// 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/mutex.h>
#include <linux/slab.h>
#include <linux/spinlock.h>
#include <drm/drm_device.h>
#include <drm/drm_print.h>
#include "drm_internal.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 devm_drm_dev_alloc().
*
* 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_DMA_MINALIGN for data[] which will force the same
* alignment for struct drmres when allocated by kmalloc().
*/
u8 __aligned(ARCH_DMA_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);
}
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;
}
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_release_action - release a managed action from a &drm_device
* @dev: DRM device
* @action: function which would be called when @dev is released
* @data: opaque pointer, passed to @action
*
* This function calls the @action previously added by drmm_add_action()
* immediately.
* The @action is removed from the list of cleanup actions for @dev,
* which means that it won't be called in the final drm_dev_put().
*/
void drmm_release_action(struct drm_device *dev,
drmres_release_t action,
void *data)
{
struct drmres *dr_match = NULL, *dr;
unsigned long flags;
spin_lock_irqsave(&dev->managed.lock, flags);
list_for_each_entry_reverse(dr, &dev->managed.resources, node.entry) {
if (dr->node.release == action) {
if (!data || *(void **)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;
action(dev, data);
free_dr(dr_match);
}
EXPORT_SYMBOL(drmm_release_action);
/**
* 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);
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);
void __drmm_mutex_release(struct drm_device *dev, void *res)
{
struct mutex *lock = res;
mutex_destroy(lock);
}
EXPORT_SYMBOL(__drmm_mutex_release);
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