Thomas Hellstrom | 8807153 | 2009-12-06 21:46:24 +0100 | [diff] [blame^] | 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 | #include "ttm/ttm_object.h" |
| 53 | #include "ttm/ttm_module.h" |
| 54 | #include <linux/list.h> |
| 55 | #include <linux/spinlock.h> |
| 56 | #include <linux/slab.h> |
| 57 | #include <linux/module.h> |
| 58 | #include <asm/atomic.h> |
| 59 | |
| 60 | struct ttm_object_file { |
| 61 | struct ttm_object_device *tdev; |
| 62 | rwlock_t lock; |
| 63 | struct list_head ref_list; |
| 64 | struct drm_open_hash ref_hash[TTM_REF_NUM]; |
| 65 | struct kref refcount; |
| 66 | }; |
| 67 | |
| 68 | /** |
| 69 | * struct ttm_object_device |
| 70 | * |
| 71 | * @object_lock: lock that protects the object_hash hash table. |
| 72 | * |
| 73 | * @object_hash: hash table for fast lookup of object global names. |
| 74 | * |
| 75 | * @object_count: Per device object count. |
| 76 | * |
| 77 | * This is the per-device data structure needed for ttm object management. |
| 78 | */ |
| 79 | |
| 80 | struct ttm_object_device { |
| 81 | rwlock_t object_lock; |
| 82 | struct drm_open_hash object_hash; |
| 83 | atomic_t object_count; |
| 84 | struct ttm_mem_global *mem_glob; |
| 85 | }; |
| 86 | |
| 87 | /** |
| 88 | * struct ttm_ref_object |
| 89 | * |
| 90 | * @hash: Hash entry for the per-file object reference hash. |
| 91 | * |
| 92 | * @head: List entry for the per-file list of ref-objects. |
| 93 | * |
| 94 | * @kref: Ref count. |
| 95 | * |
| 96 | * @obj: Base object this ref object is referencing. |
| 97 | * |
| 98 | * @ref_type: Type of ref object. |
| 99 | * |
| 100 | * This is similar to an idr object, but it also has a hash table entry |
| 101 | * that allows lookup with a pointer to the referenced object as a key. In |
| 102 | * that way, one can easily detect whether a base object is referenced by |
| 103 | * a particular ttm_object_file. It also carries a ref count to avoid creating |
| 104 | * multiple ref objects if a ttm_object_file references the same base |
| 105 | * object more than once. |
| 106 | */ |
| 107 | |
| 108 | struct ttm_ref_object { |
| 109 | struct drm_hash_item hash; |
| 110 | struct list_head head; |
| 111 | struct kref kref; |
| 112 | struct ttm_base_object *obj; |
| 113 | enum ttm_ref_type ref_type; |
| 114 | struct ttm_object_file *tfile; |
| 115 | }; |
| 116 | |
| 117 | static inline struct ttm_object_file * |
| 118 | ttm_object_file_ref(struct ttm_object_file *tfile) |
| 119 | { |
| 120 | kref_get(&tfile->refcount); |
| 121 | return tfile; |
| 122 | } |
| 123 | |
| 124 | static void ttm_object_file_destroy(struct kref *kref) |
| 125 | { |
| 126 | struct ttm_object_file *tfile = |
| 127 | container_of(kref, struct ttm_object_file, refcount); |
| 128 | |
| 129 | kfree(tfile); |
| 130 | } |
| 131 | |
| 132 | |
| 133 | static inline void ttm_object_file_unref(struct ttm_object_file **p_tfile) |
| 134 | { |
| 135 | struct ttm_object_file *tfile = *p_tfile; |
| 136 | |
| 137 | *p_tfile = NULL; |
| 138 | kref_put(&tfile->refcount, ttm_object_file_destroy); |
| 139 | } |
| 140 | |
| 141 | |
| 142 | int ttm_base_object_init(struct ttm_object_file *tfile, |
| 143 | struct ttm_base_object *base, |
| 144 | bool shareable, |
| 145 | enum ttm_object_type object_type, |
| 146 | void (*refcount_release) (struct ttm_base_object **), |
| 147 | void (*ref_obj_release) (struct ttm_base_object *, |
| 148 | enum ttm_ref_type ref_type)) |
| 149 | { |
| 150 | struct ttm_object_device *tdev = tfile->tdev; |
| 151 | int ret; |
| 152 | |
| 153 | base->shareable = shareable; |
| 154 | base->tfile = ttm_object_file_ref(tfile); |
| 155 | base->refcount_release = refcount_release; |
| 156 | base->ref_obj_release = ref_obj_release; |
| 157 | base->object_type = object_type; |
| 158 | write_lock(&tdev->object_lock); |
| 159 | kref_init(&base->refcount); |
| 160 | ret = drm_ht_just_insert_please(&tdev->object_hash, |
| 161 | &base->hash, |
| 162 | (unsigned long)base, 31, 0, 0); |
| 163 | write_unlock(&tdev->object_lock); |
| 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 | (void)drm_ht_remove_item(&tdev->object_hash, &base->hash); |
| 176 | out_err0: |
| 177 | return ret; |
| 178 | } |
| 179 | EXPORT_SYMBOL(ttm_base_object_init); |
| 180 | |
| 181 | static void ttm_release_base(struct kref *kref) |
| 182 | { |
| 183 | struct ttm_base_object *base = |
| 184 | container_of(kref, struct ttm_base_object, refcount); |
| 185 | struct ttm_object_device *tdev = base->tfile->tdev; |
| 186 | |
| 187 | (void)drm_ht_remove_item(&tdev->object_hash, &base->hash); |
| 188 | write_unlock(&tdev->object_lock); |
| 189 | if (base->refcount_release) { |
| 190 | ttm_object_file_unref(&base->tfile); |
| 191 | base->refcount_release(&base); |
| 192 | } |
| 193 | write_lock(&tdev->object_lock); |
| 194 | } |
| 195 | |
| 196 | void ttm_base_object_unref(struct ttm_base_object **p_base) |
| 197 | { |
| 198 | struct ttm_base_object *base = *p_base; |
| 199 | struct ttm_object_device *tdev = base->tfile->tdev; |
| 200 | |
| 201 | *p_base = NULL; |
| 202 | |
| 203 | /* |
| 204 | * Need to take the lock here to avoid racing with |
| 205 | * users trying to look up the object. |
| 206 | */ |
| 207 | |
| 208 | write_lock(&tdev->object_lock); |
| 209 | (void)kref_put(&base->refcount, &ttm_release_base); |
| 210 | write_unlock(&tdev->object_lock); |
| 211 | } |
| 212 | EXPORT_SYMBOL(ttm_base_object_unref); |
| 213 | |
| 214 | struct ttm_base_object *ttm_base_object_lookup(struct ttm_object_file *tfile, |
| 215 | uint32_t key) |
| 216 | { |
| 217 | struct ttm_object_device *tdev = tfile->tdev; |
| 218 | struct ttm_base_object *base; |
| 219 | struct drm_hash_item *hash; |
| 220 | int ret; |
| 221 | |
| 222 | read_lock(&tdev->object_lock); |
| 223 | ret = drm_ht_find_item(&tdev->object_hash, key, &hash); |
| 224 | |
| 225 | if (likely(ret == 0)) { |
| 226 | base = drm_hash_entry(hash, struct ttm_base_object, hash); |
| 227 | kref_get(&base->refcount); |
| 228 | } |
| 229 | read_unlock(&tdev->object_lock); |
| 230 | |
| 231 | if (unlikely(ret != 0)) |
| 232 | return NULL; |
| 233 | |
| 234 | if (tfile != base->tfile && !base->shareable) { |
| 235 | printk(KERN_ERR TTM_PFX |
| 236 | "Attempted access of non-shareable object.\n"); |
| 237 | ttm_base_object_unref(&base); |
| 238 | return NULL; |
| 239 | } |
| 240 | |
| 241 | return base; |
| 242 | } |
| 243 | EXPORT_SYMBOL(ttm_base_object_lookup); |
| 244 | |
| 245 | int ttm_ref_object_add(struct ttm_object_file *tfile, |
| 246 | struct ttm_base_object *base, |
| 247 | enum ttm_ref_type ref_type, bool *existed) |
| 248 | { |
| 249 | struct drm_open_hash *ht = &tfile->ref_hash[ref_type]; |
| 250 | struct ttm_ref_object *ref; |
| 251 | struct drm_hash_item *hash; |
| 252 | struct ttm_mem_global *mem_glob = tfile->tdev->mem_glob; |
| 253 | int ret = -EINVAL; |
| 254 | |
| 255 | if (existed != NULL) |
| 256 | *existed = true; |
| 257 | |
| 258 | while (ret == -EINVAL) { |
| 259 | read_lock(&tfile->lock); |
| 260 | ret = drm_ht_find_item(ht, base->hash.key, &hash); |
| 261 | |
| 262 | if (ret == 0) { |
| 263 | ref = drm_hash_entry(hash, struct ttm_ref_object, hash); |
| 264 | kref_get(&ref->kref); |
| 265 | read_unlock(&tfile->lock); |
| 266 | break; |
| 267 | } |
| 268 | |
| 269 | read_unlock(&tfile->lock); |
| 270 | ret = ttm_mem_global_alloc(mem_glob, sizeof(*ref), |
| 271 | false, false); |
| 272 | if (unlikely(ret != 0)) |
| 273 | return ret; |
| 274 | ref = kmalloc(sizeof(*ref), GFP_KERNEL); |
| 275 | if (unlikely(ref == NULL)) { |
| 276 | ttm_mem_global_free(mem_glob, sizeof(*ref)); |
| 277 | return -ENOMEM; |
| 278 | } |
| 279 | |
| 280 | ref->hash.key = base->hash.key; |
| 281 | ref->obj = base; |
| 282 | ref->tfile = tfile; |
| 283 | ref->ref_type = ref_type; |
| 284 | kref_init(&ref->kref); |
| 285 | |
| 286 | write_lock(&tfile->lock); |
| 287 | ret = drm_ht_insert_item(ht, &ref->hash); |
| 288 | |
| 289 | if (likely(ret == 0)) { |
| 290 | list_add_tail(&ref->head, &tfile->ref_list); |
| 291 | kref_get(&base->refcount); |
| 292 | write_unlock(&tfile->lock); |
| 293 | if (existed != NULL) |
| 294 | *existed = false; |
| 295 | break; |
| 296 | } |
| 297 | |
| 298 | write_unlock(&tfile->lock); |
| 299 | BUG_ON(ret != -EINVAL); |
| 300 | |
| 301 | ttm_mem_global_free(mem_glob, sizeof(*ref)); |
| 302 | kfree(ref); |
| 303 | } |
| 304 | |
| 305 | return ret; |
| 306 | } |
| 307 | EXPORT_SYMBOL(ttm_ref_object_add); |
| 308 | |
| 309 | static void ttm_ref_object_release(struct kref *kref) |
| 310 | { |
| 311 | struct ttm_ref_object *ref = |
| 312 | container_of(kref, struct ttm_ref_object, kref); |
| 313 | struct ttm_base_object *base = ref->obj; |
| 314 | struct ttm_object_file *tfile = ref->tfile; |
| 315 | struct drm_open_hash *ht; |
| 316 | struct ttm_mem_global *mem_glob = tfile->tdev->mem_glob; |
| 317 | |
| 318 | ht = &tfile->ref_hash[ref->ref_type]; |
| 319 | (void)drm_ht_remove_item(ht, &ref->hash); |
| 320 | list_del(&ref->head); |
| 321 | write_unlock(&tfile->lock); |
| 322 | |
| 323 | if (ref->ref_type != TTM_REF_USAGE && base->ref_obj_release) |
| 324 | base->ref_obj_release(base, ref->ref_type); |
| 325 | |
| 326 | ttm_base_object_unref(&ref->obj); |
| 327 | ttm_mem_global_free(mem_glob, sizeof(*ref)); |
| 328 | kfree(ref); |
| 329 | write_lock(&tfile->lock); |
| 330 | } |
| 331 | |
| 332 | int ttm_ref_object_base_unref(struct ttm_object_file *tfile, |
| 333 | unsigned long key, enum ttm_ref_type ref_type) |
| 334 | { |
| 335 | struct drm_open_hash *ht = &tfile->ref_hash[ref_type]; |
| 336 | struct ttm_ref_object *ref; |
| 337 | struct drm_hash_item *hash; |
| 338 | int ret; |
| 339 | |
| 340 | write_lock(&tfile->lock); |
| 341 | ret = drm_ht_find_item(ht, key, &hash); |
| 342 | if (unlikely(ret != 0)) { |
| 343 | write_unlock(&tfile->lock); |
| 344 | return -EINVAL; |
| 345 | } |
| 346 | ref = drm_hash_entry(hash, struct ttm_ref_object, hash); |
| 347 | kref_put(&ref->kref, ttm_ref_object_release); |
| 348 | write_unlock(&tfile->lock); |
| 349 | return 0; |
| 350 | } |
| 351 | EXPORT_SYMBOL(ttm_ref_object_base_unref); |
| 352 | |
| 353 | void ttm_object_file_release(struct ttm_object_file **p_tfile) |
| 354 | { |
| 355 | struct ttm_ref_object *ref; |
| 356 | struct list_head *list; |
| 357 | unsigned int i; |
| 358 | struct ttm_object_file *tfile = *p_tfile; |
| 359 | |
| 360 | *p_tfile = NULL; |
| 361 | write_lock(&tfile->lock); |
| 362 | |
| 363 | /* |
| 364 | * Since we release the lock within the loop, we have to |
| 365 | * restart it from the beginning each time. |
| 366 | */ |
| 367 | |
| 368 | while (!list_empty(&tfile->ref_list)) { |
| 369 | list = tfile->ref_list.next; |
| 370 | ref = list_entry(list, struct ttm_ref_object, head); |
| 371 | ttm_ref_object_release(&ref->kref); |
| 372 | } |
| 373 | |
| 374 | for (i = 0; i < TTM_REF_NUM; ++i) |
| 375 | drm_ht_remove(&tfile->ref_hash[i]); |
| 376 | |
| 377 | write_unlock(&tfile->lock); |
| 378 | ttm_object_file_unref(&tfile); |
| 379 | } |
| 380 | EXPORT_SYMBOL(ttm_object_file_release); |
| 381 | |
| 382 | struct ttm_object_file *ttm_object_file_init(struct ttm_object_device *tdev, |
| 383 | unsigned int hash_order) |
| 384 | { |
| 385 | struct ttm_object_file *tfile = kmalloc(sizeof(*tfile), GFP_KERNEL); |
| 386 | unsigned int i; |
| 387 | unsigned int j = 0; |
| 388 | int ret; |
| 389 | |
| 390 | if (unlikely(tfile == NULL)) |
| 391 | return NULL; |
| 392 | |
| 393 | rwlock_init(&tfile->lock); |
| 394 | tfile->tdev = tdev; |
| 395 | kref_init(&tfile->refcount); |
| 396 | INIT_LIST_HEAD(&tfile->ref_list); |
| 397 | |
| 398 | for (i = 0; i < TTM_REF_NUM; ++i) { |
| 399 | ret = drm_ht_create(&tfile->ref_hash[i], hash_order); |
| 400 | if (ret) { |
| 401 | j = i; |
| 402 | goto out_err; |
| 403 | } |
| 404 | } |
| 405 | |
| 406 | return tfile; |
| 407 | out_err: |
| 408 | for (i = 0; i < j; ++i) |
| 409 | drm_ht_remove(&tfile->ref_hash[i]); |
| 410 | |
| 411 | kfree(tfile); |
| 412 | |
| 413 | return NULL; |
| 414 | } |
| 415 | EXPORT_SYMBOL(ttm_object_file_init); |
| 416 | |
| 417 | struct ttm_object_device *ttm_object_device_init(struct ttm_mem_global |
| 418 | *mem_glob, |
| 419 | unsigned int hash_order) |
| 420 | { |
| 421 | struct ttm_object_device *tdev = kmalloc(sizeof(*tdev), GFP_KERNEL); |
| 422 | int ret; |
| 423 | |
| 424 | if (unlikely(tdev == NULL)) |
| 425 | return NULL; |
| 426 | |
| 427 | tdev->mem_glob = mem_glob; |
| 428 | rwlock_init(&tdev->object_lock); |
| 429 | atomic_set(&tdev->object_count, 0); |
| 430 | ret = drm_ht_create(&tdev->object_hash, hash_order); |
| 431 | |
| 432 | if (likely(ret == 0)) |
| 433 | return tdev; |
| 434 | |
| 435 | kfree(tdev); |
| 436 | return NULL; |
| 437 | } |
| 438 | EXPORT_SYMBOL(ttm_object_device_init); |
| 439 | |
| 440 | void ttm_object_device_release(struct ttm_object_device **p_tdev) |
| 441 | { |
| 442 | struct ttm_object_device *tdev = *p_tdev; |
| 443 | |
| 444 | *p_tdev = NULL; |
| 445 | |
| 446 | write_lock(&tdev->object_lock); |
| 447 | drm_ht_remove(&tdev->object_hash); |
| 448 | write_unlock(&tdev->object_lock); |
| 449 | |
| 450 | kfree(tdev); |
| 451 | } |
| 452 | EXPORT_SYMBOL(ttm_object_device_release); |