Merge remote-tracking branch 'remotes/kevin/tags/for-upstream' into staging

Block patches for 2.1.0-rc2 (v2)

# gpg: Signature made Mon 14 Jul 2014 11:04:12 BST using RSA key ID C88F2FD6
# gpg: Good signature from "Kevin Wolf <kwolf@redhat.com>"

* remotes/kevin/tags/for-upstream: (22 commits)
  ide: Treat read/write beyond end as invalid
  virtio-blk: Treat read/write beyond end as invalid
  virtio-blk: Bypass error action and I/O accounting on invalid r/w
  virtio-blk: Factor common checks out of virtio_blk_handle_read/write()
  dma-helpers: Fix too long qiov
  qtest: fix vhost-user-test compilation with old GLib
  tests: Fix unterminated string output visitor enum human string
  AioContext: do not rely on aio_poll(ctx, true) result to end a loop
  virtio-blk: embed VirtQueueElement in VirtIOBlockReq
  virtio-blk: avoid g_slice_new0() for VirtIOBlockReq and VirtQueueElement
  dataplane: do not free VirtQueueElement in vring_push()
  virtio-blk: avoid dataplane VirtIOBlockReq early free
  block: Assert qiov length matches request length
  qed: Make qiov match request size until backing file EOF
  qcow2: Make qiov match request size until backing file EOF
  block: Make qiov match the request size until EOF
  AioContext: speed up aio_notify
  test-aio: fix GSource-based timer test
  block: drop aio functions that operate on the main AioContext
  block: prefer aio_poll to qemu_aio_wait
  ...

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

1 files changed, 18 insertions, 1 deletions

diff --git a/async.c b/async.c
index 5b6fe6b4cc..34af0b25ca 100644
--- a/async.c
+++ b/async.c
@@ -26,6 +26,7 @@
 #include "block/aio.h"
 #include "block/thread-pool.h"
 #include "qemu/main-loop.h"
+#include "qemu/atomic.h"
 
 /***********************************************************/
 /* bottom halves (can be seen as timers which expire ASAP) */
@@ -247,9 +248,25 @@ ThreadPool *aio_get_thread_pool(AioContext *ctx)
     return ctx->thread_pool;
 }
 
+void aio_set_dispatching(AioContext *ctx, bool dispatching)
+{
+    ctx->dispatching = dispatching;
+    if (!dispatching) {
+        /* Write ctx->dispatching before reading e.g. bh->scheduled.
+         * Optimization: this is only needed when we're entering the "unsafe"
+         * phase where other threads must call event_notifier_set.
+         */
+        smp_mb();
+    }
+}
+
 void aio_notify(AioContext *ctx)
 {
-    event_notifier_set(&ctx->notifier);
+    /* Write e.g. bh->scheduled before reading ctx->dispatching.  */
+    smp_mb();
+    if (!ctx->dispatching) {
+        event_notifier_set(&ctx->notifier);
+    }
 }
 
 static void aio_timerlist_notify(void *opaque)