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 drm_free(tfile, M_DRM); 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 kprintf("[TTM] Attempted access of non-shareable object %p\n", 244 base); 245 ttm_base_object_unref(&base); 246 return NULL; 247 } 248 249 return base; 250 } 251 EXPORT_SYMBOL(ttm_base_object_lookup); 252 253 int ttm_ref_object_add(struct ttm_object_file *tfile, 254 struct ttm_base_object *base, 255 enum ttm_ref_type ref_type, bool *existed) 256 { 257 struct drm_open_hash *ht = &tfile->ref_hash[ref_type]; 258 struct ttm_ref_object *ref; 259 struct drm_hash_item *hash; 260 struct ttm_mem_global *mem_glob = tfile->tdev->mem_glob; 261 int ret = -EINVAL; 262 263 if (existed != NULL) 264 *existed = true; 265 266 while (ret == -EINVAL) { 267 lockmgr(&tfile->lock, LK_EXCLUSIVE); 268 ret = drm_ht_find_item(ht, base->hash.key, &hash); 269 270 if (ret == 0) { 271 ref = drm_hash_entry(hash, struct ttm_ref_object, hash); 272 kref_get(&ref->kref); 273 lockmgr(&tfile->lock, LK_RELEASE); 274 break; 275 } 276 277 lockmgr(&tfile->lock, LK_RELEASE); 278 ret = ttm_mem_global_alloc(mem_glob, sizeof(*ref), 279 false, false); 280 if (unlikely(ret != 0)) 281 return ret; 282 ref = kmalloc(sizeof(*ref), M_DRM, M_WAITOK); 283 if (unlikely(ref == NULL)) { 284 ttm_mem_global_free(mem_glob, sizeof(*ref)); 285 return -ENOMEM; 286 } 287 288 ref->hash.key = base->hash.key; 289 ref->obj = base; 290 ref->tfile = tfile; 291 ref->ref_type = ref_type; 292 kref_init(&ref->kref); 293 294 lockmgr(&tfile->lock, LK_EXCLUSIVE); 295 ret = drm_ht_insert_item(ht, &ref->hash); 296 297 if (likely(ret == 0)) { 298 list_add_tail(&ref->head, &tfile->ref_list); 299 kref_get(&base->refcount); 300 lockmgr(&tfile->lock, LK_RELEASE); 301 if (existed != NULL) 302 *existed = false; 303 break; 304 } 305 306 lockmgr(&tfile->lock, LK_RELEASE); 307 BUG_ON(ret != -EINVAL); 308 309 ttm_mem_global_free(mem_glob, sizeof(*ref)); 310 drm_free(ref, M_DRM); 311 } 312 313 return ret; 314 } 315 EXPORT_SYMBOL(ttm_ref_object_add); 316 317 static void ttm_ref_object_release(struct kref *kref) 318 { 319 struct ttm_ref_object *ref = 320 container_of(kref, struct ttm_ref_object, kref); 321 struct ttm_base_object *base = ref->obj; 322 struct ttm_object_file *tfile = ref->tfile; 323 struct drm_open_hash *ht; 324 struct ttm_mem_global *mem_glob = tfile->tdev->mem_glob; 325 326 ht = &tfile->ref_hash[ref->ref_type]; 327 (void)drm_ht_remove_item(ht, &ref->hash); 328 list_del(&ref->head); 329 lockmgr(&tfile->lock, LK_RELEASE); 330 331 if (ref->ref_type != TTM_REF_USAGE && base->ref_obj_release) 332 base->ref_obj_release(base, ref->ref_type); 333 334 ttm_base_object_unref(&ref->obj); 335 ttm_mem_global_free(mem_glob, sizeof(*ref)); 336 drm_free(ref, M_DRM); 337 lockmgr(&tfile->lock, LK_EXCLUSIVE); 338 } 339 340 int ttm_ref_object_base_unref(struct ttm_object_file *tfile, 341 unsigned long key, enum ttm_ref_type ref_type) 342 { 343 struct drm_open_hash *ht = &tfile->ref_hash[ref_type]; 344 struct ttm_ref_object *ref; 345 struct drm_hash_item *hash; 346 int ret; 347 348 lockmgr(&tfile->lock, LK_EXCLUSIVE); 349 ret = drm_ht_find_item(ht, key, &hash); 350 if (unlikely(ret != 0)) { 351 lockmgr(&tfile->lock, LK_RELEASE); 352 return -EINVAL; 353 } 354 ref = drm_hash_entry(hash, struct ttm_ref_object, hash); 355 kref_put(&ref->kref, ttm_ref_object_release); 356 lockmgr(&tfile->lock, LK_RELEASE); 357 return 0; 358 } 359 EXPORT_SYMBOL(ttm_ref_object_base_unref); 360 361 void ttm_object_file_release(struct ttm_object_file **p_tfile) 362 { 363 struct ttm_ref_object *ref; 364 struct list_head *list; 365 unsigned int i; 366 struct ttm_object_file *tfile = *p_tfile; 367 368 *p_tfile = NULL; 369 lockmgr(&tfile->lock, LK_EXCLUSIVE); 370 371 /* 372 * Since we release the lock within the loop, we have to 373 * restart it from the beginning each time. 374 */ 375 376 while (!list_empty(&tfile->ref_list)) { 377 list = tfile->ref_list.next; 378 ref = list_entry(list, struct ttm_ref_object, head); 379 ttm_ref_object_release(&ref->kref); 380 } 381 382 for (i = 0; i < TTM_REF_NUM; ++i) 383 drm_ht_remove(&tfile->ref_hash[i]); 384 385 lockmgr(&tfile->lock, LK_RELEASE); 386 ttm_object_file_unref(&tfile); 387 } 388 EXPORT_SYMBOL(ttm_object_file_release); 389 390 struct ttm_object_file *ttm_object_file_init(struct ttm_object_device *tdev, 391 unsigned int hash_order) 392 { 393 struct ttm_object_file *tfile; 394 unsigned int i; 395 unsigned int j = 0; 396 int ret; 397 398 tfile = kmalloc(sizeof(*tfile), M_DRM, M_WAITOK); 399 if (unlikely(tfile == NULL)) 400 return NULL; 401 402 lockinit(&tfile->lock, "ttmfo", 0, LK_CANRECURSE); 403 tfile->tdev = tdev; 404 kref_init(&tfile->refcount); 405 INIT_LIST_HEAD(&tfile->ref_list); 406 407 for (i = 0; i < TTM_REF_NUM; ++i) { 408 ret = drm_ht_create(&tfile->ref_hash[i], hash_order); 409 if (ret) { 410 j = i; 411 goto out_err; 412 } 413 } 414 415 return tfile; 416 out_err: 417 for (i = 0; i < j; ++i) 418 drm_ht_remove(&tfile->ref_hash[i]); 419 420 drm_free(tfile, M_DRM); 421 422 return NULL; 423 } 424 EXPORT_SYMBOL(ttm_object_file_init); 425 426 struct ttm_object_device *ttm_object_device_init(struct ttm_mem_global 427 *mem_glob, 428 unsigned int hash_order) 429 { 430 struct ttm_object_device *tdev; 431 int ret; 432 433 tdev = kmalloc(sizeof(*tdev), M_DRM, M_WAITOK); 434 if (unlikely(tdev == NULL)) 435 return NULL; 436 437 tdev->mem_glob = mem_glob; 438 lockinit(&tdev->object_lock, "ttmdo", 0, LK_CANRECURSE); 439 atomic_set(&tdev->object_count, 0); 440 ret = drm_ht_create(&tdev->object_hash, hash_order); 441 442 if (likely(ret == 0)) 443 return tdev; 444 445 drm_free(tdev, M_DRM); 446 return NULL; 447 } 448 EXPORT_SYMBOL(ttm_object_device_init); 449 450 void ttm_object_device_release(struct ttm_object_device **p_tdev) 451 { 452 struct ttm_object_device *tdev = *p_tdev; 453 454 *p_tdev = NULL; 455 456 lockmgr(&tdev->object_lock, LK_EXCLUSIVE); 457 drm_ht_remove(&tdev->object_hash); 458 lockmgr(&tdev->object_lock, LK_RELEASE); 459 460 drm_free(tdev, M_DRM); 461 } 462 EXPORT_SYMBOL(ttm_object_device_release); 463