[PATCH v3 1/5] drm/panfrost: Add BO labelling to Panfrost

[Adrián Larumbe]

Functions for labelling UM-exposed an internal BOs are provided. An
example of the latter would be the Perfcnt sample buffer.

This commit is done in preparation of a following one that will allow
UM to set BO labels through a new ioctl().

Signed-off-by: Adrián Larumbe <adrian.larumbe at collabora.com>
Reviewed-by: Steven Price <steven.price at arm.com>
---
 drivers/gpu/drm/panfrost/panfrost_gem.c | 42 +++++++++++++++++++++++++
 drivers/gpu/drm/panfrost/panfrost_gem.h | 17 ++++++++++
 2 files changed, 59 insertions(+)

diff --git a/drivers/gpu/drm/panfrost/panfrost_gem.c b/drivers/gpu/drm/panfrost/panfrost_gem.c
index 963f04ba2de6..4c5be7ccc9cc 100644
--- a/drivers/gpu/drm/panfrost/panfrost_gem.c
+++ b/drivers/gpu/drm/panfrost/panfrost_gem.c
@@ -1,6 +1,7 @@
 // SPDX-License-Identifier: GPL-2.0
 /* Copyright 2019 Linaro, Ltd, Rob Herring <robh at kernel.org> */
 
+#include <linux/cleanup.h>
 #include <linux/err.h>
 #include <linux/slab.h>
 #include <linux/dma-buf.h>
@@ -35,6 +36,9 @@ static void panfrost_gem_free_object(struct drm_gem_object *obj)
 	 */
 	WARN_ON_ONCE(!list_empty(&bo->mappings.list));
 
+	kfree_const(bo->label.str);
+	mutex_destroy(&bo->label.lock);
+
 	if (bo->sgts) {
 		int i;
 		int n_sgt = bo->base.base.size / SZ_2M;
@@ -260,6 +264,7 @@ struct drm_gem_object *panfrost_gem_create_object(struct drm_device *dev, size_t
 	mutex_init(&obj->mappings.lock);
 	obj->base.base.funcs = &panfrost_gem_funcs;
 	obj->base.map_wc = !pfdev->coherent;
+	mutex_init(&obj->label.lock);
 
 	return &obj->base.base;
 }
@@ -302,3 +307,40 @@ panfrost_gem_prime_import_sg_table(struct drm_device *dev,
 
 	return obj;
 }
+
+void
+panfrost_gem_set_label(struct drm_gem_object *obj, const char *label)
+{
+	struct panfrost_gem_object *bo = to_panfrost_bo(obj);
+	const char *old_label;
+
+	scoped_guard(mutex, &bo->label.lock) {
+		old_label = bo->label.str;
+		bo->label.str = label;
+	}
+
+	kfree_const(old_label);
+}
+
+void
+panfrost_gem_internal_set_label(struct drm_gem_object *obj, const char *label)
+{
+	struct panfrost_gem_object *bo = to_panfrost_bo(obj);
+	const char *str;
+
+	/* We should never attempt labelling a UM-exposed GEM object */
+	if (drm_WARN_ON(bo->base.base.dev, bo->base.base.handle_count > 0))
+		return;
+
+	if (!label)
+		return;
+
+	str = kstrdup_const(label, GFP_KERNEL);
+	if (!str) {
+		/* Failing to allocate memory for a label isn't a fatal condition */
+		drm_warn(bo->base.base.dev, "Not enough memory to allocate BO label");
+		return;
+	}
+
+	panfrost_gem_set_label(obj, str);
+}
diff --git a/drivers/gpu/drm/panfrost/panfrost_gem.h b/drivers/gpu/drm/panfrost/panfrost_gem.h
index 7516b7ecf7fe..6c187b9b66fc 100644
--- a/drivers/gpu/drm/panfrost/panfrost_gem.h
+++ b/drivers/gpu/drm/panfrost/panfrost_gem.h
@@ -41,6 +41,20 @@ struct panfrost_gem_object {
 	 */
 	size_t heap_rss_size;
 
+	/**
+	 * @label: BO tagging fields. The label can be assigned within the
+	 * driver itself or through a specific IOCTL.
+	 */
+	struct {
+		/**
+		 * @label.str: Pointer to NULL-terminated string,
+		 */
+		const char *str;
+
+		/** @lock.str: Protects access to the @label.str field. */
+		struct mutex lock;
+	} label;
+
 	bool noexec		:1;
 	bool is_heap		:1;
 };
@@ -89,4 +103,7 @@ void panfrost_gem_teardown_mappings_locked(struct panfrost_gem_object *bo);
 int panfrost_gem_shrinker_init(struct drm_device *dev);
 void panfrost_gem_shrinker_cleanup(struct drm_device *dev);
 
+void panfrost_gem_set_label(struct drm_gem_object *obj, const char *label);
+void panfrost_gem_internal_set_label(struct drm_gem_object *obj, const char *label);
+
 #endif /* __PANFROST_GEM_H__ */

base-commit: 9ff4fdf4f44b69237c0afc1d3a8dac916ce66f3e
-- 
2.48.1