diff options
Diffstat (limited to 'aio-win32.c')
| -rw-r--r-- | aio-win32.c | 215 |
1 files changed, 215 insertions, 0 deletions
diff --git a/aio-win32.c b/aio-win32.c new file mode 100644 index 0000000000..a84eb71246 --- /dev/null +++ b/aio-win32.c @@ -0,0 +1,215 @@ +/* + * QEMU aio implementation + * + * Copyright IBM Corp., 2008 + * Copyright Red Hat Inc., 2012 + * + * Authors: + * Anthony Liguori <aliguori@us.ibm.com> + * Paolo Bonzini <pbonzini@redhat.com> + * + * This work is licensed under the terms of the GNU GPL, version 2. See + * the COPYING file in the top-level directory. + * + * Contributions after 2012-01-13 are licensed under the terms of the + * GNU GPL, version 2 or (at your option) any later version. + */ + +#include "qemu-common.h" +#include "block.h" +#include "qemu-queue.h" +#include "qemu_socket.h" + +struct AioHandler { + EventNotifier *e; + EventNotifierHandler *io_notify; + AioFlushEventNotifierHandler *io_flush; + GPollFD pfd; + int deleted; + QLIST_ENTRY(AioHandler) node; +}; + +void aio_set_event_notifier(AioContext *ctx, + EventNotifier *e, + EventNotifierHandler *io_notify, + AioFlushEventNotifierHandler *io_flush) +{ + AioHandler *node; + + QLIST_FOREACH(node, &ctx->aio_handlers, node) { + if (node->e == e && !node->deleted) { + break; + } + } + + /* Are we deleting the fd handler? */ + if (!io_notify) { + if (node) { + g_source_remove_poll(&ctx->source, &node->pfd); + + /* If the lock is held, just mark the node as deleted */ + if (ctx->walking_handlers) { + node->deleted = 1; + node->pfd.revents = 0; + } else { + /* Otherwise, delete it for real. We can't just mark it as + * deleted because deleted nodes are only cleaned up after + * releasing the walking_handlers lock. + */ + QLIST_REMOVE(node, node); + g_free(node); + } + } + } else { + if (node == NULL) { + /* Alloc and insert if it's not already there */ + node = g_malloc0(sizeof(AioHandler)); + node->e = e; + node->pfd.fd = (uintptr_t)event_notifier_get_handle(e); + node->pfd.events = G_IO_IN; + QLIST_INSERT_HEAD(&ctx->aio_handlers, node, node); + + g_source_add_poll(&ctx->source, &node->pfd); + } + /* Update handler with latest information */ + node->io_notify = io_notify; + node->io_flush = io_flush; + } + + aio_notify(ctx); +} + +bool aio_pending(AioContext *ctx) +{ + AioHandler *node; + + QLIST_FOREACH(node, &ctx->aio_handlers, node) { + if (node->pfd.revents && node->io_notify) { + return true; + } + } + + return false; +} + +bool aio_poll(AioContext *ctx, bool blocking) +{ + AioHandler *node; + HANDLE events[MAXIMUM_WAIT_OBJECTS + 1]; + bool busy, progress; + int count; + + progress = false; + + /* + * If there are callbacks left that have been queued, we need to call then. + * Do not call select in this case, because it is possible that the caller + * does not need a complete flush (as is the case for qemu_aio_wait loops). + */ + if (aio_bh_poll(ctx)) { + blocking = false; + progress = true; + } + + /* + * Then dispatch any pending callbacks from the GSource. + * + * We have to walk very carefully in case qemu_aio_set_fd_handler is + * called while we're walking. + */ + node = QLIST_FIRST(&ctx->aio_handlers); + while (node) { + AioHandler *tmp; + + ctx->walking_handlers++; + + if (node->pfd.revents && node->io_notify) { + node->pfd.revents = 0; + node->io_notify(node->e); + progress = true; + } + + tmp = node; + node = QLIST_NEXT(node, node); + + ctx->walking_handlers--; + + if (!ctx->walking_handlers && tmp->deleted) { + QLIST_REMOVE(tmp, node); + g_free(tmp); + } + } + + if (progress && !blocking) { + return true; + } + + ctx->walking_handlers++; + + /* fill fd sets */ + busy = false; + count = 0; + QLIST_FOREACH(node, &ctx->aio_handlers, node) { + /* If there aren't pending AIO operations, don't invoke callbacks. + * Otherwise, if there are no AIO requests, qemu_aio_wait() would + * wait indefinitely. + */ + if (!node->deleted && node->io_flush) { + if (node->io_flush(node->e) == 0) { + continue; + } + busy = true; + } + if (!node->deleted && node->io_notify) { + events[count++] = event_notifier_get_handle(node->e); + } + } + + ctx->walking_handlers--; + + /* No AIO operations? Get us out of here */ + if (!busy) { + return progress; + } + + /* wait until next event */ + for (;;) { + int timeout = blocking ? INFINITE : 0; + int ret = WaitForMultipleObjects(count, events, FALSE, timeout); + + /* if we have any signaled events, dispatch event */ + if ((DWORD) (ret - WAIT_OBJECT_0) >= count) { + break; + } + + blocking = false; + + /* we have to walk very carefully in case + * qemu_aio_set_fd_handler is called while we're walking */ + node = QLIST_FIRST(&ctx->aio_handlers); + while (node) { + AioHandler *tmp; + + ctx->walking_handlers++; + + if (!node->deleted && + event_notifier_get_handle(node->e) == events[ret - WAIT_OBJECT_0] && + node->io_notify) { + node->io_notify(node->e); + progress = true; + } + + tmp = node; + node = QLIST_NEXT(node, node); + + ctx->walking_handlers--; + + if (!ctx->walking_handlers && tmp->deleted) { + QLIST_REMOVE(tmp, node); + g_free(tmp); + } + } + } + + return progress; +} |