dma-buf: add enum dma_resv_usage v4

This change adds the dma_resv_usage enum and allows us to specify why a
dma_resv object is queried for its containing fences.

Additional to that a dma_resv_usage_rw() helper function is added to aid
retrieving the fences for a read or write userspace submission.

This is then deployed to the different query functions of the dma_resv
object and all of their users. When the write paratermer was previously
true we now use DMA_RESV_USAGE_WRITE and DMA_RESV_USAGE_READ otherwise.

v2: add KERNEL/OTHER in separate patch
v3: some kerneldoc suggestions by Daniel
v4: some more kerneldoc suggestions by Daniel, fix missing cases lost in
    the rebase pointed out by Bas.

Signed-off-by: Christian König <christian.koenig@amd.com>
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: https://patchwork.freedesktop.org/patch/msgid/20220407085946.744568-2-christian.koenig@amd.com

1 files changed, 3 insertions, 1 deletions

diff --git a/drivers/gpu/drm/vgem/vgem_fence.c b/drivers/gpu/drm/vgem/vgem_fence.c
index 2ddbebca87d9..91fc4940c65a 100644
--- a/drivers/gpu/drm/vgem/vgem_fence.c
+++ b/drivers/gpu/drm/vgem/vgem_fence.c
@@ -130,6 +130,7 @@ int vgem_fence_attach_ioctl(struct drm_device *dev,
 	struct vgem_file *vfile = file->driver_priv;
 	struct dma_resv *resv;
 	struct drm_gem_object *obj;
+	enum dma_resv_usage usage;
 	struct dma_fence *fence;
 	int ret;
 
@@ -151,7 +152,8 @@ int vgem_fence_attach_ioctl(struct drm_device *dev,
 
 	/* Check for a conflicting fence */
 	resv = obj->resv;
-	if (!dma_resv_test_signaled(resv, arg->flags & VGEM_FENCE_WRITE)) {
+	usage = dma_resv_usage_rw(arg->flags & VGEM_FENCE_WRITE);
+	if (!dma_resv_test_signaled(resv, usage)) {
 		ret = -EBUSY;
 		goto err_fence;
 	}