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1 : /* SPDX-License-Identifier: GPL-2.0 */
2 : /*
3 : * KUnit resource API for test managed resources (allocations, etc.).
4 : *
5 : * Copyright (C) 2022, Google LLC.
6 : * Author: Daniel Latypov <dlatypov@google.com>
7 : */
8 :
9 : #ifndef _KUNIT_RESOURCE_H
10 : #define _KUNIT_RESOURCE_H
11 :
12 : #include <kunit/test.h>
13 :
14 : #include <linux/kref.h>
15 : #include <linux/list.h>
16 : #include <linux/slab.h>
17 : #include <linux/spinlock.h>
18 :
19 : struct kunit_resource;
20 :
21 : typedef int (*kunit_resource_init_t)(struct kunit_resource *, void *);
22 : typedef void (*kunit_resource_free_t)(struct kunit_resource *);
23 :
24 : /**
25 : * struct kunit_resource - represents a *test managed resource*
26 : * @data: for the user to store arbitrary data.
27 : * @name: optional name
28 : * @free: a user supplied function to free the resource.
29 : *
30 : * Represents a *test managed resource*, a resource which will automatically be
31 : * cleaned up at the end of a test case. This cleanup is performed by the 'free'
32 : * function. The struct kunit_resource itself is freed automatically with
33 : * kfree() if it was allocated by KUnit (e.g., by kunit_alloc_resource()), but
34 : * must be freed by the user otherwise.
35 : *
36 : * Resources are reference counted so if a resource is retrieved via
37 : * kunit_alloc_and_get_resource() or kunit_find_resource(), we need
38 : * to call kunit_put_resource() to reduce the resource reference count
39 : * when finished with it. Note that kunit_alloc_resource() does not require a
40 : * kunit_resource_put() because it does not retrieve the resource itself.
41 : *
42 : * Example:
43 : *
44 : * .. code-block:: c
45 : *
46 : * struct kunit_kmalloc_params {
47 : * size_t size;
48 : * gfp_t gfp;
49 : * };
50 : *
51 : * static int kunit_kmalloc_init(struct kunit_resource *res, void *context)
52 : * {
53 : * struct kunit_kmalloc_params *params = context;
54 : * res->data = kmalloc(params->size, params->gfp);
55 : *
56 : * if (!res->data)
57 : * return -ENOMEM;
58 : *
59 : * return 0;
60 : * }
61 : *
62 : * static void kunit_kmalloc_free(struct kunit_resource *res)
63 : * {
64 : * kfree(res->data);
65 : * }
66 : *
67 : * void *kunit_kmalloc(struct kunit *test, size_t size, gfp_t gfp)
68 : * {
69 : * struct kunit_kmalloc_params params;
70 : *
71 : * params.size = size;
72 : * params.gfp = gfp;
73 : *
74 : * return kunit_alloc_resource(test, kunit_kmalloc_init,
75 : * kunit_kmalloc_free, ¶ms);
76 : * }
77 : *
78 : * Resources can also be named, with lookup/removal done on a name
79 : * basis also. kunit_add_named_resource(), kunit_find_named_resource()
80 : * and kunit_destroy_named_resource(). Resource names must be
81 : * unique within the test instance.
82 : */
83 : struct kunit_resource {
84 : void *data;
85 : const char *name;
86 : kunit_resource_free_t free;
87 :
88 : /* private: internal use only. */
89 : struct kref refcount;
90 : struct list_head node;
91 : bool should_kfree;
92 : };
93 :
94 : /**
95 : * kunit_get_resource() - Hold resource for use. Should not need to be used
96 : * by most users as we automatically get resources
97 : * retrieved by kunit_find_resource*().
98 : * @res: resource
99 : */
100 : static inline void kunit_get_resource(struct kunit_resource *res)
101 : {
102 0 : kref_get(&res->refcount);
103 : }
104 :
105 : /*
106 : * Called when refcount reaches zero via kunit_put_resource();
107 : * should not be called directly.
108 : */
109 312 : static inline void kunit_release_resource(struct kref *kref)
110 : {
111 312 : struct kunit_resource *res = container_of(kref, struct kunit_resource,
112 : refcount);
113 :
114 312 : if (res->free)
115 312 : res->free(res);
116 :
117 : /* 'res' is valid here, as if should_kfree is set, res->free may not free
118 : * 'res' itself, just res->data
119 : */
120 312 : if (res->should_kfree)
121 312 : kfree(res);
122 312 : }
123 :
124 : /**
125 : * kunit_put_resource() - When caller is done with retrieved resource,
126 : * kunit_put_resource() should be called to drop
127 : * reference count. The resource list maintains
128 : * a reference count on resources, so if no users
129 : * are utilizing a resource and it is removed from
130 : * the resource list, it will be freed via the
131 : * associated free function (if any). Only
132 : * needs to be used if we alloc_and_get() or
133 : * find() resource.
134 : * @res: resource
135 : */
136 : static inline void kunit_put_resource(struct kunit_resource *res)
137 : {
138 312 : kref_put(&res->refcount, kunit_release_resource);
139 : }
140 :
141 : /**
142 : * __kunit_add_resource() - Internal helper to add a resource.
143 : *
144 : * res->should_kfree is not initialised.
145 : * @test: The test context object.
146 : * @init: a user-supplied function to initialize the result (if needed). If
147 : * none is supplied, the resource data value is simply set to @data.
148 : * If an init function is supplied, @data is passed to it instead.
149 : * @free: a user-supplied function to free the resource (if needed).
150 : * @res: The resource.
151 : * @data: value to pass to init function or set in resource data field.
152 : */
153 : int __kunit_add_resource(struct kunit *test,
154 : kunit_resource_init_t init,
155 : kunit_resource_free_t free,
156 : struct kunit_resource *res,
157 : void *data);
158 :
159 : /**
160 : * kunit_add_resource() - Add a *test managed resource*.
161 : * @test: The test context object.
162 : * @init: a user-supplied function to initialize the result (if needed). If
163 : * none is supplied, the resource data value is simply set to @data.
164 : * If an init function is supplied, @data is passed to it instead.
165 : * @free: a user-supplied function to free the resource (if needed).
166 : * @res: The resource.
167 : * @data: value to pass to init function or set in resource data field.
168 : */
169 : static inline int kunit_add_resource(struct kunit *test,
170 : kunit_resource_init_t init,
171 : kunit_resource_free_t free,
172 : struct kunit_resource *res,
173 : void *data)
174 : {
175 : res->should_kfree = false;
176 : return __kunit_add_resource(test, init, free, res, data);
177 : }
178 :
179 : static inline struct kunit_resource *
180 : kunit_find_named_resource(struct kunit *test, const char *name);
181 :
182 : /**
183 : * kunit_add_named_resource() - Add a named *test managed resource*.
184 : * @test: The test context object.
185 : * @init: a user-supplied function to initialize the resource data, if needed.
186 : * @free: a user-supplied function to free the resource data, if needed.
187 : * @res: The resource.
188 : * @name: name to be set for resource.
189 : * @data: value to pass to init function or set in resource data field.
190 : */
191 : static inline int kunit_add_named_resource(struct kunit *test,
192 : kunit_resource_init_t init,
193 : kunit_resource_free_t free,
194 : struct kunit_resource *res,
195 : const char *name,
196 : void *data)
197 : {
198 : struct kunit_resource *existing;
199 :
200 : if (!name)
201 : return -EINVAL;
202 :
203 : existing = kunit_find_named_resource(test, name);
204 : if (existing) {
205 : kunit_put_resource(existing);
206 : return -EEXIST;
207 : }
208 :
209 : res->name = name;
210 : res->should_kfree = false;
211 :
212 : return __kunit_add_resource(test, init, free, res, data);
213 : }
214 :
215 : /**
216 : * kunit_alloc_and_get_resource() - Allocates and returns a *test managed resource*.
217 : * @test: The test context object.
218 : * @init: a user supplied function to initialize the resource.
219 : * @free: a user supplied function to free the resource (if needed).
220 : * @internal_gfp: gfp to use for internal allocations, if unsure, use GFP_KERNEL
221 : * @context: for the user to pass in arbitrary data to the init function.
222 : *
223 : * Allocates a *test managed resource*, a resource which will automatically be
224 : * cleaned up at the end of a test case. See &struct kunit_resource for an
225 : * example.
226 : *
227 : * This is effectively identical to kunit_alloc_resource, but returns the
228 : * struct kunit_resource pointer, not just the 'data' pointer. It therefore
229 : * also increments the resource's refcount, so kunit_put_resource() should be
230 : * called when you've finished with it.
231 : *
232 : * Note: KUnit needs to allocate memory for a kunit_resource object. You must
233 : * specify an @internal_gfp that is compatible with the use context of your
234 : * resource.
235 : */
236 : static inline struct kunit_resource *
237 : kunit_alloc_and_get_resource(struct kunit *test,
238 : kunit_resource_init_t init,
239 : kunit_resource_free_t free,
240 : gfp_t internal_gfp,
241 : void *context)
242 : {
243 : struct kunit_resource *res;
244 : int ret;
245 :
246 : res = kzalloc(sizeof(*res), internal_gfp);
247 : if (!res)
248 : return NULL;
249 :
250 : res->should_kfree = true;
251 :
252 : ret = __kunit_add_resource(test, init, free, res, context);
253 : if (!ret) {
254 : /*
255 : * bump refcount for get; kunit_resource_put() should be called
256 : * when done.
257 : */
258 : kunit_get_resource(res);
259 : return res;
260 : }
261 : return NULL;
262 : }
263 :
264 : /**
265 : * kunit_alloc_resource() - Allocates a *test managed resource*.
266 : * @test: The test context object.
267 : * @init: a user supplied function to initialize the resource.
268 : * @free: a user supplied function to free the resource (if needed).
269 : * @internal_gfp: gfp to use for internal allocations, if unsure, use GFP_KERNEL
270 : * @context: for the user to pass in arbitrary data to the init function.
271 : *
272 : * Allocates a *test managed resource*, a resource which will automatically be
273 : * cleaned up at the end of a test case. See &struct kunit_resource for an
274 : * example.
275 : *
276 : * Note: KUnit needs to allocate memory for a kunit_resource object. You must
277 : * specify an @internal_gfp that is compatible with the use context of your
278 : * resource.
279 : */
280 312 : static inline void *kunit_alloc_resource(struct kunit *test,
281 : kunit_resource_init_t init,
282 : kunit_resource_free_t free,
283 : gfp_t internal_gfp,
284 : void *context)
285 : {
286 : struct kunit_resource *res;
287 :
288 312 : res = kzalloc(sizeof(*res), internal_gfp);
289 312 : if (!res)
290 : return NULL;
291 :
292 312 : res->should_kfree = true;
293 312 : if (!__kunit_add_resource(test, init, free, res, context))
294 312 : return res->data;
295 :
296 : return NULL;
297 : }
298 :
299 : typedef bool (*kunit_resource_match_t)(struct kunit *test,
300 : struct kunit_resource *res,
301 : void *match_data);
302 :
303 : /**
304 : * kunit_resource_name_match() - Match a resource with the same name.
305 : * @test: Test case to which the resource belongs.
306 : * @res: The resource.
307 : * @match_name: The name to match against.
308 : */
309 0 : static inline bool kunit_resource_name_match(struct kunit *test,
310 : struct kunit_resource *res,
311 : void *match_name)
312 : {
313 0 : return res->name && strcmp(res->name, match_name) == 0;
314 : }
315 :
316 : /**
317 : * kunit_find_resource() - Find a resource using match function/data.
318 : * @test: Test case to which the resource belongs.
319 : * @match: match function to be applied to resources/match data.
320 : * @match_data: data to be used in matching.
321 : */
322 : static inline struct kunit_resource *
323 0 : kunit_find_resource(struct kunit *test,
324 : kunit_resource_match_t match,
325 : void *match_data)
326 : {
327 0 : struct kunit_resource *res, *found = NULL;
328 : unsigned long flags;
329 :
330 0 : spin_lock_irqsave(&test->lock, flags);
331 :
332 0 : list_for_each_entry_reverse(res, &test->resources, node) {
333 0 : if (match(test, res, (void *)match_data)) {
334 0 : found = res;
335 : kunit_get_resource(found);
336 : break;
337 : }
338 : }
339 :
340 0 : spin_unlock_irqrestore(&test->lock, flags);
341 :
342 0 : return found;
343 : }
344 :
345 : /**
346 : * kunit_find_named_resource() - Find a resource using match name.
347 : * @test: Test case to which the resource belongs.
348 : * @name: match name.
349 : */
350 : static inline struct kunit_resource *
351 : kunit_find_named_resource(struct kunit *test,
352 : const char *name)
353 : {
354 0 : return kunit_find_resource(test, kunit_resource_name_match,
355 : (void *)name);
356 : }
357 :
358 : /**
359 : * kunit_destroy_resource() - Find a kunit_resource and destroy it.
360 : * @test: Test case to which the resource belongs.
361 : * @match: Match function. Returns whether a given resource matches @match_data.
362 : * @match_data: Data passed into @match.
363 : *
364 : * RETURNS:
365 : * 0 if kunit_resource is found and freed, -ENOENT if not found.
366 : */
367 : int kunit_destroy_resource(struct kunit *test,
368 : kunit_resource_match_t match,
369 : void *match_data);
370 :
371 : static inline int kunit_destroy_named_resource(struct kunit *test,
372 : const char *name)
373 : {
374 : return kunit_destroy_resource(test, kunit_resource_name_match,
375 : (void *)name);
376 : }
377 :
378 : /**
379 : * kunit_remove_resource() - remove resource from resource list associated with
380 : * test.
381 : * @test: The test context object.
382 : * @res: The resource to be removed.
383 : *
384 : * Note that the resource will not be immediately freed since it is likely
385 : * the caller has a reference to it via alloc_and_get() or find();
386 : * in this case a final call to kunit_put_resource() is required.
387 : */
388 : void kunit_remove_resource(struct kunit *test, struct kunit_resource *res);
389 :
390 : #endif /* _KUNIT_RESOURCE_H */
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