drm/imagination: vm: make use of GPUVM's drm_exec helper

Make use of GPUVM's drm_exec helper functions preventing direct access
to GPUVM internal data structures, such as the external object list.

This is especially important to ensure following the locking rules
around the GPUVM external object list.

Fixes: ff5f643d ("drm/imagination: Add GEM and VM related code")
Reviewed-by: Donald Robson <donald.robson@imgtec.com>
Signed-off-by: Danilo Krummrich <dakr@redhat.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20231129220835.297885-3-dakr@redhat.com

drivers/gpu/drm/imagination/pvr_vm.c

@@ -327,48 +327,6 @@ pvr_vm_bind_op_unmap_init(struct pvr_vm_bind_op *bind_op,
 	return err;
 }
 
-static int
-pvr_vm_bind_op_lock_resvs(struct drm_exec *exec, struct pvr_vm_bind_op *bind_op)
-{
-	drm_exec_until_all_locked(exec) {
-		struct drm_gem_object *r_obj = &bind_op->vm_ctx->dummy_gem;
-		struct drm_gpuvm *gpuvm = &bind_op->vm_ctx->gpuvm_mgr;
-		struct pvr_gem_object *pvr_obj = bind_op->pvr_obj;
-		struct drm_gpuvm_bo *gpuvm_bo;
-
-		/* Acquire lock on the vm_context's reserve object. */
-		int err = drm_exec_lock_obj(exec, r_obj);
-
-		drm_exec_retry_on_contention(exec);
-		if (err)
-			return err;
-
-		/* Acquire lock on all BOs in the context. */
-		list_for_each_entry(gpuvm_bo, &gpuvm->extobj.list,
-				    list.entry.extobj) {
-			err = drm_exec_lock_obj(exec, gpuvm_bo->obj);
-
-			drm_exec_retry_on_contention(exec);
-			if (err)
-				return err;
-		}
-
-		/* Unmap operations don't have an object to lock. */
-		if (!pvr_obj)
-			break;
-
-		/* Acquire lock on the GEM being mapped. */
-		err = drm_exec_lock_obj(exec,
-					gem_from_pvr_gem(bind_op->pvr_obj));
-
-		drm_exec_retry_on_contention(exec);
-		if (err)
-			return err;
-	}
-
-	return 0;
-}
-
 /**
  * pvr_vm_gpuva_map() - Insert a mapping into a memory context.
  * @op: gpuva op containing the remap details.
@@ -725,6 +683,20 @@ void pvr_destroy_vm_contexts_for_file(struct pvr_file *pvr_file)
 	}
 }
 
+static int
+pvr_vm_lock_extra(struct drm_gpuvm_exec *vm_exec)
+{
+	struct pvr_vm_bind_op *bind_op = vm_exec->extra.priv;
+	struct pvr_gem_object *pvr_obj = bind_op->pvr_obj;
+
+	/* Unmap operations don't have an object to lock. */
+	if (!pvr_obj)
+		return 0;
+
+	/* Acquire lock on the GEM being mapped. */
+	return drm_exec_lock_obj(&vm_exec->exec, gem_from_pvr_gem(pvr_obj));
+}
+
 /**
  * pvr_vm_map() - Map a section of physical memory into a section of
  * device-virtual memory.
@@ -752,7 +724,15 @@ pvr_vm_map(struct pvr_vm_context *vm_ctx, struct pvr_gem_object *pvr_obj,
 	   u64 pvr_obj_offset, u64 device_addr, u64 size)
 {
 	struct pvr_vm_bind_op bind_op = {0};
-	struct drm_exec exec;
+	struct drm_gpuvm_exec vm_exec = {
+		.vm = &vm_ctx->gpuvm_mgr,
+		.flags = DRM_EXEC_INTERRUPTIBLE_WAIT |
+			 DRM_EXEC_IGNORE_DUPLICATES,
+		.extra = {
+			.fn = pvr_vm_lock_extra,
+			.priv = &bind_op,
+		},
+	};
 
 	int err = pvr_vm_bind_op_map_init(&bind_op, vm_ctx, pvr_obj,
 					  pvr_obj_offset, device_addr,
@@ -761,18 +741,15 @@ pvr_vm_map(struct pvr_vm_context *vm_ctx, struct pvr_gem_object *pvr_obj,
 	if (err)
 		return err;
 
-	drm_exec_init(&exec,
-		      DRM_EXEC_INTERRUPTIBLE_WAIT | DRM_EXEC_IGNORE_DUPLICATES);
-
 	pvr_gem_object_get(pvr_obj);
 
-	err = pvr_vm_bind_op_lock_resvs(&exec, &bind_op);
+	err = drm_gpuvm_exec_lock(&vm_exec);
 	if (err)
 		goto err_cleanup;
 
 	err = pvr_vm_bind_op_exec(&bind_op);
 
-	drm_exec_fini(&exec);
+	drm_gpuvm_exec_unlock(&vm_exec);
 
 err_cleanup:
 	pvr_vm_bind_op_fini(&bind_op);
@@ -798,24 +775,28 @@ int
 pvr_vm_unmap(struct pvr_vm_context *vm_ctx, u64 device_addr, u64 size)
 {
 	struct pvr_vm_bind_op bind_op = {0};
-	struct drm_exec exec;
+	struct drm_gpuvm_exec vm_exec = {
+		.vm = &vm_ctx->gpuvm_mgr,
+		.flags = DRM_EXEC_INTERRUPTIBLE_WAIT |
+			 DRM_EXEC_IGNORE_DUPLICATES,
+		.extra = {
+			.fn = pvr_vm_lock_extra,
+			.priv = &bind_op,
+		},
+	};
 
 	int err = pvr_vm_bind_op_unmap_init(&bind_op, vm_ctx, device_addr,
 					    size);
-
 	if (err)
 		return err;
 
-	drm_exec_init(&exec,
-		      DRM_EXEC_INTERRUPTIBLE_WAIT | DRM_EXEC_IGNORE_DUPLICATES);
-
-	err = pvr_vm_bind_op_lock_resvs(&exec, &bind_op);
+	err = drm_gpuvm_exec_lock(&vm_exec);
 	if (err)
 		goto err_cleanup;
 
 	err = pvr_vm_bind_op_exec(&bind_op);
 
-	drm_exec_fini(&exec);
+	drm_gpuvm_exec_unlock(&vm_exec);
 
 err_cleanup:
 	pvr_vm_bind_op_fini(&bind_op);