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

# gpg: Signature made Mon 20 Jun 2016 15:05:24 BST
# gpg:                using RSA key 0x9CA4ABB381AB73C8
# gpg: Good signature from "Stefan Hajnoczi <stefanha@redhat.com>"
# gpg:                 aka "Stefan Hajnoczi <stefanha@gmail.com>"
# Primary key fingerprint: 8695 A8BF D3F9 7CDA AC35  775A 9CA4 ABB3 81AB 73C8

* remotes/stefanha/tags/block-pull-request:
  backup: follow AioContext change gracefully
  mirror: follow AioContext change gracefully
  blockjob: add AioContext attached callback
  block: use safe iteration over AioContext notifiers
  blockjob: add block_job_get_aio_context()
  blockjob: add pause points
  blockjob: rename block_job_is_paused()
  blockjob: move iostatus reset out of block_job_enter()
  block: process before_write_notifiers in bdrv_co_discard
  block: fix race in bdrv_co_discard with drive-mirror
  block: fixed BdrvTrackedRequest filling in bdrv_co_discard
  libqos: add qvirtqueue_cleanup()
  libqos: drop duplicated virtio_pci.h definitions
  libqos: drop duplicated virtio_scsi.h definitions
  libqos: drop duplicated virtio_blk.h definitions
  libqos: drop duplicated virtio_vring.h structs
  libqos: drop duplicated virtio_ring.h bit definitions
  libqos: drop duplicated virtio_config.h definitions
  libqos: drop duplicated PCI vendor ID definition
  libqos: use virtio_ids.h for device ID definitions

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

2 files changed, 41 insertions, 12 deletions

diff --git a/include/block/block_int.h b/include/block/block_int.h
index 688c6be009..205715600b 100644
--- a/include/block/block_int.h
+++ b/include/block/block_int.h
@@ -361,6 +361,7 @@ typedef struct BdrvAioNotifier {
     void (*detach_aio_context)(void *opaque);
 
     void *opaque;
+    bool deleted;
 
     QLIST_ENTRY(BdrvAioNotifier) list;
 } BdrvAioNotifier;
@@ -427,6 +428,7 @@ struct BlockDriverState {
      * BDS may register themselves in this list to be notified of changes
      * regarding this BDS's context */
     QLIST_HEAD(, BdrvAioNotifier) aio_notifiers;
+    bool walking_aio_notifiers; /* to make removal during iteration safe */
 
     char filename[PATH_MAX];
     char backing_file[PATH_MAX]; /* if non zero, the image is a diff of
diff --git a/include/block/blockjob.h b/include/block/blockjob.h
index 00ac4184cc..7dc720c82b 100644
--- a/include/block/blockjob.h
+++ b/include/block/blockjob.h
@@ -70,6 +70,27 @@ typedef struct BlockJobDriver {
      * never both.
      */
     void (*abort)(BlockJob *job);
+
+    /**
+     * If the callback is not NULL, it will be invoked when the job transitions
+     * into the paused state.  Paused jobs must not perform any asynchronous
+     * I/O or event loop activity.  This callback is used to quiesce jobs.
+     */
+    void coroutine_fn (*pause)(BlockJob *job);
+
+    /**
+     * If the callback is not NULL, it will be invoked when the job transitions
+     * out of the paused state.  Any asynchronous I/O or event loop activity
+     * should be restarted from this callback.
+     */
+    void coroutine_fn (*resume)(BlockJob *job);
+
+    /*
+     * If the callback is not NULL, it will be invoked before the job is
+     * resumed in a new AioContext.  This is the place to move any resources
+     * besides job->blk to the new AioContext.
+     */
+    void (*attached_aio_context)(BlockJob *job, AioContext *new_context);
 } BlockJobDriver;
 
 /**
@@ -119,13 +140,19 @@ struct BlockJob {
     bool user_paused;
 
     /**
-     * Set to false by the job while it is in a quiescent state, where
-     * no I/O is pending and the job has yielded on any condition
-     * that is not detected by #aio_poll, such as a timer.
+     * Set to false by the job while the coroutine has yielded and may be
+     * re-entered by block_job_enter().  There may still be I/O or event loop
+     * activity pending.
      */
     bool busy;
 
     /**
+     * Set to true by the job while it is in a quiescent state, where
+     * no I/O or event loop activity is pending.
+     */
+    bool paused;
+
+    /**
      * Set to true when the job is ready to be completed.
      */
     bool ready;
@@ -299,6 +326,15 @@ bool block_job_is_cancelled(BlockJob *job);
 BlockJobInfo *block_job_query(BlockJob *job);
 
 /**
+ * block_job_pause_point:
+ * @job: The job that is ready to pause.
+ *
+ * Pause now if block_job_pause() has been called.  Block jobs that perform
+ * lots of I/O must call this between requests so that the job can be paused.
+ */
+void coroutine_fn block_job_pause_point(BlockJob *job);
+
+/**
  * block_job_pause:
  * @job: The job to be paused.
  *
@@ -348,15 +384,6 @@ void block_job_event_completed(BlockJob *job, const char *msg);
 void block_job_event_ready(BlockJob *job);
 
 /**
- * block_job_is_paused:
- * @job: The job being queried.
- *
- * Returns whether the job is currently paused, or will pause
- * as soon as it reaches a sleeping point.
- */
-bool block_job_is_paused(BlockJob *job);
-
-/**
  * block_job_cancel_sync:
  * @job: The job to be canceled.
  *