drm/virtio: move locking into virtio_gpu_queue_ctrl_sgs

Signed-off-by: Chia-I Wu <olvaffe@gmail.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20200205181955.202485-8-olvaffe@gmail.com
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>

diff --git a/drivers/gpu/drm/virtio/virtgpu_vq.c b/drivers/gpu/drm/virtio/virtgpu_vq.c
index c8baa68..2db35f3 100644 (file)
--- a/drivers/gpu/drm/virtio/virtgpu_vq.c
+++ b/drivers/gpu/drm/virtio/virtgpu_vq.c
@@ -318,18 +318,43 @@ static struct sg_table *vmalloc_to_sgt(char *data, uint32_t size, int *sg_ents)
        return sgt;
 }
 
-static bool virtio_gpu_queue_ctrl_sgs_locked(struct virtio_gpu_device *vgdev,
-                                            struct virtio_gpu_vbuffer *vbuf,
-                                            struct scatterlist **sgs,
-                                            int outcnt,
-                                            int incnt)
+static bool virtio_gpu_queue_ctrl_sgs(struct virtio_gpu_device *vgdev,
+                                     struct virtio_gpu_vbuffer *vbuf,
+                                     struct virtio_gpu_fence *fence,
+                                     int elemcnt,
+                                     struct scatterlist **sgs,
+                                     int outcnt,
+                                     int incnt)
 {
        struct virtqueue *vq = vgdev->ctrlq.vq;
        bool notify = false;
        int ret;
 
-       if (!vgdev->vqs_ready)
+again:
+       spin_lock(&vgdev->ctrlq.qlock);
+
+       if (vq->num_free < elemcnt) {
+               spin_unlock(&vgdev->ctrlq.qlock);
+               wait_event(vgdev->ctrlq.ack_queue, vq->num_free >= elemcnt);
+               goto again;
+       }
+
+       /* now that the position of the vbuf in the virtqueue is known, we can
+        * finally set the fence id
+        */
+       if (fence) {
+               virtio_gpu_fence_emit(vgdev, virtio_gpu_vbuf_ctrl_hdr(vbuf),
+                                     fence);
+               if (vbuf->objs) {
+                       virtio_gpu_array_add_fence(vbuf->objs, &fence->f);
+                       virtio_gpu_array_unlock_resv(vbuf->objs);
+               }
+       }
+
+       if (!vgdev->vqs_ready) {
+               spin_unlock(&vgdev->ctrlq.qlock);
                return notify;
+       }
 
        ret = virtqueue_add_sgs(vq, sgs, outcnt, incnt, vbuf, GFP_ATOMIC);
        WARN_ON(ret);
@@ -338,6 +363,8 @@ static bool virtio_gpu_queue_ctrl_sgs_locked(struct virtio_gpu_device *vgdev,
 
        notify = virtqueue_kick_prepare(vq);
 
+       spin_unlock(&vgdev->ctrlq.qlock);
+
        return notify;
 }
 
@@ -345,7 +372,6 @@ static void virtio_gpu_queue_fenced_ctrl_buffer(struct virtio_gpu_device *vgdev,
                                                struct virtio_gpu_vbuffer *vbuf,
                                                struct virtio_gpu_fence *fence)
 {
-       struct virtqueue *vq = vgdev->ctrlq.vq;
        struct scatterlist *sgs[3], vcmd, vout, vresp;
        struct sg_table *sgt = NULL;
        int elemcnt = 0, outcnt = 0, incnt = 0;
@@ -387,34 +413,8 @@ static void virtio_gpu_queue_fenced_ctrl_buffer(struct virtio_gpu_device *vgdev,
                incnt++;
        }
 
-again:
-       spin_lock(&vgdev->ctrlq.qlock);
-
-       /*
-        * Make sure we have enouth space in the virtqueue.  If not
-        * wait here until we have.
-        *
-        * Without that virtio_gpu_queue_ctrl_buffer_nolock might have
-        * to wait for free space, which can result in fence ids being
-        * submitted out-of-order.
-        */
-       if (vq->num_free < elemcnt) {
-               spin_unlock(&vgdev->ctrlq.qlock);
-               wait_event(vgdev->ctrlq.ack_queue, vq->num_free >= elemcnt);
-               goto again;
-       }
-
-       if (fence) {
-               virtio_gpu_fence_emit(vgdev, virtio_gpu_vbuf_ctrl_hdr(vbuf),
-                                     fence);
-               if (vbuf->objs) {
-                       virtio_gpu_array_add_fence(vbuf->objs, &fence->f);
-                       virtio_gpu_array_unlock_resv(vbuf->objs);
-               }
-       }
-       notify = virtio_gpu_queue_ctrl_sgs_locked(vgdev, vbuf, sgs, outcnt,
-                                                 incnt);
-       spin_unlock(&vgdev->ctrlq.qlock);
+       notify = virtio_gpu_queue_ctrl_sgs(vgdev, vbuf, fence, elemcnt, sgs,
+                                          outcnt, incnt);
        if (notify) {
                if (vgdev->disable_notify)
                        vgdev->pending_notify = true;