock cannot be taken immediately because
- * of a parallel reader, control is transferred to the caller of the current
- * coroutine.
- */
-void qemu_co_rwlock_wrlock(CoRwlock *lock);
-
-/**
- * Unlocks the read/write lock and schedules the next coroutine that was
- * waiting for this lock to be run.
- */
-void qemu_co_rwlock_unlock(CoRwlock *lock);
-
-/**
- * Yield the coroutine for a given duration
- *
- * Note this function uses timers and hence only works when a main loop is in
- * use. See main-loop.h and do not use from qemu-tool programs.
- */
-void coroutine_fn co_sleep_ns(QEMUClock *clock, int64_t ns);
-
-/**
- * Yield until a file descriptor becomes readable
- *
- * Note that this function clobbers the handlers for the file descriptor.
- */
-void coroutine_fn yield_until_fd_readable(int fd);
-#endif /* QEMU_COROUTINE_H */