1 /************************************************************************** 2 * 3 * Copyright (c) 2009 VMware, Inc., Palo Alto, CA., USA 4 * All Rights Reserved. 5 * 6 * Permission is hereby granted, free of charge, to any person obtaining a 7 * copy of this software and associated documentation files (the 8 * "Software"), to deal in the Software without restriction, including 9 * without limitation the rights to use, copy, modify, merge, publish, 10 * distribute, sub license, and/or sell copies of the Software, and to 11 * permit persons to whom the Software is furnished to do so, subject to 12 * the following conditions: 13 * 14 * The above copyright notice and this permission notice (including the 15 * next paragraph) shall be included in all copies or substantial portions 16 * of the Software. 17 * 18 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR 19 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, 20 * FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT. IN NO EVENT SHALL 21 * THE COPYRIGHT HOLDERS, AUTHORS AND/OR ITS SUPPLIERS BE LIABLE FOR ANY CLAIM, 22 * DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR 23 * OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE 24 * USE OR OTHER DEALINGS IN THE SOFTWARE. 25 * 26 **************************************************************************/ 27 /* 28 * Authors: Thomas Hellstrom <thellstrom-at-vmware-dot-com> 29 */ 30 /** @file ttm_ref_object.c 31 * 32 * Base- and reference object implementation for the various 33 * ttm objects. Implements reference counting, minimal security checks 34 * and release on file close. 35 */ 36 37 /** 38 * struct ttm_object_file 39 * 40 * @tdev: Pointer to the ttm_object_device. 41 * 42 * @lock: Lock that protects the ref_list list and the 43 * ref_hash hash tables. 44 * 45 * @ref_list: List of ttm_ref_objects to be destroyed at 46 * file release. 47 * 48 * @ref_hash: Hash tables of ref objects, one per ttm_ref_type, 49 * for fast lookup of ref objects given a base object. 50 */ 51 52 #define pr_fmt(fmt) "[TTM] " fmt 53 54 #include <drm/drmP.h> 55 #include <drm/ttm/ttm_object.h> 56 #include <drm/ttm/ttm_module.h> 57 #include <linux/export.h> 58 59 struct ttm_object_file { 60 struct ttm_object_device *tdev; 61 struct lock lock; 62 struct list_head ref_list; 63 struct drm_open_hash ref_hash[TTM_REF_NUM]; 64 struct kref refcount; 65 }; 66 67 /** 68 * struct ttm_object_device 69 * 70 * @object_lock: lock that protects the object_hash hash table. 71 * 72 * @object_hash: hash table for fast lookup of object global names. 73 * 74 * @object_count: Per device object count. 75 * 76 * This is the per-device data structure needed for ttm object management. 77 */ 78 79 struct ttm_object_device { 80 struct lock object_lock; 81 struct drm_open_hash object_hash; 82 atomic_t object_count; 83 struct ttm_mem_global *mem_glob; 84 }; 85 86 /** 87 * struct ttm_ref_object 88 * 89 * @hash: Hash entry for the per-file object reference hash. 90 * 91 * @head: List entry for the per-file list of ref-objects. 92 * 93 * @kref: Ref count. 94 * 95 * @obj: Base object this ref object is referencing. 96 * 97 * @ref_type: Type of ref object. 98 * 99 * This is similar to an idr object, but it also has a hash table entry 100 * that allows lookup with a pointer to the referenced object as a key. In 101 * that way, one can easily detect whether a base object is referenced by 102 * a particular ttm_object_file. It also carries a ref count to avoid creating 103 * multiple ref objects if a ttm_object_file references the same base 104 * object more than once. 105 */ 106 107 struct ttm_ref_object { 108 struct drm_hash_item hash; 109 struct list_head head; 110 struct kref kref; 111 enum ttm_ref_type ref_type; 112 struct ttm_base_object *obj; 113 struct ttm_object_file *tfile; 114 }; 115 116 static inline struct ttm_object_file * 117 ttm_object_file_ref(struct ttm_object_file *tfile) 118 { 119 kref_get(&tfile->refcount); 120 return tfile; 121 } 122 123 static void ttm_object_file_destroy(struct kref *kref) 124 { 125 struct ttm_object_file *tfile = 126 container_of(kref, struct ttm_object_file, refcount); 127 128 kfree(tfile); 129 } 130 131 132 static inline void ttm_object_file_unref(struct ttm_object_file **p_tfile) 133 { 134 struct ttm_object_file *tfile = *p_tfile; 135 136 *p_tfile = NULL; 137 kref_put(&tfile->refcount, ttm_object_file_destroy); 138 } 139 140 141 int ttm_base_object_init(struct ttm_object_file *tfile, 142 struct ttm_base_object *base, 143 bool shareable, 144 enum ttm_object_type object_type, 145 void (*refcount_release) (struct ttm_base_object **), 146 void (*ref_obj_release) (struct ttm_base_object *, 147 enum ttm_ref_type ref_type)) 148 { 149 struct ttm_object_device *tdev = tfile->tdev; 150 int ret; 151 152 base->shareable = shareable; 153 base->tfile = ttm_object_file_ref(tfile); 154 base->refcount_release = refcount_release; 155 base->ref_obj_release = ref_obj_release; 156 base->object_type = object_type; 157 kref_init(&base->refcount); 158 lockinit(&tdev->object_lock, "ttmbao", 0, LK_CANRECURSE); 159 lockmgr(&tdev->object_lock, LK_EXCLUSIVE); 160 ret = drm_ht_just_insert_please(&tdev->object_hash, 161 &base->hash, 162 (unsigned long)base, 31, 0, 0); 163 lockmgr(&tdev->object_lock, LK_RELEASE); 164 if (unlikely(ret != 0)) 165 goto out_err0; 166 167 ret = ttm_ref_object_add(tfile, base, TTM_REF_USAGE, NULL); 168 if (unlikely(ret != 0)) 169 goto out_err1; 170 171 ttm_base_object_unref(&base); 172 173 return 0; 174 out_err1: 175 lockmgr(&tdev->object_lock, LK_EXCLUSIVE); 176 (void)drm_ht_remove_item(&tdev->object_hash, &base->hash); 177 lockmgr(&tdev->object_lock, LK_RELEASE); 178 out_err0: 179 return ret; 180 } 181 EXPORT_SYMBOL(ttm_base_object_init); 182 183 static void ttm_release_base(struct kref *kref) 184 { 185 struct ttm_base_object *base = 186 container_of(kref, struct ttm_base_object, refcount); 187 struct ttm_object_device *tdev = base->tfile->tdev; 188 189 if (atomic_read(&kref->refcount)) { 190 lockmgr(&tdev->object_lock, LK_RELEASE); 191 return; 192 } 193 (void)drm_ht_remove_item(&tdev->object_hash, &base->hash); 194 lockmgr(&tdev->object_lock, LK_RELEASE); 195 196 /* 197 * Note: We don't use synchronize_rcu() here because it's far 198 * too slow. It's up to the user to free the object using 199 * call_rcu() or ttm_base_object_kfree(). 200 */ 201 202 if (base->refcount_release) { 203 ttm_object_file_unref(&base->tfile); 204 base->refcount_release(&base); 205 } 206 } 207 208 void ttm_base_object_unref(struct ttm_base_object **p_base) 209 { 210 struct ttm_base_object *base = *p_base; 211 struct ttm_object_device *tdev = base->tfile->tdev; 212 213 *p_base = NULL; 214 215 lockmgr(&tdev->object_lock, LK_EXCLUSIVE); 216 if (kref_put(&base->refcount, ttm_release_base) == 0) { 217 lockmgr(&tdev->object_lock, LK_RELEASE); 218 } 219 } 220 EXPORT_SYMBOL(ttm_base_object_unref); 221 222 struct ttm_base_object *ttm_base_object_lookup(struct ttm_object_file *tfile, 223 uint32_t key) 224 { 225 struct ttm_object_device *tdev = tfile->tdev; 226 struct ttm_base_object *base; 227 struct drm_hash_item *hash; 228 int ret; 229 230 lockmgr(&tdev->object_lock, LK_EXCLUSIVE); 231 ret = drm_ht_find_item(&tdev->object_hash, key, &hash); 232 233 if (likely(ret == 0)) { 234 base = drm_hash_entry(hash, struct ttm_base_object, hash); 235 ret = kref_get_unless_zero(&base->refcount) ? 0 : -EINVAL; 236 } 237 lockmgr(&tdev->object_lock, LK_RELEASE); 238 239 if (unlikely(ret != 0)) 240 return NULL; 241 242 if (tfile != base->tfile && !base->shareable) { 243 pr_err("Attempted access of non-shareable object %p\n", base); 244 ttm_base_object_unref(&base); 245 return NULL; 246 } 247 248 return base; 249 } 250 EXPORT_SYMBOL(ttm_base_object_lookup); 251 252 int ttm_ref_object_add(struct ttm_object_file *tfile, 253 struct ttm_base_object *base, 254 enum ttm_ref_type ref_type, bool *existed) 255 { 256 struct drm_open_hash *ht = &tfile->ref_hash[ref_type]; 257 struct ttm_ref_object *ref; 258 struct drm_hash_item *hash; 259 struct ttm_mem_global *mem_glob = tfile->tdev->mem_glob; 260 int ret = -EINVAL; 261 262 if (existed != NULL) 263 *existed = true; 264 265 while (ret == -EINVAL) { 266 lockmgr(&tfile->lock, LK_EXCLUSIVE); 267 ret = drm_ht_find_item(ht, base->hash.key, &hash); 268 269 if (ret == 0) { 270 ref = drm_hash_entry(hash, struct ttm_ref_object, hash); 271 kref_get(&ref->kref); 272 lockmgr(&tfile->lock, LK_RELEASE); 273 break; 274 } 275 276 lockmgr(&tfile->lock, LK_RELEASE); 277 ret = ttm_mem_global_alloc(mem_glob, sizeof(*ref), 278 false, false); 279 if (unlikely(ret != 0)) 280 return ret; 281 ref = kmalloc(sizeof(*ref), M_DRM, M_WAITOK); 282 if (unlikely(ref == NULL)) { 283 ttm_mem_global_free(mem_glob, sizeof(*ref)); 284 return -ENOMEM; 285 } 286 287 ref->hash.key = base->hash.key; 288 ref->obj = base; 289 ref->tfile = tfile; 290 ref->ref_type = ref_type; 291 kref_init(&ref->kref); 292 293 lockmgr(&tfile->lock, LK_EXCLUSIVE); 294 ret = drm_ht_insert_item(ht, &ref->hash); 295 296 if (likely(ret == 0)) { 297 list_add_tail(&ref->head, &tfile->ref_list); 298 kref_get(&base->refcount); 299 lockmgr(&tfile->lock, LK_RELEASE); 300 if (existed != NULL) 301 *existed = false; 302 break; 303 } 304 305 lockmgr(&tfile->lock, LK_RELEASE); 306 BUG_ON(ret != -EINVAL); 307 308 ttm_mem_global_free(mem_glob, sizeof(*ref)); 309 kfree(ref); 310 } 311 312 return ret; 313 } 314 EXPORT_SYMBOL(ttm_ref_object_add); 315 316 static void ttm_ref_object_release(struct kref *kref) 317 { 318 struct ttm_ref_object *ref = 319 container_of(kref, struct ttm_ref_object, kref); 320 struct ttm_base_object *base = ref->obj; 321 struct ttm_object_file *tfile = ref->tfile; 322 struct drm_open_hash *ht; 323 struct ttm_mem_global *mem_glob = tfile->tdev->mem_glob; 324 325 ht = &tfile->ref_hash[ref->ref_type]; 326 (void)drm_ht_remove_item(ht, &ref->hash); 327 list_del(&ref->head); 328 lockmgr(&tfile->lock, LK_RELEASE); 329 330 if (ref->ref_type != TTM_REF_USAGE && base->ref_obj_release) 331 base->ref_obj_release(base, ref->ref_type); 332 333 ttm_base_object_unref(&ref->obj); 334 ttm_mem_global_free(mem_glob, sizeof(*ref)); 335 kfree(ref); 336 lockmgr(&tfile->lock, LK_EXCLUSIVE); 337 } 338 339 int ttm_ref_object_base_unref(struct ttm_object_file *tfile, 340 unsigned long key, enum ttm_ref_type ref_type) 341 { 342 struct drm_open_hash *ht = &tfile->ref_hash[ref_type]; 343 struct ttm_ref_object *ref; 344 struct drm_hash_item *hash; 345 int ret; 346 347 lockmgr(&tfile->lock, LK_EXCLUSIVE); 348 ret = drm_ht_find_item(ht, key, &hash); 349 if (unlikely(ret != 0)) { 350 lockmgr(&tfile->lock, LK_RELEASE); 351 return -EINVAL; 352 } 353 ref = drm_hash_entry(hash, struct ttm_ref_object, hash); 354 kref_put(&ref->kref, ttm_ref_object_release); 355 lockmgr(&tfile->lock, LK_RELEASE); 356 return 0; 357 } 358 EXPORT_SYMBOL(ttm_ref_object_base_unref); 359 360 void ttm_object_file_release(struct ttm_object_file **p_tfile) 361 { 362 struct ttm_ref_object *ref; 363 struct list_head *list; 364 unsigned int i; 365 struct ttm_object_file *tfile = *p_tfile; 366 367 *p_tfile = NULL; 368 lockmgr(&tfile->lock, LK_EXCLUSIVE); 369 370 /* 371 * Since we release the lock within the loop, we have to 372 * restart it from the beginning each time. 373 */ 374 375 while (!list_empty(&tfile->ref_list)) { 376 list = tfile->ref_list.next; 377 ref = list_entry(list, struct ttm_ref_object, head); 378 ttm_ref_object_release(&ref->kref); 379 } 380 381 for (i = 0; i < TTM_REF_NUM; ++i) 382 drm_ht_remove(&tfile->ref_hash[i]); 383 384 lockmgr(&tfile->lock, LK_RELEASE); 385 ttm_object_file_unref(&tfile); 386 } 387 EXPORT_SYMBOL(ttm_object_file_release); 388 389 struct ttm_object_file *ttm_object_file_init(struct ttm_object_device *tdev, 390 unsigned int hash_order) 391 { 392 struct ttm_object_file *tfile; 393 unsigned int i; 394 unsigned int j = 0; 395 int ret; 396 397 tfile = kmalloc(sizeof(*tfile), M_DRM, M_WAITOK); 398 if (unlikely(tfile == NULL)) 399 return NULL; 400 401 lockinit(&tfile->lock, "ttmfo", 0, LK_CANRECURSE); 402 tfile->tdev = tdev; 403 kref_init(&tfile->refcount); 404 INIT_LIST_HEAD(&tfile->ref_list); 405 406 for (i = 0; i < TTM_REF_NUM; ++i) { 407 ret = drm_ht_create(&tfile->ref_hash[i], hash_order); 408 if (ret) { 409 j = i; 410 goto out_err; 411 } 412 } 413 414 return tfile; 415 out_err: 416 for (i = 0; i < j; ++i) 417 drm_ht_remove(&tfile->ref_hash[i]); 418 419 kfree(tfile); 420 421 return NULL; 422 } 423 EXPORT_SYMBOL(ttm_object_file_init); 424 425 struct ttm_object_device *ttm_object_device_init(struct ttm_mem_global 426 *mem_glob, 427 unsigned int hash_order) 428 { 429 struct ttm_object_device *tdev; 430 int ret; 431 432 tdev = kmalloc(sizeof(*tdev), M_DRM, M_WAITOK); 433 if (unlikely(tdev == NULL)) 434 return NULL; 435 436 tdev->mem_glob = mem_glob; 437 lockinit(&tdev->object_lock, "ttmdo", 0, LK_CANRECURSE); 438 atomic_set(&tdev->object_count, 0); 439 ret = drm_ht_create(&tdev->object_hash, hash_order); 440 441 if (likely(ret == 0)) 442 return tdev; 443 444 kfree(tdev); 445 return NULL; 446 } 447 EXPORT_SYMBOL(ttm_object_device_init); 448 449 void ttm_object_device_release(struct ttm_object_device **p_tdev) 450 { 451 struct ttm_object_device *tdev = *p_tdev; 452 453 *p_tdev = NULL; 454 455 lockmgr(&tdev->object_lock, LK_EXCLUSIVE); 456 drm_ht_remove(&tdev->object_hash); 457 lockmgr(&tdev->object_lock, LK_RELEASE); 458 459 kfree(tdev); 460 } 461 EXPORT_SYMBOL(ttm_object_device_release); 462