1// SPDX-License-Identifier: GPL-2.0
2/*
3 * Copyright (C) 2020 Intel
4 *
5 * Based on drivers/base/devres.c
6 */
7
8#include <drm/drm_managed.h>
9
10#include <linux/export.h>
11#include <linux/list.h>
12#include <linux/mutex.h>
13#include <linux/slab.h>
14#include <linux/spinlock.h>
15
16#include <drm/drm_device.h>
17#include <drm/drm_print.h>
18
19#include "drm_internal.h"
20
21/**
22 * DOC: managed resources
23 *
24 * Inspired by struct &device managed resources, but tied to the lifetime of
25 * struct &drm_device, which can outlive the underlying physical device, usually
26 * when userspace has some open files and other handles to resources still open.
27 *
28 * Release actions can be added with drmm_add_action(), memory allocations can
29 * be done directly with drmm_kmalloc() and the related functions. Everything
30 * will be released on the final drm_dev_put() in reverse order of how the
31 * release actions have been added and memory has been allocated since driver
32 * loading started with devm_drm_dev_alloc().
33 *
34 * Note that release actions and managed memory can also be added and removed
35 * during the lifetime of the driver, all the functions are fully concurrent
36 * safe. But it is recommended to use managed resources only for resources that
37 * change rarely, if ever, during the lifetime of the &drm_device instance.
38 */
39
40struct drmres_node {
41 struct list_head entry;
42 drmres_release_t release;
43 const char *name;
44 size_t size;
45};
46
47struct drmres {
48 struct drmres_node node;
49 /*
50 * Some archs want to perform DMA into kmalloc caches
51 * and need a guaranteed alignment larger than
52 * the alignment of a 64-bit integer.
53 * Thus we use ARCH_DMA_MINALIGN for data[] which will force the same
54 * alignment for struct drmres when allocated by kmalloc().
55 */
56 u8 __aligned(ARCH_DMA_MINALIGN) data[];
57};
58
59static void free_dr(struct drmres *dr)
60{
61 kfree_const(x: dr->node.name);
62 kfree(objp: dr);
63}
64
65void drm_managed_release(struct drm_device *dev)
66{
67 struct drmres *dr, *tmp;
68
69 drm_dbg_drmres(dev, "drmres release begin\n");
70 list_for_each_entry_safe(dr, tmp, &dev->managed.resources, node.entry) {
71 drm_dbg_drmres(dev, "REL %p %s (%zu bytes)\n",
72 dr, dr->node.name, dr->node.size);
73
74 if (dr->node.release)
75 dr->node.release(dev, dr->node.size ? *(void **)&dr->data : NULL);
76
77 list_del(entry: &dr->node.entry);
78 free_dr(dr);
79 }
80 drm_dbg_drmres(dev, "drmres release end\n");
81}
82
83/*
84 * Always inline so that kmalloc_track_caller tracks the actual interesting
85 * caller outside of drm_managed.c.
86 */
87static __always_inline struct drmres * alloc_dr(drmres_release_t release,
88 size_t size, gfp_t gfp, int nid)
89{
90 size_t tot_size;
91 struct drmres *dr;
92
93 /* We must catch any near-SIZE_MAX cases that could overflow. */
94 if (unlikely(check_add_overflow(sizeof(*dr), size, &tot_size)))
95 return NULL;
96
97 dr = kmalloc_node_track_caller(tot_size, gfp, nid);
98 if (unlikely(!dr))
99 return NULL;
100
101 memset(dr, 0, offsetof(struct drmres, data));
102
103 INIT_LIST_HEAD(list: &dr->node.entry);
104 dr->node.release = release;
105 dr->node.size = size;
106
107 return dr;
108}
109
110static void del_dr(struct drm_device *dev, struct drmres *dr)
111{
112 list_del_init(entry: &dr->node.entry);
113
114 drm_dbg_drmres(dev, "DEL %p %s (%lu bytes)\n",
115 dr, dr->node.name, (unsigned long) dr->node.size);
116}
117
118static void add_dr(struct drm_device *dev, struct drmres *dr)
119{
120 unsigned long flags;
121
122 spin_lock_irqsave(&dev->managed.lock, flags);
123 list_add(new: &dr->node.entry, head: &dev->managed.resources);
124 spin_unlock_irqrestore(lock: &dev->managed.lock, flags);
125
126 drm_dbg_drmres(dev, "ADD %p %s (%lu bytes)\n",
127 dr, dr->node.name, (unsigned long) dr->node.size);
128}
129
130void drmm_add_final_kfree(struct drm_device *dev, void *container)
131{
132 WARN_ON(dev->managed.final_kfree);
133 WARN_ON(dev < (struct drm_device *) container);
134 WARN_ON(dev + 1 > (struct drm_device *) (container + ksize(container)));
135 dev->managed.final_kfree = container;
136}
137
138int __drmm_add_action(struct drm_device *dev,
139 drmres_release_t action,
140 void *data, const char *name)
141{
142 struct drmres *dr;
143 void **void_ptr;
144
145 dr = alloc_dr(release: action, size: data ? sizeof(void*) : 0,
146 GFP_KERNEL | __GFP_ZERO,
147 nid: dev_to_node(dev: dev->dev));
148 if (!dr) {
149 drm_dbg_drmres(dev, "failed to add action %s for %p\n",
150 name, data);
151 return -ENOMEM;
152 }
153
154 dr->node.name = kstrdup_const(s: name, GFP_KERNEL);
155 if (data) {
156 void_ptr = (void **)&dr->data;
157 *void_ptr = data;
158 }
159
160 add_dr(dev, dr);
161
162 return 0;
163}
164EXPORT_SYMBOL(__drmm_add_action);
165
166int __drmm_add_action_or_reset(struct drm_device *dev,
167 drmres_release_t action,
168 void *data, const char *name)
169{
170 int ret;
171
172 ret = __drmm_add_action(dev, action, data, name);
173 if (ret)
174 action(dev, data);
175
176 return ret;
177}
178EXPORT_SYMBOL(__drmm_add_action_or_reset);
179
180/**
181 * drmm_release_action - release a managed action from a &drm_device
182 * @dev: DRM device
183 * @action: function which would be called when @dev is released
184 * @data: opaque pointer, passed to @action
185 *
186 * This function calls the @action previously added by drmm_add_action()
187 * immediately.
188 * The @action is removed from the list of cleanup actions for @dev,
189 * which means that it won't be called in the final drm_dev_put().
190 */
191void drmm_release_action(struct drm_device *dev,
192 drmres_release_t action,
193 void *data)
194{
195 struct drmres *dr_match = NULL, *dr;
196 unsigned long flags;
197
198 spin_lock_irqsave(&dev->managed.lock, flags);
199 list_for_each_entry_reverse(dr, &dev->managed.resources, node.entry) {
200 if (dr->node.release == action) {
201 if (!data || *(void **)dr->data == data) {
202 dr_match = dr;
203 del_dr(dev, dr: dr_match);
204 break;
205 }
206 }
207 }
208 spin_unlock_irqrestore(lock: &dev->managed.lock, flags);
209
210 if (WARN_ON(!dr_match))
211 return;
212
213 action(dev, data);
214
215 free_dr(dr: dr_match);
216}
217EXPORT_SYMBOL(drmm_release_action);
218
219/**
220 * drmm_kmalloc - &drm_device managed kmalloc()
221 * @dev: DRM device
222 * @size: size of the memory allocation
223 * @gfp: GFP allocation flags
224 *
225 * This is a &drm_device managed version of kmalloc(). The allocated memory is
226 * automatically freed on the final drm_dev_put(). Memory can also be freed
227 * before the final drm_dev_put() by calling drmm_kfree().
228 */
229void *drmm_kmalloc(struct drm_device *dev, size_t size, gfp_t gfp)
230{
231 struct drmres *dr;
232
233 dr = alloc_dr(NULL, size, gfp, nid: dev_to_node(dev: dev->dev));
234 if (!dr) {
235 drm_dbg_drmres(dev, "failed to allocate %zu bytes, %u flags\n",
236 size, gfp);
237 return NULL;
238 }
239 dr->node.name = kstrdup_const(s: "kmalloc", gfp);
240
241 add_dr(dev, dr);
242
243 return dr->data;
244}
245EXPORT_SYMBOL(drmm_kmalloc);
246
247/**
248 * drmm_kstrdup - &drm_device managed kstrdup()
249 * @dev: DRM device
250 * @s: 0-terminated string to be duplicated
251 * @gfp: GFP allocation flags
252 *
253 * This is a &drm_device managed version of kstrdup(). The allocated memory is
254 * automatically freed on the final drm_dev_put() and works exactly like a
255 * memory allocation obtained by drmm_kmalloc().
256 */
257char *drmm_kstrdup(struct drm_device *dev, const char *s, gfp_t gfp)
258{
259 size_t size;
260 char *buf;
261
262 if (!s)
263 return NULL;
264
265 size = strlen(s) + 1;
266 buf = drmm_kmalloc(dev, size, gfp);
267 if (buf)
268 memcpy(buf, s, size);
269 return buf;
270}
271EXPORT_SYMBOL_GPL(drmm_kstrdup);
272
273/**
274 * drmm_kfree - &drm_device managed kfree()
275 * @dev: DRM device
276 * @data: memory allocation to be freed
277 *
278 * This is a &drm_device managed version of kfree() which can be used to
279 * release memory allocated through drmm_kmalloc() or any of its related
280 * functions before the final drm_dev_put() of @dev.
281 */
282void drmm_kfree(struct drm_device *dev, void *data)
283{
284 struct drmres *dr_match = NULL, *dr;
285 unsigned long flags;
286
287 if (!data)
288 return;
289
290 spin_lock_irqsave(&dev->managed.lock, flags);
291 list_for_each_entry(dr, &dev->managed.resources, node.entry) {
292 if (dr->data == data) {
293 dr_match = dr;
294 del_dr(dev, dr: dr_match);
295 break;
296 }
297 }
298 spin_unlock_irqrestore(lock: &dev->managed.lock, flags);
299
300 if (WARN_ON(!dr_match))
301 return;
302
303 free_dr(dr: dr_match);
304}
305EXPORT_SYMBOL(drmm_kfree);
306
307void __drmm_mutex_release(struct drm_device *dev, void *res)
308{
309 struct mutex *lock = res;
310
311 mutex_destroy(lock);
312}
313EXPORT_SYMBOL(__drmm_mutex_release);
314
315void __drmm_workqueue_release(struct drm_device *device, void *res)
316{
317 struct workqueue_struct *wq = res;
318
319 destroy_workqueue(wq);
320}
321EXPORT_SYMBOL(__drmm_workqueue_release);
322

source code of linux/drivers/gpu/drm/drm_managed.c