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src/sparse-0.4.4/perl/t/include/block/aio.h  view on Meta::CPAN

typedef void BlockDriverCompletionFunc(void *opaque, int ret);

typedef struct AIOCBInfo {
    void (*cancel)(BlockDriverAIOCB *acb);
    size_t aiocb_size;
} AIOCBInfo;

struct BlockDriverAIOCB {
    const AIOCBInfo *aiocb_info;
    BlockDriverState *bs;
    BlockDriverCompletionFunc *cb;
    void *opaque;
};

void *qemu_aio_get(const AIOCBInfo *aiocb_info, BlockDriverState *bs,
                   BlockDriverCompletionFunc *cb, void *opaque);
void qemu_aio_release(void *p);

typedef struct AioHandler AioHandler;
typedef void QEMUBHFunc(void *opaque);
typedef void IOHandler(void *opaque);

struct AioContext {
    GSource source;

    /* The list of registered AIO handlers */
    QLIST_HEAD(, AioHandler) aio_handlers;

    /* This is a simple lock used to protect the aio_handlers list.
     * Specifically, it's used to ensure that no callbacks are removed while
     * we're walking and dispatching callbacks.
     */
    int walking_handlers;

    /* lock to protect between bh's adders and deleter */
    QemuMutex bh_lock;
    /* Anchor of the list of Bottom Halves belonging to the context */
    struct QEMUBH *first_bh;

    /* A simple lock used to protect the first_bh list, and ensure that
     * no callbacks are removed while we're walking and dispatching callbacks.
     */
    int walking_bh;

    /* Used for aio_notify.  */
    EventNotifier notifier;

    /* GPollFDs for aio_poll() */
    GArray *pollfds;

    /* Thread pool for performing work and receiving completion callbacks */
    struct ThreadPool *thread_pool;

    /* TimerLists for calling timers - one per clock type */
    QEMUTimerListGroup tlg;
};

/**
 * aio_context_new: Allocate a new AioContext.
 *
 * AioContext provide a mini event-loop that can be waited on synchronously.
 * They also provide bottom halves, a service to execute a piece of code
 * as soon as possible.
 */
AioContext *aio_context_new(void);

/**
 * aio_context_ref:
 * @ctx: The AioContext to operate on.
 *
 * Add a reference to an AioContext.
 */
void aio_context_ref(AioContext *ctx);

/**
 * aio_context_unref:
 * @ctx: The AioContext to operate on.
 *
 * Drop a reference to an AioContext.
 */
void aio_context_unref(AioContext *ctx);

/**
 * aio_bh_new: Allocate a new bottom half structure.
 *
 * Bottom halves are lightweight callbacks whose invocation is guaranteed
 * to be wait-free, thread-safe and signal-safe.  The #QEMUBH structure
 * is opaque and must be allocated prior to its use.
 */
QEMUBH *aio_bh_new(AioContext *ctx, QEMUBHFunc *cb, void *opaque);

/**
 * aio_notify: Force processing of pending events.
 *
 * Similar to signaling a condition variable, aio_notify forces
 * aio_wait to exit, so that the next call will re-examine pending events.
 * The caller of aio_notify will usually call aio_wait again very soon,
 * or go through another iteration of the GLib main loop.  Hence, aio_notify
 * also has the side effect of recalculating the sets of file descriptors
 * that the main loop waits for.
 *
 * Calling aio_notify is rarely necessary, because for example scheduling
 * a bottom half calls it already.
 */
void aio_notify(AioContext *ctx);

/**
 * aio_bh_poll: Poll bottom halves for an AioContext.
 *
 * These are internal functions used by the QEMU main loop.
 * And notice that multiple occurrences of aio_bh_poll cannot
 * be called concurrently
 */
int aio_bh_poll(AioContext *ctx);

/**
 * qemu_bh_schedule: Schedule a bottom half.
 *
 * Scheduling a bottom half interrupts the main loop and causes the
 * execution of the callback that was passed to qemu_bh_new.
 *