[PATCH v2 1/3] drm/virtio: remove the global pending_notify state

[Chia-I Wu]

Call virtqueue_kick_prepare once in virtio_gpu_enable_notify, not
whenever a command is added.  This should be more efficient since
the intention is to batch commands.

Signed-off-by: Chia-I Wu <olva...@gmail.com>
---
 drivers/gpu/drm/virtio/virtgpu_drv.h |  1 -
 drivers/gpu/drm/virtio/virtgpu_vq.c  | 34 ++++++++++++++++++----------
 2 files changed, 22 insertions(+), 13 deletions(-)

diff --git a/drivers/gpu/drm/virtio/virtgpu_drv.h 
b/drivers/gpu/drm/virtio/virtgpu_drv.h
index d278c8c50f394..d3fcc25068132 100644
--- a/drivers/gpu/drm/virtio/virtgpu_drv.h
+++ b/drivers/gpu/drm/virtio/virtgpu_drv.h
@@ -178,7 +178,6 @@ struct virtio_gpu_device {
        bool vqs_ready;
 
        bool disable_notify;
-       bool pending_notify;
 
        struct ida      resource_ida;
 
diff --git a/drivers/gpu/drm/virtio/virtgpu_vq.c 
b/drivers/gpu/drm/virtio/virtgpu_vq.c
index cc02fc4bab2a5..0c9be2142ba1a 100644
--- a/drivers/gpu/drm/virtio/virtgpu_vq.c
+++ b/drivers/gpu/drm/virtio/virtgpu_vq.c
@@ -367,16 +367,13 @@ static void virtio_gpu_queue_ctrl_sgs(struct 
virtio_gpu_device *vgdev,
 
        trace_virtio_gpu_cmd_queue(vq, virtio_gpu_vbuf_ctrl_hdr(vbuf));
 
-       notify = virtqueue_kick_prepare(vq);
+       if (!vgdev->disable_notify)
+               notify = virtqueue_kick_prepare(vq);
 
        spin_unlock(&vgdev->ctrlq.qlock);
 
-       if (notify) {
-               if (vgdev->disable_notify)
-                       vgdev->pending_notify = true;
-               else
-                       virtqueue_notify(vq);
-       }
+       if (notify)
+               virtqueue_notify(vq);
 }
 
 static void virtio_gpu_queue_fenced_ctrl_buffer(struct virtio_gpu_device 
*vgdev,
@@ -432,6 +429,23 @@ static void virtio_gpu_queue_fenced_ctrl_buffer(struct 
virtio_gpu_device *vgdev,
        }
 }
 
+static void virtio_gpu_commit_ctrl(struct virtio_gpu_device *vgdev)
+{
+       struct virtqueue *vq = vgdev->ctrlq.vq;
+       bool notify;
+
+       spin_lock(&vgdev->ctrlq.qlock);
+       notify = virtqueue_kick_prepare(vq);
+       spin_unlock(&vgdev->ctrlq.qlock);
+
+       /* Do not call virtqueue_notify with the lock held because
+        * virtio_gpu_dequeue_ctrl_func may contend for the lock if an irq is
+        * generated while we are in virtqueue_notify.
+        */
+       if (notify)
+               virtqueue_notify(vq);
+}
+
 void virtio_gpu_disable_notify(struct virtio_gpu_device *vgdev)
 {
        vgdev->disable_notify = true;
@@ -440,11 +454,7 @@ void virtio_gpu_disable_notify(struct virtio_gpu_device 
*vgdev)
 void virtio_gpu_enable_notify(struct virtio_gpu_device *vgdev)
 {
        vgdev->disable_notify = false;
-
-       if (!vgdev->pending_notify)
-               return;
-       vgdev->pending_notify = false;
-       virtqueue_notify(vgdev->ctrlq.vq);
+       virtio_gpu_commit_ctrl(vgdev);
 }
 
 static void virtio_gpu_queue_ctrl_buffer(struct virtio_gpu_device *vgdev,
-- 
2.25.0.341.g760bfbb309-goog

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