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Diffstat (limited to 'contrib/qemu/include/block/aio.h')
| -rw-r--r-- | contrib/qemu/include/block/aio.h | 247 |
1 files changed, 0 insertions, 247 deletions
diff --git a/contrib/qemu/include/block/aio.h b/contrib/qemu/include/block/aio.h deleted file mode 100644 index 183679374fa..00000000000 --- a/contrib/qemu/include/block/aio.h +++ /dev/null @@ -1,247 +0,0 @@ -/* - * QEMU aio implementation - * - * Copyright IBM, Corp. 2008 - * - * Authors: - * Anthony Liguori <aliguori@us.ibm.com> - * - * This work is licensed under the terms of the GNU GPL, version 2. See - * the COPYING file in the top-level directory. - * - */ - -#ifndef QEMU_AIO_H -#define QEMU_AIO_H - -#include "qemu-common.h" -#include "qemu/queue.h" -#include "qemu/event_notifier.h" - -typedef struct BlockDriverAIOCB BlockDriverAIOCB; -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); - -typedef 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; - - /* 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; -} AioContext; - -/* Returns 1 if there are still outstanding AIO requests; 0 otherwise */ -typedef int (AioFlushEventNotifierHandler)(EventNotifier *e); - -/** - * 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. - */ -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. - * - * Bottom halves that are scheduled from a bottom half handler are instantly - * invoked. This can create an infinite loop if a bottom half handler - * schedules itself. - * - * @bh: The bottom half to be scheduled. - */ -void qemu_bh_schedule(QEMUBH *bh); - -/** - * qemu_bh_cancel: Cancel execution of a bottom half. - * - * Canceling execution of a bottom half undoes the effect of calls to - * qemu_bh_schedule without freeing its resources yet. While cancellation - * itself is also wait-free and thread-safe, it can of course race with the - * loop that executes bottom halves unless you are holding the iothread - * mutex. This makes it mostly useless if you are not holding the mutex. - * - * @bh: The bottom half to be canceled. - */ -void qemu_bh_cancel(QEMUBH *bh); - -/** - *qemu_bh_delete: Cancel execution of a bottom half and free its resources. - * - * Deleting a bottom half frees the memory that was allocated for it by - * qemu_bh_new. It also implies canceling the bottom half if it was - * scheduled. - * - * @bh: The bottom half to be deleted. - */ -void qemu_bh_delete(QEMUBH *bh); - -/* Return whether there are any pending callbacks from the GSource - * attached to the AioContext. - * - * This is used internally in the implementation of the GSource. - */ -bool aio_pending(AioContext *ctx); - -/* Progress in completing AIO work to occur. This can issue new pending - * aio as a result of executing I/O completion or bh callbacks. - * - * If there is no pending AIO operation or completion (bottom half), - * return false. If there are pending AIO operations of bottom halves, - * return true. - * - * If there are no pending bottom halves, but there are pending AIO - * operations, it may not be possible to make any progress without - * blocking. If @blocking is true, this function will wait until one - * or more AIO events have completed, to ensure something has moved - * before returning. - */ -bool aio_poll(AioContext *ctx, bool blocking); - -#ifdef CONFIG_POSIX -/* Returns 1 if there are still outstanding AIO requests; 0 otherwise */ -typedef int (AioFlushHandler)(void *opaque); - -/* Register a file descriptor and associated callbacks. Behaves very similarly - * to qemu_set_fd_handler2. Unlike qemu_set_fd_handler2, these callbacks will - * be invoked when using qemu_aio_wait(). - * - * Code that invokes AIO completion functions should rely on this function - * instead of qemu_set_fd_handler[2]. - */ -void aio_set_fd_handler(AioContext *ctx, - int fd, - IOHandler *io_read, - IOHandler *io_write, - AioFlushHandler *io_flush, - void *opaque); -#endif - -/* Register an event notifier and associated callbacks. Behaves very similarly - * to event_notifier_set_handler. Unlike event_notifier_set_handler, these callbacks - * will be invoked when using qemu_aio_wait(). - * - * Code that invokes AIO completion functions should rely on this function - * instead of event_notifier_set_handler. - */ -void aio_set_event_notifier(AioContext *ctx, - EventNotifier *notifier, - EventNotifierHandler *io_read, - AioFlushEventNotifierHandler *io_flush); - -/* Return a GSource that lets the main loop poll the file descriptors attached - * to this AioContext. - */ -GSource *aio_get_g_source(AioContext *ctx); - -/* Return the ThreadPool bound to this AioContext */ -struct ThreadPool *aio_get_thread_pool(AioContext *ctx); - -/* Functions to operate on the main QEMU AioContext. */ - -bool qemu_aio_wait(void); -void qemu_aio_set_event_notifier(EventNotifier *notifier, - EventNotifierHandler *io_read, - AioFlushEventNotifierHandler *io_flush); - -#ifdef CONFIG_POSIX -void qemu_aio_set_fd_handler(int fd, - IOHandler *io_read, - IOHandler *io_write, - AioFlushHandler *io_flush, - void *opaque); -#endif - -#endif |