Re: [RFC 1/9] notifier: add validity check and notify function
From: Paolo Bonzini <pbonzini@redhat.com>
Date: 2012-07-25 06:53:29
Il 25/07/2012 00:33, Nicholas A. Bellinger ha scritto:
quoted hunk
+int event_notifier_notify(EventNotifier *e) +{ + uint64_t value = 1; + int r; + + assert(event_notifier_valid(e)); + r = write(e->fd, &value, sizeof(value)); + if (r < 0) { + return -errno; + } + assert(r == sizeof(value)); + return 0; +}
Note we now have event_notifier_set.
+#define EVENT_NOTIFIER_INITIALIZER ((EventNotifier){ .fd = -1 })This is problematic when your event notifier is inside a struct, because it is extremely easy to forget the initializer. You have to initialize them yourself. Also, the right thing to test is not whether the notifier is initialized; it is whether the notifier is actually checked in QEMU's select() loop. So, I would prefer avoiding event_notifier_valid and just use a boolean (in virtio_queue_set_host_notifier_fd_handler and virtio_queue_set_guest_notifier_fd_handler) to track whether the notifiers are in use. Paolo