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28 * Authors: Thomas Hellstrom <thellstrom-at-vmware-dot-com>
30 /** @file ttm_object.h
32 * Base- and reference object implementation for the various
33 * ttm objects. Implements reference counting, minimal security checks
34 * and release on file close.
37 #ifndef _TTM_OBJECT_H_
38 #define _TTM_OBJECT_H_
40 #include <linux/dma-buf.h>
41 #include <linux/kref.h>
42 #include <linux/list.h>
43 #include <linux/rcupdate.h>
45 #include <drm/drm_hashtab.h>
47 #include "ttm_memory.h"
52 * Describes what type of reference a ref object holds.
54 * TTM_REF_USAGE is a simple refcount on a base object.
56 * TTM_REF_SYNCCPU_READ is a SYNCCPU_READ reference on a
59 * TTM_REF_SYNCCPU_WRITE is a SYNCCPU_WRITE reference on a
67 TTM_REF_SYNCCPU_WRITE,
72 * enum ttm_object_type
74 * One entry per ttm object type.
75 * Device-specific types should use the
76 * ttm_driver_typex types.
79 enum ttm_object_type {
84 ttm_driver_type0 = 256,
92 struct ttm_object_file;
93 struct ttm_object_device;
96 * struct ttm_base_object
98 * @hash: hash entry for the per-device object hash.
99 * @type: derived type this object is base class for.
100 * @shareable: Other ttm_object_files can access this object.
102 * @tfile: Pointer to ttm_object_file of the creator.
103 * NULL if the object was not created by a user request.
106 * @refcount: Number of references to this object, not
107 * including the hash entry. A reference to a base object can
108 * only be held by a ref object.
110 * @refcount_release: A function to be called when there are
111 * no more references to this object. This function should
112 * destroy the object (or make sure destruction eventually happens),
113 * and when it is called, the object has
114 * already been taken out of the per-device hash. The parameter
115 * "base" should be set to NULL by the function.
117 * @ref_obj_release: A function to be called when a reference object
118 * with another ttm_ref_type than TTM_REF_USAGE is deleted.
119 * This function may, for example, release a lock held by a user-space
122 * This struct is intended to be used as a base struct for objects that
123 * are visible to user-space. It provides a global name, race-safe
124 * access and refcounting, minimal access contol and hooks for unref actions.
127 struct ttm_base_object {
128 struct rcu_head rhead;
129 struct ttm_object_file *tfile;
130 struct kref refcount;
131 void (*refcount_release) (struct ttm_base_object **base);
132 void (*ref_obj_release) (struct ttm_base_object *base,
133 enum ttm_ref_type ref_type);
135 enum ttm_object_type object_type;
141 * struct ttm_prime_object - Modified base object that is prime-aware
143 * @base: struct ttm_base_object that we derive from
144 * @mutex: Mutex protecting the @dma_buf member.
145 * @size: Size of the dma_buf associated with this object
146 * @real_type: Type of the underlying object. Needed since we're setting
147 * the value of @base::object_type to ttm_prime_type
148 * @dma_buf: Non ref-coutned pointer to a struct dma_buf created from this
150 * @refcount_release: The underlying object's release method. Needed since
151 * we set @base::refcount_release to our own release method.
154 struct ttm_prime_object {
155 struct ttm_base_object base;
158 enum ttm_object_type real_type;
159 struct dma_buf *dma_buf;
160 void (*refcount_release) (struct ttm_base_object **);
164 * ttm_base_object_init
166 * @tfile: Pointer to a struct ttm_object_file.
167 * @base: The struct ttm_base_object to initialize.
168 * @shareable: This object is shareable with other applcations.
169 * (different @tfile pointers.)
170 * @type: The object type.
171 * @refcount_release: See the struct ttm_base_object description.
172 * @ref_obj_release: See the struct ttm_base_object description.
174 * Initializes a struct ttm_base_object.
177 extern int ttm_base_object_init(struct ttm_object_file *tfile,
178 struct ttm_base_object *base,
180 enum ttm_object_type type,
181 void (*refcount_release) (struct ttm_base_object
183 void (*ref_obj_release) (struct ttm_base_object
189 * ttm_base_object_lookup
191 * @tfile: Pointer to a struct ttm_object_file.
194 * Looks up a struct ttm_base_object with the key @key.
197 extern struct ttm_base_object *ttm_base_object_lookup(struct ttm_object_file
198 *tfile, uint32_t key);
201 * ttm_base_object_lookup_for_ref
203 * @tdev: Pointer to a struct ttm_object_device.
206 * Looks up a struct ttm_base_object with the key @key.
207 * This function should only be used when the struct tfile associated with the
208 * caller doesn't yet have a reference to the base object.
211 extern struct ttm_base_object *
212 ttm_base_object_lookup_for_ref(struct ttm_object_device *tdev, uint32_t key);
215 * ttm_base_object_unref
217 * @p_base: Pointer to a pointer referencing a struct ttm_base_object.
219 * Decrements the base object refcount and clears the pointer pointed to by
223 extern void ttm_base_object_unref(struct ttm_base_object **p_base);
226 * ttm_ref_object_add.
228 * @tfile: A struct ttm_object_file representing the application owning the
230 * @base: The base object to reference.
231 * @ref_type: The type of reference.
232 * @existed: Upon completion, indicates that an identical reference object
233 * already existed, and the refcount was upped on that object instead.
234 * @require_existed: Fail with -EPERM if an identical ref object didn't
237 * Checks that the base object is shareable and adds a ref object to it.
239 * Adding a ref object to a base object is basically like referencing the
240 * base object, but a user-space application holds the reference. When the
241 * file corresponding to @tfile is closed, all its reference objects are
242 * deleted. A reference object can have different types depending on what
243 * it's intended for. It can be refcounting to prevent object destruction,
244 * When user-space takes a lock, it can add a ref object to that lock to
245 * make sure the lock is released if the application dies. A ref object
246 * will hold a single reference on a base object.
248 extern int ttm_ref_object_add(struct ttm_object_file *tfile,
249 struct ttm_base_object *base,
250 enum ttm_ref_type ref_type, bool *existed,
251 bool require_existed);
253 extern bool ttm_ref_object_exists(struct ttm_object_file *tfile,
254 struct ttm_base_object *base);
257 * ttm_ref_object_base_unref
259 * @key: Key representing the base object.
260 * @ref_type: Ref type of the ref object to be dereferenced.
262 * Unreference a ref object with type @ref_type
263 * on the base object identified by @key. If there are no duplicate
264 * references, the ref object will be destroyed and the base object
265 * will be unreferenced.
267 extern int ttm_ref_object_base_unref(struct ttm_object_file *tfile,
269 enum ttm_ref_type ref_type);
272 * ttm_object_file_init - initialize a struct ttm_object file
274 * @tdev: A struct ttm_object device this file is initialized on.
275 * @hash_order: Order of the hash table used to hold the reference objects.
277 * This is typically called by the file_ops::open function.
280 extern struct ttm_object_file *ttm_object_file_init(struct ttm_object_device
282 unsigned int hash_order);
285 * ttm_object_file_release - release data held by a ttm_object_file
287 * @p_tfile: Pointer to pointer to the ttm_object_file object to release.
288 * *p_tfile will be set to NULL by this function.
290 * Releases all data associated by a ttm_object_file.
291 * Typically called from file_ops::release. The caller must
292 * ensure that there are no concurrent users of tfile.
295 extern void ttm_object_file_release(struct ttm_object_file **p_tfile);
298 * ttm_object device init - initialize a struct ttm_object_device
300 * @mem_glob: struct ttm_mem_global for memory accounting.
301 * @hash_order: Order of hash table used to hash the base objects.
302 * @ops: DMA buf ops for prime objects of this device.
304 * This function is typically called on device initialization to prepare
305 * data structures needed for ttm base and ref objects.
308 extern struct ttm_object_device *
309 ttm_object_device_init(struct ttm_mem_global *mem_glob,
310 unsigned int hash_order,
311 const struct dma_buf_ops *ops);
314 * ttm_object_device_release - release data held by a ttm_object_device
316 * @p_tdev: Pointer to pointer to the ttm_object_device object to release.
317 * *p_tdev will be set to NULL by this function.
319 * Releases all data associated by a ttm_object_device.
320 * Typically called from driver::unload before the destruction of the
321 * device private data structure.
324 extern void ttm_object_device_release(struct ttm_object_device **p_tdev);
326 #define ttm_base_object_kfree(__object, __base)\
327 kfree_rcu(__object, __base.rhead)
329 extern int ttm_prime_object_init(struct ttm_object_file *tfile,
331 struct ttm_prime_object *prime,
333 enum ttm_object_type type,
334 void (*refcount_release)
335 (struct ttm_base_object **),
336 void (*ref_obj_release)
337 (struct ttm_base_object *,
338 enum ttm_ref_type ref_type));
340 static inline enum ttm_object_type
341 ttm_base_object_type(struct ttm_base_object *base)
343 return (base->object_type == ttm_prime_type) ?
344 container_of(base, struct ttm_prime_object, base)->real_type :
347 extern int ttm_prime_fd_to_handle(struct ttm_object_file *tfile,
348 int fd, u32 *handle);
349 extern int ttm_prime_handle_to_fd(struct ttm_object_file *tfile,
350 uint32_t handle, uint32_t flags,
353 #define ttm_prime_object_kfree(__obj, __prime) \
354 kfree_rcu(__obj, __prime.base.rhead)
357 * Extra memory required by the base object's idr storage, which is allocated
358 * separately from the base object itself. We estimate an on-average 128 bytes
361 #define TTM_OBJ_EXTRA_SIZE 128
363 struct ttm_base_object *
364 ttm_base_object_noref_lookup(struct ttm_object_file *tfile, uint32_t key);
367 * ttm_base_object_noref_release - release a base object pointer looked up
370 * Releases a base object pointer looked up with ttm_base_object_noref_lookup().
372 static inline void ttm_base_object_noref_release(void)