[v3,2/3] drm/vc4: Use DMA Resv to implement VC4 wait BO IOCTL

Commit Message

Maíra Canal Dec. 20, 2024, 1:37 p.m. UTC

Since the BOs used by VC4 have DMA Reservation Objects attached to
them, waiting for seqnos to check BO availability is unnecessary.
Instead, `drm_gem_dma_resv_wait()` can be used.

Signed-off-by: Maíra Canal <[e-mail]>
---
 drivers/gpu/drm/vc4/vc4_gem.c | 25 ++++++++++++++-----------
 1 file changed, 14 insertions(+), 11 deletions(-)

Patch

diff --git a/drivers/gpu/drm/vc4/vc4_gem.c b/drivers/gpu/drm/vc4/vc4_gem.c
index 1021f45cb53c..de7be9942c13 100644
--- a/drivers/gpu/drm/vc4/vc4_gem.c
+++ b/drivers/gpu/drm/vc4/vc4_gem.c
@@ -1020,8 +1020,10 @@  vc4_wait_bo_ioctl(struct drm_device *dev, void *data,
 	struct vc4_dev *vc4 = to_vc4_dev(dev);
 	int ret;
 	struct drm_vc4_wait_bo *args = data;
-	struct drm_gem_object *gem_obj;
-	struct vc4_bo *bo;
+	unsigned long timeout_jiffies =
+		usecs_to_jiffies(div_u64(args->timeout_ns, 1000));
+	ktime_t start = ktime_get();
+	u64 delta_ns;
 
 	if (WARN_ON_ONCE(vc4->gen > VC4_GEN_4))
 		return -ENODEV;
@@ -1029,17 +1031,18 @@  vc4_wait_bo_ioctl(struct drm_device *dev, void *data,
 	if (args->pad != 0)
 		return -EINVAL;
 
-	gem_obj = drm_gem_object_lookup(file_priv, args->handle);
-	if (!gem_obj) {
-		DRM_DEBUG("Failed to look up GEM BO %d\n", args->handle);
-		return -EINVAL;
-	}
-	bo = to_vc4_bo(gem_obj);
+	ret = drm_gem_dma_resv_wait(file_priv, args->handle,
+				    true, timeout_jiffies);
 
-	ret = vc4_wait_for_seqno_ioctl_helper(dev, bo->seqno,
-					      &args->timeout_ns);
+	/* Decrement the user's timeout, in case we got interrupted
+	 * such that the ioctl will be restarted.
+	 */
+	delta_ns = ktime_to_ns(ktime_sub(ktime_get(), start));
+	if (delta_ns < args->timeout_ns)
+		args->timeout_ns -= delta_ns;
+	else
+		args->timeout_ns = 0;
 
-	drm_gem_object_put(gem_obj);
 	return ret;
 }