drm/lima: allocate unique id per drm_file

To track if fds are pointing to the same execution context and export
the expected information to fdinfo, similar to what is done in other
drivers.
Signed-off-by: Erico Nunes <nunes.erico@gmail.com>
Signed-off-by: Qiang Yu <yuq825@gmail.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20230312233052.21095-3-nunes.erico@gmail.com

drivers/gpu/drm/lima/lima_device.h

@@ -106,6 +106,9 @@ struct lima_device {
 	struct lima_dump_head dump;
 	struct list_head error_task_list;
 	struct mutex error_task_list_lock;
+
+	struct xarray active_contexts;
+	u32 next_context_id;
 };
 
 static inline struct lima_device *

drivers/gpu/drm/lima/lima_drv.c

@@ -218,6 +218,11 @@ static int lima_drm_driver_open(struct drm_device *dev, struct drm_file *file)
 	if (!priv)
 		return -ENOMEM;
 
+	err = xa_alloc_cyclic(&ldev->active_contexts, &priv->id, priv,
+			      xa_limit_32b, &ldev->next_context_id, GFP_KERNEL);
+	if (err < 0)
+		goto err_out0;
+
 	priv->vm = lima_vm_create(ldev);
 	if (!priv->vm) {
 		err = -ENOMEM;
@@ -237,6 +242,9 @@ static int lima_drm_driver_open(struct drm_device *dev, struct drm_file *file)
 static void lima_drm_driver_postclose(struct drm_device *dev, struct drm_file *file)
 {
 	struct lima_drm_priv *priv = file->driver_priv;
+	struct lima_device *ldev = to_lima_dev(dev);
+
+	xa_erase(&ldev->active_contexts, priv->id);
 
 	lima_ctx_mgr_fini(&priv->ctx_mgr);
 	lima_vm_put(priv->vm);
@@ -388,6 +396,8 @@ static int lima_pdev_probe(struct platform_device *pdev)
 	ldev->dev = &pdev->dev;
 	ldev->id = (enum lima_gpu_id)of_device_get_match_data(&pdev->dev);
 
+	xa_init_flags(&ldev->active_contexts, XA_FLAGS_ALLOC);
+
 	platform_set_drvdata(pdev, ldev);
 
 	/* Allocate and initialize the DRM device. */
@@ -446,6 +456,8 @@ static int lima_pdev_remove(struct platform_device *pdev)
 	struct lima_device *ldev = platform_get_drvdata(pdev);
 	struct drm_device *ddev = ldev->ddev;
 
+	xa_destroy(&ldev->active_contexts);
+
 	sysfs_remove_bin_file(&ldev->dev->kobj, &lima_error_state_attr);
 
 	drm_dev_unregister(ddev);

drivers/gpu/drm/lima/lima_drv.h

@@ -20,6 +20,7 @@ struct lima_sched_task;
 struct drm_lima_gem_submit_bo;
 
 struct lima_drm_priv {
+	int id;
 	struct lima_vm *vm;
 	struct lima_ctx_mgr ctx_mgr;
 };