[RFC PATCH v3 20/21] drm/ttm: Use drm_exec_trylock for bo initialization

["Thomas Hellström" <thomas.hellstrom@linux.intel.com>]

Buffer object initialization may be part of a drm_exec transaction.
Rather than using dma_resv_trylock, use drm_exec_trylock_obj().

RFC: This patch indicates to me that we should avoid the -ENOMEM failure
for drm_exec_trylock, Could probably use a sleeping lock here without
problems.

Cc: Christian König <christian.koenig@amd.com>
Cc: Somalapuram Amaranath <Amaranath.Somalapuram@amd.com>
Cc: Matthew Brost <matthew.brost@intel.com>
Cc: <dri-devel@lists.freedesktop.org>
Signed-off-by: Thomas Hellström <thomas.hellstrom@linux.intel.com>
---
 drivers/gpu/drm/ttm/ttm_bo.c | 21 ++++++++++++++++-----
 1 file changed, 16 insertions(+), 5 deletions(-)

diff --git a/drivers/gpu/drm/ttm/ttm_bo.c b/drivers/gpu/drm/ttm/ttm_bo.c
index 8706502edcb1..70af66b5b86e 100644
--- a/drivers/gpu/drm/ttm/ttm_bo.c
+++ b/drivers/gpu/drm/ttm/ttm_bo.c
@@ -942,10 +942,17 @@ int ttm_bo_init_reserved(struct ttm_device *bdev, struct ttm_buffer_object *bo,
 	/* passed reservation objects should already be locked,
 	 * since otherwise lockdep will be angered in radeon.
 	 */
-	if (!resv)
-		WARN_ON(!dma_resv_trylock(bo->base.resv));
-	else
+	if (!resv) {
+		if (ctx->exec) {
+			ret = drm_exec_trylock_obj(ctx->exec, &bo->base);
+			if (ret)
+				goto err_put;
+		} else {
+			WARN_ON(!dma_resv_trylock(bo->base.resv));
+		}
+	} else {
 		dma_resv_assert_held(resv);
+	}
 
 	ret = ttm_bo_validate(bo, placement, ctx);
 	if (unlikely(ret))
@@ -954,8 +961,12 @@ int ttm_bo_init_reserved(struct ttm_device *bdev, struct ttm_buffer_object *bo,
 	return 0;
 
 err_unlock:
-	if (!resv)
-		dma_resv_unlock(bo->base.resv);
+	if (!resv) {
+		if (ctx->exec)
+			drm_exec_unlock_obj(ctx->exec, &bo->base);
+		else
+			dma_resv_unlock(bo->base.resv);
+	}
 
 err_put:
 	ttm_bo_put(bo);
-- 
2.44.0