diff options
Diffstat (limited to 'util/aio-win32.c')
| -rw-r--r-- | util/aio-win32.c | 421 |
1 files changed, 421 insertions, 0 deletions
diff --git a/util/aio-win32.c b/util/aio-win32.c new file mode 100644 index 0000000000..900524c9c2 --- /dev/null +++ b/util/aio-win32.c @@ -0,0 +1,421 @@ +/* + * 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/osdep.h" +#include "qemu-common.h" +#include "block/block.h" +#include "qemu/queue.h" +#include "qemu/sockets.h" +#include "qapi/error.h" +#include "qemu/rcu_queue.h" + +struct AioHandler { + EventNotifier *e; + IOHandler *io_read; + IOHandler *io_write; + EventNotifierHandler *io_notify; + GPollFD pfd; + int deleted; + void *opaque; + bool is_external; + QLIST_ENTRY(AioHandler) node; +}; + +void aio_set_fd_handler(AioContext *ctx, + int fd, + bool is_external, + IOHandler *io_read, + IOHandler *io_write, + AioPollFn *io_poll, + void *opaque) +{ + /* fd is a SOCKET in our case */ + AioHandler *node; + + qemu_lockcnt_lock(&ctx->list_lock); + QLIST_FOREACH(node, &ctx->aio_handlers, node) { + if (node->pfd.fd == fd && !node->deleted) { + break; + } + } + + /* Are we deleting the fd handler? */ + if (!io_read && !io_write) { + if (node) { + /* If aio_poll is in progress, just mark the node as deleted */ + if (qemu_lockcnt_count(&ctx->list_lock)) { + 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 list_lock. + */ + QLIST_REMOVE(node, node); + g_free(node); + } + } + } else { + HANDLE event; + + if (node == NULL) { + /* Alloc and insert if it's not already there */ + node = g_new0(AioHandler, 1); + node->pfd.fd = fd; + QLIST_INSERT_HEAD_RCU(&ctx->aio_handlers, node, node); + } + + node->pfd.events = 0; + if (node->io_read) { + node->pfd.events |= G_IO_IN; + } + if (node->io_write) { + node->pfd.events |= G_IO_OUT; + } + + node->e = &ctx->notifier; + + /* Update handler with latest information */ + node->opaque = opaque; + node->io_read = io_read; + node->io_write = io_write; + node->is_external = is_external; + + event = event_notifier_get_handle(&ctx->notifier); + WSAEventSelect(node->pfd.fd, event, + FD_READ | FD_ACCEPT | FD_CLOSE | + FD_CONNECT | FD_WRITE | FD_OOB); + } + + qemu_lockcnt_unlock(&ctx->list_lock); + aio_notify(ctx); +} + +void aio_set_fd_poll(AioContext *ctx, int fd, + IOHandler *io_poll_begin, + IOHandler *io_poll_end) +{ + /* Not implemented */ +} + +void aio_set_event_notifier(AioContext *ctx, + EventNotifier *e, + bool is_external, + EventNotifierHandler *io_notify, + AioPollFn *io_poll) +{ + AioHandler *node; + + qemu_lockcnt_lock(&ctx->list_lock); + 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); + + /* aio_poll is in progress, just mark the node as deleted */ + if (qemu_lockcnt_count(&ctx->list_lock)) { + 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 list_lock. + */ + QLIST_REMOVE(node, node); + g_free(node); + } + } + } else { + if (node == NULL) { + /* Alloc and insert if it's not already there */ + node = g_new0(AioHandler, 1); + node->e = e; + node->pfd.fd = (uintptr_t)event_notifier_get_handle(e); + node->pfd.events = G_IO_IN; + node->is_external = is_external; + QLIST_INSERT_HEAD_RCU(&ctx->aio_handlers, node, node); + + g_source_add_poll(&ctx->source, &node->pfd); + } + /* Update handler with latest information */ + node->io_notify = io_notify; + } + + qemu_lockcnt_unlock(&ctx->list_lock); + aio_notify(ctx); +} + +void aio_set_event_notifier_poll(AioContext *ctx, + EventNotifier *notifier, + EventNotifierHandler *io_poll_begin, + EventNotifierHandler *io_poll_end) +{ + /* Not implemented */ +} + +bool aio_prepare(AioContext *ctx) +{ + static struct timeval tv0; + AioHandler *node; + bool have_select_revents = false; + fd_set rfds, wfds; + + /* + * We have to walk very carefully in case aio_set_fd_handler is + * called while we're walking. + */ + qemu_lockcnt_inc(&ctx->list_lock); + + /* fill fd sets */ + FD_ZERO(&rfds); + FD_ZERO(&wfds); + QLIST_FOREACH_RCU(node, &ctx->aio_handlers, node) { + if (node->io_read) { + FD_SET ((SOCKET)node->pfd.fd, &rfds); + } + if (node->io_write) { + FD_SET ((SOCKET)node->pfd.fd, &wfds); + } + } + + if (select(0, &rfds, &wfds, NULL, &tv0) > 0) { + QLIST_FOREACH_RCU(node, &ctx->aio_handlers, node) { + node->pfd.revents = 0; + if (FD_ISSET(node->pfd.fd, &rfds)) { + node->pfd.revents |= G_IO_IN; + have_select_revents = true; + } + + if (FD_ISSET(node->pfd.fd, &wfds)) { + node->pfd.revents |= G_IO_OUT; + have_select_revents = true; + } + } + } + + qemu_lockcnt_dec(&ctx->list_lock); + return have_select_revents; +} + +bool aio_pending(AioContext *ctx) +{ + AioHandler *node; + bool result = false; + + /* + * We have to walk very carefully in case aio_set_fd_handler is + * called while we're walking. + */ + qemu_lockcnt_inc(&ctx->list_lock); + QLIST_FOREACH_RCU(node, &ctx->aio_handlers, node) { + if (node->pfd.revents && node->io_notify) { + result = true; + break; + } + + if ((node->pfd.revents & G_IO_IN) && node->io_read) { + result = true; + break; + } + if ((node->pfd.revents & G_IO_OUT) && node->io_write) { + result = true; + break; + } + } + + qemu_lockcnt_dec(&ctx->list_lock); + return result; +} + +static bool aio_dispatch_handlers(AioContext *ctx, HANDLE event) +{ + AioHandler *node; + bool progress = false; + AioHandler *tmp; + + qemu_lockcnt_inc(&ctx->list_lock); + + /* + * We have to walk very carefully in case aio_set_fd_handler is + * called while we're walking. + */ + QLIST_FOREACH_SAFE_RCU(node, &ctx->aio_handlers, node, tmp) { + int revents = node->pfd.revents; + + if (!node->deleted && + (revents || event_notifier_get_handle(node->e) == event) && + node->io_notify) { + node->pfd.revents = 0; + node->io_notify(node->e); + + /* aio_notify() does not count as progress */ + if (node->e != &ctx->notifier) { + progress = true; + } + } + + if (!node->deleted && + (node->io_read || node->io_write)) { + node->pfd.revents = 0; + if ((revents & G_IO_IN) && node->io_read) { + node->io_read(node->opaque); + progress = true; + } + if ((revents & G_IO_OUT) && node->io_write) { + node->io_write(node->opaque); + progress = true; + } + + /* if the next select() will return an event, we have progressed */ + if (event == event_notifier_get_handle(&ctx->notifier)) { + WSANETWORKEVENTS ev; + WSAEnumNetworkEvents(node->pfd.fd, event, &ev); + if (ev.lNetworkEvents) { + progress = true; + } + } + } + + if (node->deleted) { + if (qemu_lockcnt_dec_if_lock(&ctx->list_lock)) { + QLIST_REMOVE(node, node); + g_free(node); + qemu_lockcnt_inc_and_unlock(&ctx->list_lock); + } + } + } + + qemu_lockcnt_dec(&ctx->list_lock); + return progress; +} + +bool aio_dispatch(AioContext *ctx, bool dispatch_fds) +{ + bool progress; + + progress = aio_bh_poll(ctx); + if (dispatch_fds) { + progress |= aio_dispatch_handlers(ctx, INVALID_HANDLE_VALUE); + } + progress |= timerlistgroup_run_timers(&ctx->tlg); + return progress; +} + +bool aio_poll(AioContext *ctx, bool blocking) +{ + AioHandler *node; + HANDLE events[MAXIMUM_WAIT_OBJECTS + 1]; + bool progress, have_select_revents, first; + int count; + int timeout; + + aio_context_acquire(ctx); + progress = false; + + /* aio_notify can avoid the expensive event_notifier_set if + * everything (file descriptors, bottom halves, timers) will + * be re-evaluated before the next blocking poll(). This is + * already true when aio_poll is called with blocking == false; + * if blocking == true, it is only true after poll() returns, + * so disable the optimization now. + */ + if (blocking) { + atomic_add(&ctx->notify_me, 2); + } + + qemu_lockcnt_inc(&ctx->list_lock); + have_select_revents = aio_prepare(ctx); + + /* fill fd sets */ + count = 0; + QLIST_FOREACH_RCU(node, &ctx->aio_handlers, node) { + if (!node->deleted && node->io_notify + && aio_node_check(ctx, node->is_external)) { + events[count++] = event_notifier_get_handle(node->e); + } + } + + qemu_lockcnt_dec(&ctx->list_lock); + first = true; + + /* ctx->notifier is always registered. */ + assert(count > 0); + + /* Multiple iterations, all of them non-blocking except the first, + * may be necessary to process all pending events. After the first + * WaitForMultipleObjects call ctx->notify_me will be decremented. + */ + do { + HANDLE event; + int ret; + + timeout = blocking && !have_select_revents + ? qemu_timeout_ns_to_ms(aio_compute_timeout(ctx)) : 0; + if (timeout) { + aio_context_release(ctx); + } + ret = WaitForMultipleObjects(count, events, FALSE, timeout); + if (blocking) { + assert(first); + atomic_sub(&ctx->notify_me, 2); + } + if (timeout) { + aio_context_acquire(ctx); + } + + if (first) { + aio_notify_accept(ctx); + progress |= aio_bh_poll(ctx); + first = false; + } + + /* if we have any signaled events, dispatch event */ + event = NULL; + if ((DWORD) (ret - WAIT_OBJECT_0) < count) { + event = events[ret - WAIT_OBJECT_0]; + events[ret - WAIT_OBJECT_0] = events[--count]; + } else if (!have_select_revents) { + break; + } + + have_select_revents = false; + blocking = false; + + progress |= aio_dispatch_handlers(ctx, event); + } while (count > 0); + + progress |= timerlistgroup_run_timers(&ctx->tlg); + + aio_context_release(ctx); + return progress; +} + +void aio_context_setup(AioContext *ctx) +{ +} + +void aio_context_set_poll_params(AioContext *ctx, int64_t max_ns, + int64_t grow, int64_t shrink, Error **errp) +{ + error_setg(errp, "AioContext polling is not implemented on Windows"); +} |