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

# gpg: Signature made Wed 04 Jan 2017 13:29:09 GMT
# 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:
  iothread: add poll-grow and poll-shrink parameters
  aio: self-tune polling time
  virtio: disable virtqueue notifications during polling
  aio: add .io_poll_begin/end() callbacks
  virtio: turn vq->notification into a nested counter
  virtio-scsi: suppress virtqueue kick during processing
  virtio-blk: suppress virtqueue kick during processing
  iothread: add polling parameters
  linux-aio: poll ring for completions
  virtio: poll virtqueues for new buffers
  aio: add polling mode to AioContext
  aio: add AioPollFn and io_poll() interface
  aio: add flag to skip fds to aio_dispatch()
  HACKING: document #include order

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

1 files changed, 21 insertions, 15 deletions

diff --git a/hw/scsi/virtio-scsi.c b/hw/scsi/virtio-scsi.c
index 34bba35d83..204e14f237 100644
--- a/hw/scsi/virtio-scsi.c
+++ b/hw/scsi/virtio-scsi.c
@@ -592,26 +592,32 @@ static void virtio_scsi_handle_cmd_req_submit(VirtIOSCSI *s, VirtIOSCSIReq *req)
 void virtio_scsi_handle_cmd_vq(VirtIOSCSI *s, VirtQueue *vq)
 {
     VirtIOSCSIReq *req, *next;
-    int ret;
+    int ret = 0;
 
     QTAILQ_HEAD(, VirtIOSCSIReq) reqs = QTAILQ_HEAD_INITIALIZER(reqs);
 
-    while ((req = virtio_scsi_pop_req(s, vq))) {
-        ret = virtio_scsi_handle_cmd_req_prepare(s, req);
-        if (!ret) {
-            QTAILQ_INSERT_TAIL(&reqs, req, next);
-        } else if (ret == -EINVAL) {
-            /* The device is broken and shouldn't process any request */
-            while (!QTAILQ_EMPTY(&reqs)) {
-                req = QTAILQ_FIRST(&reqs);
-                QTAILQ_REMOVE(&reqs, req, next);
-                blk_io_unplug(req->sreq->dev->conf.blk);
-                scsi_req_unref(req->sreq);
-                virtqueue_detach_element(req->vq, &req->elem, 0);
-                virtio_scsi_free_req(req);
+    do {
+        virtio_queue_set_notification(vq, 0);
+
+        while ((req = virtio_scsi_pop_req(s, vq))) {
+            ret = virtio_scsi_handle_cmd_req_prepare(s, req);
+            if (!ret) {
+                QTAILQ_INSERT_TAIL(&reqs, req, next);
+            } else if (ret == -EINVAL) {
+                /* The device is broken and shouldn't process any request */
+                while (!QTAILQ_EMPTY(&reqs)) {
+                    req = QTAILQ_FIRST(&reqs);
+                    QTAILQ_REMOVE(&reqs, req, next);
+                    blk_io_unplug(req->sreq->dev->conf.blk);
+                    scsi_req_unref(req->sreq);
+                    virtqueue_detach_element(req->vq, &req->elem, 0);
+                    virtio_scsi_free_req(req);
+                }
             }
         }
-    }
+
+        virtio_queue_set_notification(vq, 1);
+    } while (ret != -EINVAL && !virtio_queue_empty(vq));
 
     QTAILQ_FOREACH_SAFE(req, &reqs, next, next) {
         virtio_scsi_handle_cmd_req_submit(s, req);