Merge remote-tracking branch 'stefanha/block' into staging

* stefanha/block:
  sheepdog: pass oid directly to send_pending_req()
  sheepdog: don't update inode when create_and_write fails
  block/raw-win32: Fix compiler warnings (wrong format specifiers)
  qemu-img: report size overflow error message
  cutils: change strtosz_suffix_unit function
  virtio-blk: Return UNSUPP for unknown request types
  virtio-blk: add x-data-plane=on|off performance feature
  dataplane: add virtio-blk data plane code
  virtio-blk: restore VirtIOBlkConf->config_wce flag
  iov: add qemu_iovec_concat_iov()
  test-iov: add iov_discard_front/back() testcases
  iov: add iov_discard_front/back() to remove data
  dataplane: add Linux AIO request queue
  dataplane: add event loop
  dataplane: add virtqueue vring code
  dataplane: add host memory mapping code
  configure: add CONFIG_VIRTIO_BLK_DATA_PLANE
  raw-posix: add raw_get_aio_fd() for virtio-blk-data-plane

Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>

1 files changed, 100 insertions, 0 deletions

diff --git a/hw/dataplane/event-poll.c b/hw/dataplane/event-poll.c
new file mode 100644
index 0000000000..2b55c6e255
--- /dev/null
+++ b/hw/dataplane/event-poll.c
@@ -0,0 +1,100 @@
+/*
+ * Event loop with file descriptor polling
+ *
+ * Copyright 2012 IBM, Corp.
+ * Copyright 2012 Red Hat, Inc. and/or its affiliates
+ *
+ * Authors:
+ *   Stefan Hajnoczi <stefanha@redhat.com>
+ *
+ * This work is licensed under the terms of the GNU GPL, version 2 or later.
+ * See the COPYING file in the top-level directory.
+ *
+ */
+
+#include <sys/epoll.h>
+#include "hw/dataplane/event-poll.h"
+
+/* Add an event notifier and its callback for polling */
+void event_poll_add(EventPoll *poll, EventHandler *handler,
+                    EventNotifier *notifier, EventCallback *callback)
+{
+    struct epoll_event event = {
+        .events = EPOLLIN,
+        .data.ptr = handler,
+    };
+    handler->notifier = notifier;
+    handler->callback = callback;
+    if (epoll_ctl(poll->epoll_fd, EPOLL_CTL_ADD,
+                  event_notifier_get_fd(notifier), &event) != 0) {
+        fprintf(stderr, "failed to add event handler to epoll: %m\n");
+        exit(1);
+    }
+}
+
+/* Event callback for stopping event_poll() */
+static void handle_stop(EventHandler *handler)
+{
+    /* Do nothing */
+}
+
+void event_poll_init(EventPoll *poll)
+{
+    /* Create epoll file descriptor */
+    poll->epoll_fd = epoll_create1(EPOLL_CLOEXEC);
+    if (poll->epoll_fd < 0) {
+        fprintf(stderr, "epoll_create1 failed: %m\n");
+        exit(1);
+    }
+
+    /* Set up stop notifier */
+    if (event_notifier_init(&poll->stop_notifier, 0) < 0) {
+        fprintf(stderr, "failed to init stop notifier\n");
+        exit(1);
+    }
+    event_poll_add(poll, &poll->stop_handler,
+                   &poll->stop_notifier, handle_stop);
+}
+
+void event_poll_cleanup(EventPoll *poll)
+{
+    event_notifier_cleanup(&poll->stop_notifier);
+    close(poll->epoll_fd);
+    poll->epoll_fd = -1;
+}
+
+/* Block until the next event and invoke its callback */
+void event_poll(EventPoll *poll)
+{
+    EventHandler *handler;
+    struct epoll_event event;
+    int nevents;
+
+    /* Wait for the next event.  Only do one event per call to keep the
+     * function simple, this could be changed later. */
+    do {
+        nevents = epoll_wait(poll->epoll_fd, &event, 1, -1);
+    } while (nevents < 0 && errno == EINTR);
+    if (unlikely(nevents != 1)) {
+        fprintf(stderr, "epoll_wait failed: %m\n");
+        exit(1); /* should never happen */
+    }
+
+    /* Find out which event handler has become active */
+    handler = event.data.ptr;
+
+    /* Clear the eventfd */
+    event_notifier_test_and_clear(handler->notifier);
+
+    /* Handle the event */
+    handler->callback(handler);
+}
+
+/* Stop event_poll()
+ *
+ * This function can be used from another thread.
+ */
+void event_poll_notify(EventPoll *poll)
+{
+    event_notifier_set(&poll->stop_notifier);
+}