drm/vc4: Use DRM Execution Contexts

VC4 has internal copies of `drm_gem_lock_reservations()` and
`drm_gem_unlock_reservations()` within the driver. Ideally, these
hard-coded functions should be replaced with the generic functions
provided by DRM common code. However, instead of using the DRM GEM
functions to (un)lock reservations, transition to the new DRM Execution
Contexts API.

Signed-off-by: Maíra Canal <mcanal@igalia.com>
Acked-by: Christian König <christian.koenig@amd.com>
Reviewed-by: Melissa Wen <mwen@igalia.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20241220134204.634577-2-mcanal@igalia.com

2 files changed, 22 insertions, 78 deletions

diff --git a/drivers/gpu/drm/vc4/Kconfig b/drivers/gpu/drm/vc4/Kconfig
index 6cc7b7e6294a..123ab0ce1781 100644
--- a/drivers/gpu/drm/vc4/Kconfig
+++ b/drivers/gpu/drm/vc4/Kconfig
@@ -14,6 +14,7 @@ config DRM_VC4
 	select DRM_DISPLAY_HDMI_HELPER
 	select DRM_DISPLAY_HDMI_STATE_HELPER
 	select DRM_DISPLAY_HELPER
+	select DRM_EXEC
 	select DRM_KMS_HELPER
 	select DRM_GEM_DMA_HELPER
 	select DRM_PANEL_BRIDGE
diff --git a/drivers/gpu/drm/vc4/vc4_gem.c b/drivers/gpu/drm/vc4/vc4_gem.c
index 22bccd69eb62..1021f45cb53c 100644
--- a/drivers/gpu/drm/vc4/vc4_gem.c
+++ b/drivers/gpu/drm/vc4/vc4_gem.c
@@ -29,6 +29,7 @@
 #include <linux/sched/signal.h>
 #include <linux/dma-fence-array.h>
 
+#include <drm/drm_exec.h>
 #include <drm/drm_syncobj.h>
 
 #include "uapi/drm/vc4_drm.h"
@@ -578,19 +579,6 @@ vc4_update_bo_seqnos(struct vc4_exec_info *exec, uint64_t seqno)
 	}
 }
 
-static void
-vc4_unlock_bo_reservations(struct drm_device *dev,
-			   struct vc4_exec_info *exec,
-			   struct ww_acquire_ctx *acquire_ctx)
-{
-	int i;
-
-	for (i = 0; i < exec->bo_count; i++)
-		dma_resv_unlock(exec->bo[i]->resv);
-
-	ww_acquire_fini(acquire_ctx);
-}
-
 /* Takes the reservation lock on all the BOs being referenced, so that
  * at queue submit time we can update the reservations.
  *
@@ -599,70 +587,23 @@ vc4_unlock_bo_reservations(struct drm_device *dev,
  * to vc4, so we don't attach dma-buf fences to them.
  */
 static int
-vc4_lock_bo_reservations(struct drm_device *dev,
-			 struct vc4_exec_info *exec,
-			 struct ww_acquire_ctx *acquire_ctx)
+vc4_lock_bo_reservations(struct vc4_exec_info *exec,
+			 struct drm_exec *exec_ctx)
 {
-	int contended_lock = -1;
-	int i, ret;
-	struct drm_gem_object *bo;
-
-	ww_acquire_init(acquire_ctx, &reservation_ww_class);
-
-retry:
-	if (contended_lock != -1) {
-		bo = exec->bo[contended_lock];
-		ret = dma_resv_lock_slow_interruptible(bo->resv, acquire_ctx);
-		if (ret) {
-			ww_acquire_done(acquire_ctx);
-			return ret;
-		}
-	}
-
-	for (i = 0; i < exec->bo_count; i++) {
-		if (i == contended_lock)
-			continue;
-
-		bo = exec->bo[i];
-
-		ret = dma_resv_lock_interruptible(bo->resv, acquire_ctx);
-		if (ret) {
-			int j;
-
-			for (j = 0; j < i; j++) {
-				bo = exec->bo[j];
-				dma_resv_unlock(bo->resv);
-			}
-
-			if (contended_lock != -1 && contended_lock >= i) {
-				bo = exec->bo[contended_lock];
-
-				dma_resv_unlock(bo->resv);
-			}
-
-			if (ret == -EDEADLK) {
-				contended_lock = i;
-				goto retry;
-			}
-
-			ww_acquire_done(acquire_ctx);
-			return ret;
-		}
-	}
-
-	ww_acquire_done(acquire_ctx);
+	int ret;
 
 	/* Reserve space for our shared (read-only) fence references,
 	 * before we commit the CL to the hardware.
 	 */
-	for (i = 0; i < exec->bo_count; i++) {
-		bo = exec->bo[i];
+	drm_exec_init(exec_ctx, DRM_EXEC_INTERRUPTIBLE_WAIT, exec->bo_count);
+	drm_exec_until_all_locked(exec_ctx) {
+		ret = drm_exec_prepare_array(exec_ctx, exec->bo,
+					     exec->bo_count, 1);
+	}
 
-		ret = dma_resv_reserve_fences(bo->resv, 1);
-		if (ret) {
-			vc4_unlock_bo_reservations(dev, exec, acquire_ctx);
-			return ret;
-		}
+	if (ret) {
+		drm_exec_fini(exec_ctx);
+		return ret;
 	}
 
 	return 0;
@@ -679,7 +620,7 @@ retry:
  */
 static int
 vc4_queue_submit(struct drm_device *dev, struct vc4_exec_info *exec,
-		 struct ww_acquire_ctx *acquire_ctx,
+		 struct drm_exec *exec_ctx,
 		 struct drm_syncobj *out_sync)
 {
 	struct vc4_dev *vc4 = to_vc4_dev(dev);
@@ -708,7 +649,7 @@ vc4_queue_submit(struct drm_device *dev, struct vc4_exec_info *exec,
 
 	vc4_update_bo_seqnos(exec, seqno);
 
-	vc4_unlock_bo_reservations(dev, exec, acquire_ctx);
+	drm_exec_fini(exec_ctx);
 
 	list_add_tail(&exec->head, &vc4->bin_job_list);
 
@@ -1123,7 +1064,7 @@ vc4_submit_cl_ioctl(struct drm_device *dev, void *data,
 	struct drm_vc4_submit_cl *args = data;
 	struct drm_syncobj *out_sync = NULL;
 	struct vc4_exec_info *exec;
-	struct ww_acquire_ctx acquire_ctx;
+	struct drm_exec exec_ctx;
 	struct dma_fence *in_fence;
 	int ret = 0;
 
@@ -1216,7 +1157,7 @@ vc4_submit_cl_ioctl(struct drm_device *dev, void *data,
 	if (ret)
 		goto fail;
 
-	ret = vc4_lock_bo_reservations(dev, exec, &acquire_ctx);
+	ret = vc4_lock_bo_reservations(exec, &exec_ctx);
 	if (ret)
 		goto fail;
 
@@ -1224,7 +1165,7 @@ vc4_submit_cl_ioctl(struct drm_device *dev, void *data,
 		out_sync = drm_syncobj_find(file_priv, args->out_sync);
 		if (!out_sync) {
 			ret = -EINVAL;
-			goto fail;
+			goto fail_unreserve;
 		}
 
 		/* We replace the fence in out_sync in vc4_queue_submit since
@@ -1239,7 +1180,7 @@ vc4_submit_cl_ioctl(struct drm_device *dev, void *data,
 	 */
 	exec->args = NULL;
 
-	ret = vc4_queue_submit(dev, exec, &acquire_ctx, out_sync);
+	ret = vc4_queue_submit(dev, exec, &exec_ctx, out_sync);
 
 	/* The syncobj isn't part of the exec data and we need to free our
 	 * reference even if job submission failed.
@@ -1248,13 +1189,15 @@ vc4_submit_cl_ioctl(struct drm_device *dev, void *data,
 		drm_syncobj_put(out_sync);
 
 	if (ret)
-		goto fail;
+		goto fail_unreserve;
 
 	/* Return the seqno for our job. */
 	args->seqno = vc4->emit_seqno;
 
 	return 0;
 
+fail_unreserve:
+	drm_exec_fini(&exec_ctx);
 fail:
 	vc4_complete_exec(&vc4->base, exec);