drm/virtio: add virtio_gpu_alloc_fence()

Refactor fence creation, add fences to relevant GPU
operations and add cursor helper functions.

This removes the potential for allocation failures from the
cmd_submit and atomic_commit paths.
Now a fence will be allocated first and only after that
will we proceed with the rest of the execution.

Signed-off-by: Gustavo Padovan <gustavo.padovan@collabora.com>
Signed-off-by: Robert Foss <robert.foss@collabora.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20181112165157.32765-2-robert.foss@collabora.com
Suggested-by: Rob Herring <robh@kernel.org>
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>

5 files changed, 96 insertions, 15 deletions

diff --git a/drivers/gpu/drm/virtio/virtgpu_drv.h b/drivers/gpu/drm/virtio/virtgpu_drv.h
index 6474e83cbf3d..acd130c58e33 100644
--- a/drivers/gpu/drm/virtio/virtgpu_drv.h
+++ b/drivers/gpu/drm/virtio/virtgpu_drv.h
@@ -131,6 +131,7 @@ struct virtio_gpu_framebuffer {
         int x1, y1, x2, y2; /* dirty rect */
         spinlock_t dirty_lock;
         uint32_t hw_res_handle;
+        struct virtio_gpu_fence *fence;
 };
 #define to_virtio_gpu_framebuffer(x) \
         container_of(x, struct virtio_gpu_framebuffer, base)
@@ -349,6 +350,9 @@ void virtio_gpu_ttm_fini(struct virtio_gpu_device *vgdev);
 int virtio_gpu_mmap(struct file *filp, struct vm_area_struct *vma);
 
 /* virtio_gpu_fence.c */
+struct virtio_gpu_fence *virtio_gpu_fence_alloc(
+        struct virtio_gpu_device *vgdev);
+void virtio_gpu_fence_cleanup(struct virtio_gpu_fence *fence);
 int virtio_gpu_fence_emit(struct virtio_gpu_device *vgdev,
                           struct virtio_gpu_ctrl_hdr *cmd_hdr,
                           struct virtio_gpu_fence **fence);
diff --git a/drivers/gpu/drm/virtio/virtgpu_fence.c b/drivers/gpu/drm/virtio/virtgpu_fence.c
index 00c742a441bf..6b5d92215cfb 100644
--- a/drivers/gpu/drm/virtio/virtgpu_fence.c
+++ b/drivers/gpu/drm/virtio/virtgpu_fence.c
@@ -67,6 +67,28 @@ static const struct dma_fence_ops virtio_fence_ops = {
         .timeline_value_str  = virtio_timeline_value_str,
 };
 
+struct virtio_gpu_fence *virtio_gpu_fence_alloc(struct virtio_gpu_device *vgdev)
+{
+        struct virtio_gpu_fence_driver *drv = &vgdev->fence_drv;
+        struct virtio_gpu_fence *fence = kzalloc(sizeof(struct virtio_gpu_fence),
+                                                        GFP_ATOMIC);
+        if (!fence)
+                return fence;
+
+        fence->drv = drv;
+        dma_fence_init(&fence->f, &virtio_fence_ops, &drv->lock, drv->context, 0);
+
+        return fence;
+}
+
+void virtio_gpu_fence_cleanup(struct virtio_gpu_fence *fence)
+{
+        if (!fence)
+                return;
+
+        dma_fence_put(&fence->f);
+}
+
 int virtio_gpu_fence_emit(struct virtio_gpu_device *vgdev,
                           struct virtio_gpu_ctrl_hdr *cmd_hdr,
                           struct virtio_gpu_fence **fence)
@@ -74,15 +96,8 @@ int virtio_gpu_fence_emit(struct virtio_gpu_device *vgdev,
         struct virtio_gpu_fence_driver *drv = &vgdev->fence_drv;
         unsigned long irq_flags;
 
-        *fence = kmalloc(sizeof(struct virtio_gpu_fence), GFP_ATOMIC);
-        if ((*fence) == NULL)
-                return -ENOMEM;
-
         spin_lock_irqsave(&drv->lock, irq_flags);
-        (*fence)->drv = drv;
         (*fence)->seq = ++drv->sync_seq;
-        dma_fence_init(&(*fence)->f, &virtio_fence_ops, &drv->lock,
-                       drv->context, (*fence)->seq);
         dma_fence_get(&(*fence)->f);
         list_add_tail(&(*fence)->node, &drv->fences);
         spin_unlock_irqrestore(&drv->lock, irq_flags);
diff --git a/drivers/gpu/drm/virtio/virtgpu_ioctl.c b/drivers/gpu/drm/virtio/virtgpu_ioctl.c
index bc5afa4f906e..d69fc356df0a 100644
--- a/drivers/gpu/drm/virtio/virtgpu_ioctl.c
+++ b/drivers/gpu/drm/virtio/virtgpu_ioctl.c
@@ -168,6 +168,13 @@ static int virtio_gpu_execbuffer_ioctl(struct drm_device *dev, void *data,
                 ret = PTR_ERR(buf);
                 goto out_unresv;
         }
+
+        fence = virtio_gpu_fence_alloc(vgdev);
+        if (!fence) {
+                kfree(buf);
+                ret = -ENOMEM;
+                goto out_unresv;
+        }
         virtio_gpu_cmd_submit(vgdev, buf, exbuf->size,
                               vfpriv->ctx_id, &fence);
 
@@ -283,11 +290,17 @@ static int virtio_gpu_resource_create_ioctl(struct drm_device *dev, void *data,
                 rc_3d.nr_samples = cpu_to_le32(rc->nr_samples);
                 rc_3d.flags = cpu_to_le32(rc->flags);
 
+                fence = virtio_gpu_fence_alloc(vgdev);
+                if (!fence) {
+                        ret = -ENOMEM;
+                        goto fail_backoff;
+                }
+
                 virtio_gpu_cmd_resource_create_3d(vgdev, qobj, &rc_3d, NULL);
                 ret = virtio_gpu_object_attach(vgdev, qobj, &fence);
                 if (ret) {
-                        ttm_eu_backoff_reservation(&ticket, &validate_list);
-                        goto fail_unref;
+                        virtio_gpu_fence_cleanup(fence);
+                        goto fail_backoff;
                 }
                 ttm_eu_fence_buffer_objects(&ticket, &validate_list, &fence->f);
         }
@@ -312,6 +325,8 @@ static int virtio_gpu_resource_create_ioctl(struct drm_device *dev, void *data,
                 dma_fence_put(&fence->f);
         }
         return 0;
+fail_backoff:
+        ttm_eu_backoff_reservation(&ticket, &validate_list);
 fail_unref:
         if (vgdev->has_virgl_3d) {
                 virtio_gpu_unref_list(&validate_list);
@@ -374,6 +389,12 @@ static int virtio_gpu_transfer_from_host_ioctl(struct drm_device *dev,
                 goto out_unres;
 
         convert_to_hw_box(&box, &args->box);
+
+        fence = virtio_gpu_fence_alloc(vgdev);
+        if (!fence) {
+                ret = -ENOMEM;
+                goto out_unres;
+        }
         virtio_gpu_cmd_transfer_from_host_3d
                 (vgdev, qobj->hw_res_handle,
                  vfpriv->ctx_id, offset, args->level,
@@ -423,6 +444,11 @@ static int virtio_gpu_transfer_to_host_ioctl(struct drm_device *dev, void *data,
                         (vgdev, qobj, offset,
                          box.w, box.h, box.x, box.y, NULL);
         } else {
+                fence = virtio_gpu_fence_alloc(vgdev);
+                if (!fence) {
+                        ret = -ENOMEM;
+                        goto out_unres;
+                }
                 virtio_gpu_cmd_transfer_to_host_3d
                         (vgdev, qobj,
                          vfpriv ? vfpriv->ctx_id : 0, offset,
diff --git a/drivers/gpu/drm/virtio/virtgpu_plane.c b/drivers/gpu/drm/virtio/virtgpu_plane.c
index a9f4ae7d4483..b84ac8c25856 100644
--- a/drivers/gpu/drm/virtio/virtgpu_plane.c
+++ b/drivers/gpu/drm/virtio/virtgpu_plane.c
@@ -137,6 +137,41 @@ static void virtio_gpu_primary_plane_update(struct drm_plane *plane,
                                       plane->state->src_h >> 16);
 }
 
+static int virtio_gpu_cursor_prepare_fb(struct drm_plane *plane,
+                                        struct drm_plane_state *new_state)
+{
+        struct drm_device *dev = plane->dev;
+        struct virtio_gpu_device *vgdev = dev->dev_private;
+        struct virtio_gpu_framebuffer *vgfb;
+        struct virtio_gpu_object *bo;
+
+        if (!new_state->fb)
+                return 0;
+
+        vgfb = to_virtio_gpu_framebuffer(new_state->fb);
+        bo = gem_to_virtio_gpu_obj(vgfb->base.obj[0]);
+        if (bo && bo->dumb && (plane->state->fb != new_state->fb)) {
+                vgfb->fence = virtio_gpu_fence_alloc(vgdev);
+                if (!vgfb->fence)
+                        return -ENOMEM;
+        }
+
+        return 0;
+}
+
+static void virtio_gpu_cursor_cleanup_fb(struct drm_plane *plane,
+                                         struct drm_plane_state *old_state)
+{
+        struct virtio_gpu_framebuffer *vgfb;
+
+        if (!plane->state->fb)
+                return;
+
+        vgfb = to_virtio_gpu_framebuffer(plane->state->fb);
+        if (vgfb->fence)
+                virtio_gpu_fence_cleanup(vgfb->fence);
+}
+
 static void virtio_gpu_cursor_plane_update(struct drm_plane *plane,
                                            struct drm_plane_state *old_state)
 {
@@ -144,7 +179,6 @@ static void virtio_gpu_cursor_plane_update(struct drm_plane *plane,
         struct virtio_gpu_device *vgdev = dev->dev_private;
         struct virtio_gpu_output *output = NULL;
         struct virtio_gpu_framebuffer *vgfb;
-        struct virtio_gpu_fence *fence = NULL;
         struct virtio_gpu_object *bo = NULL;
         uint32_t handle;
         int ret = 0;
@@ -170,13 +204,13 @@ static void virtio_gpu_cursor_plane_update(struct drm_plane *plane,
                         (vgdev, bo, 0,
                          cpu_to_le32(plane->state->crtc_w),
                          cpu_to_le32(plane->state->crtc_h),
-                         0, 0, &fence);
+                         0, 0, &vgfb->fence);
                 ret = virtio_gpu_object_reserve(bo, false);
                 if (!ret) {
                         reservation_object_add_excl_fence(bo->tbo.resv,
-                                                          &fence->f);
-                        dma_fence_put(&fence->f);
-                        fence = NULL;
+                                                          &vgfb->fence->f);
+                        dma_fence_put(&vgfb->fence->f);
+                        vgfb->fence = NULL;
                         virtio_gpu_object_unreserve(bo);
                         virtio_gpu_object_wait(bo, false);
                 }
@@ -218,6 +252,8 @@ static const struct drm_plane_helper_funcs virtio_gpu_primary_helper_funcs = {
 };
 
 static const struct drm_plane_helper_funcs virtio_gpu_cursor_helper_funcs = {
+        .prepare_fb             = virtio_gpu_cursor_prepare_fb,
+        .cleanup_fb             = virtio_gpu_cursor_cleanup_fb,
         .atomic_check           = virtio_gpu_plane_atomic_check,
         .atomic_update          = virtio_gpu_cursor_plane_update,
 };
diff --git a/drivers/gpu/drm/virtio/virtgpu_vq.c b/drivers/gpu/drm/virtio/virtgpu_vq.c
index 51bef1775e47..93f2c3a51ee8 100644
--- a/drivers/gpu/drm/virtio/virtgpu_vq.c
+++ b/drivers/gpu/drm/virtio/virtgpu_vq.c
@@ -896,9 +896,9 @@ void virtio_gpu_object_detach(struct virtio_gpu_device *vgdev,
                               struct virtio_gpu_object *obj)
 {
         bool use_dma_api = !virtio_has_iommu_quirk(vgdev->vdev);
-        struct virtio_gpu_fence *fence;
 
         if (use_dma_api && obj->mapped) {
+                struct virtio_gpu_fence *fence = virtio_gpu_fence_alloc(vgdev);
                 /* detach backing and wait for the host process it ... */
                 virtio_gpu_cmd_resource_inval_backing(vgdev, obj->hw_res_handle, &fence);
                 dma_fence_wait(&fence->f, true);