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From: "Michael S. Tsirkin" <mst@redhat.com>
To: qemu-devel@nongnu.org
Cc: Peter Maydell <peter.maydell@linaro.org>,
	Paolo Bonzini <pbonzini@redhat.com>,
	Stefan Hajnoczi <stefanha@redhat.com>,
	Kevin Wolf <kwolf@redhat.com>,
	qemu-block@nongnu.org
Subject: [Qemu-devel] [PULL 12/15] virtio-blk: use aio handler for data plane
Date: Fri, 8 Apr 2016 11:02:45 +0300	[thread overview]
Message-ID: <1460102154-16096-13-git-send-email-mst@redhat.com> (raw)
In-Reply-To: <1460102154-16096-1-git-send-email-mst@redhat.com>

In addition to handling IO in vcpu thread and in io thread, dataplane
introduces yet another mode: handling it by AioContext.

This reuses the same handler as previous modes, which triggers races as
these were not designed to be reentrant.  Use a separate handler just
for aio, and disable regular handlers when dataplane is active.

Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
---
 include/hw/virtio/virtio-blk.h  |  2 ++
 hw/block/dataplane/virtio-blk.c | 13 +++++++++++++
 hw/block/virtio-blk.c           | 27 +++++++++++++++++----------
 3 files changed, 32 insertions(+), 10 deletions(-)

diff --git a/include/hw/virtio/virtio-blk.h b/include/hw/virtio/virtio-blk.h
index 59ae1e4..8f2b056 100644
--- a/include/hw/virtio/virtio-blk.h
+++ b/include/hw/virtio/virtio-blk.h
@@ -86,4 +86,6 @@ void virtio_blk_handle_request(VirtIOBlockReq *req, MultiReqBuffer *mrb);
 
 void virtio_blk_submit_multireq(BlockBackend *blk, MultiReqBuffer *mrb);
 
+void virtio_blk_handle_vq(VirtIOBlock *s, VirtQueue *vq);
+
 #endif
diff --git a/hw/block/dataplane/virtio-blk.c b/hw/block/dataplane/virtio-blk.c
index 2870d21..65c7f70 100644
--- a/hw/block/dataplane/virtio-blk.c
+++ b/hw/block/dataplane/virtio-blk.c
@@ -184,6 +184,17 @@ void virtio_blk_data_plane_destroy(VirtIOBlockDataPlane *s)
     g_free(s);
 }
 
+static void virtio_blk_data_plane_handle_output(VirtIODevice *vdev,
+                                                VirtQueue *vq)
+{
+    VirtIOBlock *s = (VirtIOBlock *)vdev;
+
+    assert(s->dataplane);
+    assert(s->dataplane_started);
+
+    virtio_blk_handle_vq(s, vq);
+}
+
 /* Context: QEMU global mutex held */
 void virtio_blk_data_plane_start(VirtIOBlockDataPlane *s)
 {
@@ -226,6 +237,7 @@ void virtio_blk_data_plane_start(VirtIOBlockDataPlane *s)
 
     /* Get this show started by hooking up our callbacks */
     aio_context_acquire(s->ctx);
+    virtio_set_queue_aio(s->vq, virtio_blk_data_plane_handle_output);
     virtio_queue_aio_set_host_notifier_handler(s->vq, s->ctx, true, true);
     aio_context_release(s->ctx);
     return;
@@ -262,6 +274,7 @@ void virtio_blk_data_plane_stop(VirtIOBlockDataPlane *s)
 
     /* Stop notifications for new requests from guest */
     virtio_queue_aio_set_host_notifier_handler(s->vq, s->ctx, false, false);
+    virtio_set_queue_aio(s->vq, NULL);
 
     /* Drain and switch bs back to the QEMU main loop */
     blk_set_aio_context(s->conf->conf.blk, qemu_get_aio_context());
diff --git a/hw/block/virtio-blk.c b/hw/block/virtio-blk.c
index 151fe78..3f88f8c 100644
--- a/hw/block/virtio-blk.c
+++ b/hw/block/virtio-blk.c
@@ -578,20 +578,11 @@ void virtio_blk_handle_request(VirtIOBlockReq *req, MultiReqBuffer *mrb)
     }
 }
 
-static void virtio_blk_handle_output(VirtIODevice *vdev, VirtQueue *vq)
+void virtio_blk_handle_vq(VirtIOBlock *s, VirtQueue *vq)
 {
-    VirtIOBlock *s = VIRTIO_BLK(vdev);
     VirtIOBlockReq *req;
     MultiReqBuffer mrb = {};
 
-    /* Some guests kick before setting VIRTIO_CONFIG_S_DRIVER_OK so start
-     * dataplane here instead of waiting for .set_status().
-     */
-    if (s->dataplane && !s->dataplane_started) {
-        virtio_blk_data_plane_start(s->dataplane);
-        return;
-    }
-
     blk_io_plug(s->blk);
 
     while ((req = virtio_blk_get_request(s))) {
@@ -605,6 +596,22 @@ static void virtio_blk_handle_output(VirtIODevice *vdev, VirtQueue *vq)
     blk_io_unplug(s->blk);
 }
 
+static void virtio_blk_handle_output(VirtIODevice *vdev, VirtQueue *vq)
+{
+    VirtIOBlock *s = (VirtIOBlock *)vdev;
+
+    if (s->dataplane) {
+        /* Some guests kick before setting VIRTIO_CONFIG_S_DRIVER_OK so start
+         * dataplane here instead of waiting for .set_status().
+         */
+        virtio_blk_data_plane_start(s->dataplane);
+        if (!s->dataplane_disabled) {
+            return;
+        }
+    }
+    virtio_blk_handle_vq(s, vq);
+}
+
 static void virtio_blk_dma_restart_bh(void *opaque)
 {
     VirtIOBlock *s = opaque;
-- 
MST

  parent reply	other threads:[~2016-04-08  8:03 UTC|newest]

Thread overview: 17+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-04-08  8:02 [Qemu-devel] [PULL 00/15] pci, virtio, acpi: fixes for 2.6 Michael S. Tsirkin
2016-04-08  8:02 ` [Qemu-devel] [PULL 01/15] acpi: Add missing GCC_FMT_ATTR Michael S. Tsirkin
2016-04-08  8:02 ` [Qemu-devel] [PULL 02/15] pci-testdev: fast mmio support Michael S. Tsirkin
2016-04-08  8:02 ` [Qemu-devel] [PULL 03/15] xen: piix reuse pci generic class init function Michael S. Tsirkin
2016-04-08  8:02 ` [Qemu-devel] [PULL 04/15] Sort the fw_cfg file list Michael S. Tsirkin
2016-04-08  8:02 ` [Qemu-devel] [PULL 05/15] Migration: Add i82801b11 migration data Michael S. Tsirkin
2016-04-08  8:02 ` [Qemu-devel] [PULL 06/15] virtio-balloon: reset the statistic timer to load device Michael S. Tsirkin
2016-04-08  8:02 ` [Qemu-devel] [PULL 07/15] tests/bios-tables-test: fix assert Michael S. Tsirkin
2016-04-08  8:02 ` [Qemu-devel] [PULL 08/15] virtio: make virtio_queue_notify_vq static Michael S. Tsirkin
2016-04-08  8:02 ` [Qemu-devel] [PULL 09/15] virtio-blk: fix disabled mode Michael S. Tsirkin
2016-04-08  8:02 ` [Qemu-devel] [PULL 10/15] virtio-scsi: " Michael S. Tsirkin
2016-04-08  8:02 ` [Qemu-devel] [PULL 11/15] virtio: add aio handler Michael S. Tsirkin
2016-04-08  8:02 ` Michael S. Tsirkin [this message]
2016-04-08  8:02 ` [Qemu-devel] [PULL 13/15] virtio-scsi: use aio handler for data plane Michael S. Tsirkin
2016-04-08  8:02 ` [Qemu-devel] [PULL 14/15] virtio: merge virtio_queue_aio_set_host_notifier_handler with virtio_queue_set_aio Michael S. Tsirkin
2016-04-08  8:02 ` [Qemu-devel] [PULL 15/15] hw/pci-bridge: Add missing unref in case register-bus fails Michael S. Tsirkin
2016-04-08 12:45 ` [Qemu-devel] [PULL 00/15] pci, virtio, acpi: fixes for 2.6 Peter Maydell

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