Merge remote-tracking branch 'remotes/stefanha/tags/block-pull-request' into staging

Block pull request

# gpg: Signature made Fri 29 Aug 2014 17:25:58 BST using RSA key ID 81AB73C8
# gpg: Good signature from "Stefan Hajnoczi <stefanha@redhat.com>"
# gpg:                 aka "Stefan Hajnoczi <stefanha@gmail.com>"

* remotes/stefanha/tags/block-pull-request: (35 commits)
  quorum: Fix leak of opts in quorum_open
  blkverify: Fix leak of opts in blkverify_open
  nfs: Fix leak of opts in nfs_file_open
  curl: Don't deref NULL pointer in call to aio_poll.
  curl: Allow a cookie or cookies to be sent with http/https requests.
  virtio-blk: allow drive_del with dataplane
  block: acquire AioContext in do_drive_del()
  linux-aio: avoid deadlock in nested aio_poll() calls
  qemu-iotests: add multiwrite test cases
  block: fix overlapping multiwrite requests
  nbd: Follow the BDS' AIO context
  block: Add AIO context notifiers
  nbd: Drop nbd_can_read()
  sheepdog: fix a core dump while do auto-reconnecting
  aio-win32: add support for sockets
  qemu-coroutine-io: fix for Win32
  AioContext: introduce aio_prepare
  aio-win32: add aio_set_dispatching optimization
  test-aio: test timers on Windows too
  AioContext: export and use aio_dispatch
  ...

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

1 files changed, 19 insertions, 39 deletions

diff --git a/aio-posix.c b/aio-posix.c
index 2eada2e049..d3ac06e238 100644
--- a/aio-posix.c
+++ b/aio-posix.c
@@ -100,6 +100,11 @@ void aio_set_event_notifier(AioContext *ctx,
                        (IOHandler *)io_read, NULL, notifier);
 }
 
+bool aio_prepare(AioContext *ctx)
+{
+    return false;
+}
+
 bool aio_pending(AioContext *ctx)
 {
     AioHandler *node;
@@ -119,12 +124,21 @@ bool aio_pending(AioContext *ctx)
     return false;
 }
 
-static bool aio_dispatch(AioContext *ctx)
+bool aio_dispatch(AioContext *ctx)
 {
     AioHandler *node;
     bool progress = false;
 
     /*
+     * If there are callbacks left that have been queued, we need to call them.
+     * 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 aio_poll loops).
+     */
+    if (aio_bh_poll(ctx)) {
+        progress = true;
+    }
+
+    /*
      * We have to walk very carefully in case aio_set_fd_handler is
      * called while we're walking.
      */
@@ -184,22 +198,9 @@ bool aio_poll(AioContext *ctx, bool blocking)
 
     /* 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 happens
-     * in two cases:
-     *
-     * 1) when aio_poll is called with blocking == false
-     *
-     * 2) when we are called after poll().  If we are called before
-     *    poll(), bottom halves will not be re-evaluated and we need
-     *    aio_notify() if blocking == true.
-     *
-     * The first aio_dispatch() only does something when AioContext is
-     * running as a GSource, and in that case aio_poll is used only
-     * with blocking == false, so this optimization is already quite
-     * effective.  However, the code is ugly and should be restructured
-     * to have a single aio_dispatch() call.  To do this, we need to
-     * reorganize aio_poll into a prepare/poll/dispatch model like
-     * glib's.
+     * 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.
      *
      * If we're in a nested event loop, ctx->dispatching might be true.
      * In that case we can restore it just before returning, but we
@@ -207,26 +208,6 @@ bool aio_poll(AioContext *ctx, bool blocking)
      */
     aio_set_dispatching(ctx, !blocking);
 
-    /*
-     * If there are callbacks left that have been queued, we need to call them.
-     * 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 aio_poll loops).
-     */
-    if (aio_bh_poll(ctx)) {
-        blocking = false;
-        progress = true;
-    }
-
-    /* Re-evaluate condition (1) above.  */
-    aio_set_dispatching(ctx, !blocking);
-    if (aio_dispatch(ctx)) {
-        progress = true;
-    }
-
-    if (progress && !blocking) {
-        goto out;
-    }
-
     ctx->walking_handlers++;
 
     g_array_set_size(ctx->pollfds, 0);
@@ -249,7 +230,7 @@ bool aio_poll(AioContext *ctx, bool blocking)
     /* wait until next event */
     ret = qemu_poll_ns((GPollFD *)ctx->pollfds->data,
                          ctx->pollfds->len,
-                         blocking ? timerlistgroup_deadline_ns(&ctx->tlg) : 0);
+                         blocking ? aio_compute_timeout(ctx) : 0);
 
     /* if we have any readable fds, dispatch event */
     if (ret > 0) {
@@ -268,7 +249,6 @@ bool aio_poll(AioContext *ctx, bool blocking)
         progress = true;
     }
 
-out:
     aio_set_dispatching(ctx, was_dispatching);
     return progress;
 }