1 files changed, 275 insertions, 0 deletions
diff --git a/drivers/gpu/drm/drm_managed.c b/drivers/gpu/drm/drm_managed.c
new file mode 100644
index 000000000000..9cebfe370a65
--- /dev/null
+++ b/drivers/gpu/drm/drm_managed.c
@@ -0,0 +1,275 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2020 Intel
+ *
+ * Based on drivers/base/devres.c
+ */
+
+#include <drm/drm_managed.h>
+
+#include <linux/list.h>
+#include <linux/slab.h>
+#include <linux/spinlock.h>
+
+#include <drm/drm_device.h>
+#include <drm/drm_print.h>
+
+/**
+ * DOC: managed resources
+ *
+ * Inspired by struct &device managed resources, but tied to the lifetime of
+ * struct &drm_device, which can outlive the underlying physical device, usually
+ * when userspace has some open files and other handles to resources still open.
+ *
+ * Release actions can be added with drmm_add_action(), memory allocations can
+ * be done directly with drmm_kmalloc() and the related functions. Everything
+ * will be released on the final drm_dev_put() in reverse order of how the
+ * release actions have been added and memory has been allocated since driver
+ * loading started with drm_dev_init().
+ *
+ * Note that release actions and managed memory can also be added and removed
+ * during the lifetime of the driver, all the functions are fully concurrent
+ * safe. But it is recommended to use managed resources only for resources that
+ * change rarely, if ever, during the lifetime of the &drm_device instance.
+ */
+
+struct drmres_node {
+	struct list_head	entry;
+	drmres_release_t	release;
+	const char		*name;
+	size_t			size;
+};
+
+struct drmres {
+	struct drmres_node		node;
+	/*
+	 * Some archs want to perform DMA into kmalloc caches
+	 * and need a guaranteed alignment larger than
+	 * the alignment of a 64-bit integer.
+	 * Thus we use ARCH_KMALLOC_MINALIGN here and get exactly the same
+	 * buffer alignment as if it was allocated by plain kmalloc().
+	 */
+	u8 __aligned(ARCH_KMALLOC_MINALIGN) data[];
+};
+
+static void free_dr(struct drmres *dr)
+{
+	kfree_const(dr->node.name);
+	kfree(dr);
+}
+
+void drm_managed_release(struct drm_device *dev)
+{
+	struct drmres *dr, *tmp;
+
+	drm_dbg_drmres(dev, "drmres release begin\n");
+	list_for_each_entry_safe(dr, tmp, &dev->managed.resources, node.entry) {
+		drm_dbg_drmres(dev, "REL %p %s (%zu bytes)\n",
+			       dr, dr->node.name, dr->node.size);
+
+		if (dr->node.release)
+			dr->node.release(dev, dr->node.size ? *(void **)&dr->data : NULL);
+
+		list_del(&dr->node.entry);
+		free_dr(dr);
+	}
+	drm_dbg_drmres(dev, "drmres release end\n");
+}
+
+/*
+ * Always inline so that kmalloc_track_caller tracks the actual interesting
+ * caller outside of drm_managed.c.
+ */
+static __always_inline struct drmres * alloc_dr(drmres_release_t release,
+						size_t size, gfp_t gfp, int nid)
+{
+	size_t tot_size;
+	struct drmres *dr;
+
+	/* We must catch any near-SIZE_MAX cases that could overflow. */
+	if (unlikely(check_add_overflow(sizeof(*dr), size, &tot_size)))
+		return NULL;
+
+	dr = kmalloc_node_track_caller(tot_size, gfp, nid);
+	if (unlikely(!dr))
+		return NULL;
+
+	memset(dr, 0, offsetof(struct drmres, data));
+
+	INIT_LIST_HEAD(&dr->node.entry);
+	dr->node.release = release;
+	dr->node.size = size;
+
+	return dr;
+}
+
+static void del_dr(struct drm_device *dev, struct drmres *dr)
+{
+	list_del_init(&dr->node.entry);
+
+	drm_dbg_drmres(dev, "DEL %p %s (%lu bytes)\n",
+		       dr, dr->node.name, (unsigned long) dr->node.size);
+}
+
+static void add_dr(struct drm_device *dev, struct drmres *dr)
+{
+	unsigned long flags;
+
+	spin_lock_irqsave(&dev->managed.lock, flags);
+	list_add(&dr->node.entry, &dev->managed.resources);
+	spin_unlock_irqrestore(&dev->managed.lock, flags);
+
+	drm_dbg_drmres(dev, "ADD %p %s (%lu bytes)\n",
+		       dr, dr->node.name, (unsigned long) dr->node.size);
+}
+
+/**
+ * drmm_add_final_kfree - add release action for the final kfree()
+ * @dev: DRM device
+ * @container: pointer to the kmalloc allocation containing @dev
+ *
+ * Since the allocation containing the struct &drm_device must be allocated
+ * before it can be initialized with drm_dev_init() there's no way to allocate
+ * that memory with drmm_kmalloc(). To side-step this chicken-egg problem the
+ * pointer for this final kfree() must be specified by calling this function. It
+ * will be released in the final drm_dev_put() for @dev, after all other release
+ * actions installed through drmm_add_action() have been processed.
+ */
+void drmm_add_final_kfree(struct drm_device *dev, void *container)
+{
+	WARN_ON(dev->managed.final_kfree);
+	WARN_ON(dev < (struct drm_device *) container);
+	WARN_ON(dev + 1 > (struct drm_device *) (container + ksize(container)));
+	dev->managed.final_kfree = container;
+}
+EXPORT_SYMBOL(drmm_add_final_kfree);
+
+int __drmm_add_action(struct drm_device *dev,
+		      drmres_release_t action,
+		      void *data, const char *name)
+{
+	struct drmres *dr;
+	void **void_ptr;
+
+	dr = alloc_dr(action, data ? sizeof(void*) : 0,
+		      GFP_KERNEL | __GFP_ZERO,
+		      dev_to_node(dev->dev));
+	if (!dr) {
+		drm_dbg_drmres(dev, "failed to add action %s for %p\n",
+			       name, data);
+		return -ENOMEM;
+	}
+
+	dr->node.name = kstrdup_const(name, GFP_KERNEL);
+	if (data) {
+		void_ptr = (void **)&dr->data;
+		*void_ptr = data;
+	}
+
+	add_dr(dev, dr);
+
+	return 0;
+}
+EXPORT_SYMBOL(__drmm_add_action);
+
+int __drmm_add_action_or_reset(struct drm_device *dev,
+			       drmres_release_t action,
+			       void *data, const char *name)
+{
+	int ret;
+
+	ret = __drmm_add_action(dev, action, data, name);
+	if (ret)
+		action(dev, data);
+
+	return ret;
+}
+EXPORT_SYMBOL(__drmm_add_action_or_reset);
+
+/**
+ * drmm_kmalloc - &drm_device managed kmalloc()
+ * @dev: DRM device
+ * @size: size of the memory allocation
+ * @gfp: GFP allocation flags
+ *
+ * This is a &drm_device managed version of kmalloc(). The allocated memory is
+ * automatically freed on the final drm_dev_put(). Memory can also be freed
+ * before the final drm_dev_put() by calling drmm_kfree().
+ */
+void *drmm_kmalloc(struct drm_device *dev, size_t size, gfp_t gfp)
+{
+	struct drmres *dr;
+
+	dr = alloc_dr(NULL, size, gfp, dev_to_node(dev->dev));
+	if (!dr) {
+		drm_dbg_drmres(dev, "failed to allocate %zu bytes, %u flags\n",
+			       size, gfp);
+		return NULL;
+	}
+	dr->node.name = kstrdup_const("kmalloc", GFP_KERNEL);
+
+	add_dr(dev, dr);
+
+	return dr->data;
+}
+EXPORT_SYMBOL(drmm_kmalloc);
+
+/**
+ * drmm_kstrdup - &drm_device managed kstrdup()
+ * @dev: DRM device
+ * @s: 0-terminated string to be duplicated
+ * @gfp: GFP allocation flags
+ *
+ * This is a &drm_device managed version of kstrdup(). The allocated memory is
+ * automatically freed on the final drm_dev_put() and works exactly like a
+ * memory allocation obtained by drmm_kmalloc().
+ */
+char *drmm_kstrdup(struct drm_device *dev, const char *s, gfp_t gfp)
+{
+	size_t size;
+	char *buf;
+
+	if (!s)
+		return NULL;
+
+	size = strlen(s) + 1;
+	buf = drmm_kmalloc(dev, size, gfp);
+	if (buf)
+		memcpy(buf, s, size);
+	return buf;
+}
+EXPORT_SYMBOL_GPL(drmm_kstrdup);
+
+/**
+ * drmm_kfree - &drm_device managed kfree()
+ * @dev: DRM device
+ * @data: memory allocation to be freed
+ *
+ * This is a &drm_device managed version of kfree() which can be used to
+ * release memory allocated through drmm_kmalloc() or any of its related
+ * functions before the final drm_dev_put() of @dev.
+ */
+void drmm_kfree(struct drm_device *dev, void *data)
+{
+	struct drmres *dr_match = NULL, *dr;
+	unsigned long flags;
+
+	if (!data)
+		return;
+
+	spin_lock_irqsave(&dev->managed.lock, flags);
+	list_for_each_entry(dr, &dev->managed.resources, node.entry) {
+		if (dr->data == data) {
+			dr_match = dr;
+			del_dr(dev, dr_match);
+			break;
+		}
+	}
+	spin_unlock_irqrestore(&dev->managed.lock, flags);
+
+	if (WARN_ON(!dr_match))
+		return;
+
+	free_dr(dr_match);
+}
+EXPORT_SYMBOL(drmm_kfree);