From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([208.118.235.92]:56298) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1SyhnJ-0000z0-0e for qemu-devel@nongnu.org; Tue, 07 Aug 2012 07:17:54 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1SyhnH-0006Zz-Ro for qemu-devel@nongnu.org; Tue, 07 Aug 2012 07:17:48 -0400 Received: from mail-pb0-f45.google.com ([209.85.160.45]:37528) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1SyhnH-0006Zk-Lx for qemu-devel@nongnu.org; Tue, 07 Aug 2012 07:17:47 -0400 Received: by pbbro12 with SMTP id ro12so6760377pbb.4 for ; Tue, 07 Aug 2012 04:17:46 -0700 (PDT) Sender: Paolo Bonzini From: Paolo Bonzini Date: Tue, 7 Aug 2012 13:17:16 +0200 Message-Id: <1344338247-17567-2-git-send-email-pbonzini@redhat.com> In-Reply-To: <1344338247-17567-1-git-send-email-pbonzini@redhat.com> References: <1344338247-17567-1-git-send-email-pbonzini@redhat.com> Subject: [Qemu-devel] [PATCH v2 01/12] event_notifier: enable it to use pipes List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org Cc: aliguori@linux.vnet.ibm.com, stefanha@linux.vnet.ibm.com, sw@weilnetz.de This takes the eventfd emulation code from the main loop. When the EventNotifier is used for the main loop too, we need this compatibility code. Without CONFIG_EVENTFD, event_notifier_get_fd is only usable for the "read" side of the notifier, for example to set a select() handler. Reviewed-by: Anthony Liguori Signed-off-by: Paolo Bonzini --- event_notifier.c | 83 +++++++++++++++++++++++++++++++++++++++++++++----------- event_notifier.h | 3 +- 2 file modificati, 69 inserzioni(+), 17 rimozioni(-) diff --git a/event_notifier.c b/event_notifier.c index 2c207e1..88c114b 100644 --- a/event_notifier.c +++ b/event_notifier.c @@ -20,48 +20,99 @@ void event_notifier_init_fd(EventNotifier *e, int fd) { - e->fd = fd; + e->rfd = fd; + e->wfd = fd; } int event_notifier_init(EventNotifier *e, int active) { + int fds[2]; + int ret; + #ifdef CONFIG_EVENTFD - int fd = eventfd(!!active, EFD_NONBLOCK | EFD_CLOEXEC); - if (fd < 0) - return -errno; - e->fd = fd; - return 0; + ret = eventfd(0, EFD_NONBLOCK | EFD_CLOEXEC); #else - return -ENOSYS; + ret = -1; + errno = ENOSYS; #endif + if (ret >= 0) { + e->rfd = e->wfd = ret; + } else { + if (errno != ENOSYS) { + return -errno; + } + if (qemu_pipe(fds) < 0) { + return -errno; + } + ret = fcntl_setfl(fds[0], O_NONBLOCK); + if (ret < 0) { + goto fail; + } + ret = fcntl_setfl(fds[1], O_NONBLOCK); + if (ret < 0) { + goto fail; + } + e->rfd = fds[0]; + e->wfd = fds[1]; + } + if (active) { + event_notifier_set(e); + } + return 0; + +fail: + close(fds[0]); + close(fds[1]); + return ret; } void event_notifier_cleanup(EventNotifier *e) { - close(e->fd); + if (e->rfd != e->wfd) { + close(e->rfd); + } + close(e->wfd); } int event_notifier_get_fd(EventNotifier *e) { - return e->fd; + return e->rfd; } int event_notifier_set_handler(EventNotifier *e, EventNotifierHandler *handler) { - return qemu_set_fd_handler(e->fd, (IOHandler *)handler, NULL, e); + return qemu_set_fd_handler(e->rfd, (IOHandler *)handler, NULL, e); } int event_notifier_set(EventNotifier *e) { - uint64_t value = 1; - int r = write(e->fd, &value, sizeof(value)); - return r == sizeof(value); + static const uint64_t value = 1; + ssize_t ret; + + do { + ret = write(e->wfd, &value, sizeof(value)); + } while (ret < 0 && errno == EINTR); + + /* EAGAIN is fine, a read must be pending. */ + if (ret < 0 && errno != EAGAIN) { + return -1; + } + return 0; } int event_notifier_test_and_clear(EventNotifier *e) { - uint64_t value; - int r = read(e->fd, &value, sizeof(value)); - return r == sizeof(value); + int value; + ssize_t len; + char buffer[512]; + + /* Drain the notify pipe. For eventfd, only 8 bytes will be read. */ + value = 0; + do { + len = read(e->rfd, buffer, sizeof(buffer)); + value |= (len > 0); + } while ((len == -1 && errno == EINTR) || len == sizeof(buffer)); + + return value; } diff --git a/event_notifier.h b/event_notifier.h index f0ec2f2..f04d12d 100644 --- a/event_notifier.h +++ b/event_notifier.h @@ -16,7 +16,8 @@ #include "qemu-common.h" struct EventNotifier { - int fd; + int rfd; + int wfd; }; typedef void EventNotifierHandler(EventNotifier *); -- 1.7.11.2