| /* |
| * 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/block.h" |
| #include "qemu/queue.h" |
| #include "qemu/sockets.h" |
| |
| struct AioHandler { |
| EventNotifier *e; |
| EventNotifierHandler *io_notify; |
| GPollFD pfd; |
| int deleted; |
| QLIST_ENTRY(AioHandler) node; |
| }; |
| |
| void aio_set_event_notifier(AioContext *ctx, |
| EventNotifier *e, |
| EventNotifierHandler *io_notify) |
| { |
| 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; |
| } |
| |
| 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 progress; |
| int count; |
| int timeout; |
| |
| 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; |
| } |
| |
| /* Run timers */ |
| progress |= timerlistgroup_run_timers(&ctx->tlg); |
| |
| /* |
| * 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); |
| |
| /* aio_notify() does not count as progress */ |
| if (node->e != &ctx->notifier) { |
| 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 */ |
| count = 0; |
| QLIST_FOREACH(node, &ctx->aio_handlers, node) { |
| if (!node->deleted && node->io_notify) { |
| events[count++] = event_notifier_get_handle(node->e); |
| } |
| } |
| |
| ctx->walking_handlers--; |
| |
| /* early return if we only have the aio_notify() fd */ |
| if (count == 1) { |
| return progress; |
| } |
| |
| /* wait until next event */ |
| while (count > 0) { |
| int ret; |
| |
| timeout = blocking ? |
| qemu_timeout_ns_to_ms(timerlistgroup_deadline_ns(&ctx->tlg)) : 0; |
| 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); |
| |
| /* aio_notify() does not count as progress */ |
| if (node->e != &ctx->notifier) { |
| 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); |
| } |
| } |
| |
| /* Try again, but only call each handler once. */ |
| events[ret - WAIT_OBJECT_0] = events[--count]; |
| } |
| |
| if (blocking) { |
| /* Run the timers a second time. We do this because otherwise aio_wait |
| * will not note progress - and will stop a drain early - if we have |
| * a timer that was not ready to run entering g_poll but is ready |
| * after g_poll. This will only do anything if a timer has expired. |
| */ |
| progress |= timerlistgroup_run_timers(&ctx->tlg); |
| } |
| |
| return progress; |
| } |