drivers/gpu/drm/ttm/ttm_object.c

   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/ttm/ttm_object.h>
  55 #include <drm/ttm/ttm_module.h>
  56 #include <linux/list.h>
  57 #include <linux/spinlock.h>
  58 #include <linux/slab.h>
  59 #include <linux/module.h>
  60 #include <linux/atomic.h>
  61
  62 struct ttm_object_file {
  63         struct ttm_object_device *tdev;
  64         rwlock_t lock;
  65         struct list_head ref_list;
  66         struct drm_open_hash ref_hash[TTM_REF_NUM];
  67         struct kref refcount;
  68 };
  69
  70 /**
  71  * struct ttm_object_device
  72  *
  73  * @object_lock: lock that protects the object_hash hash table.
  74  *
  75  * @object_hash: hash table for fast lookup of object global names.
  76  *
  77  * @object_count: Per device object count.
  78  *
  79  * This is the per-device data structure needed for ttm object management.
  80  */
  81
  82 struct ttm_object_device {
  83         rwlock_t object_lock;
  84         struct drm_open_hash object_hash;
  85         atomic_t object_count;
  86         struct ttm_mem_global *mem_glob;
  87 };
  88
  89 /**
  90  * struct ttm_ref_object
  91  *
  92  * @hash: Hash entry for the per-file object reference hash.
  93  *
  94  * @head: List entry for the per-file list of ref-objects.
  95  *
  96  * @kref: Ref count.
  97  *
  98  * @obj: Base object this ref object is referencing.
  99  *
 100  * @ref_type: Type of ref object.
 101  *
 102  * This is similar to an idr object, but it also has a hash table entry
 103  * that allows lookup with a pointer to the referenced object as a key. In
 104  * that way, one can easily detect whether a base object is referenced by
 105  * a particular ttm_object_file. It also carries a ref count to avoid creating
 106  * multiple ref objects if a ttm_object_file references the same base
 107  * object more than once.
 108  */
 109
 110 struct ttm_ref_object {
 111         struct drm_hash_item hash;
 112         struct list_head head;
 113         struct kref kref;
 114         enum ttm_ref_type ref_type;
 115         struct ttm_base_object *obj;
 116         struct ttm_object_file *tfile;
 117 };
 118
 119 static inline struct ttm_object_file *
 120 ttm_object_file_ref(struct ttm_object_file *tfile)
 121 {
 122         kref_get(&tfile->refcount);
 123         return tfile;
 124 }
 125
 126 static void ttm_object_file_destroy(struct kref *kref)
 127 {
 128         struct ttm_object_file *tfile =
 129                 container_of(kref, struct ttm_object_file, refcount);
 130
 131         kfree(tfile);
 132 }
 133
 134
 135 static inline void ttm_object_file_unref(struct ttm_object_file **p_tfile)
 136 {
 137         struct ttm_object_file *tfile = *p_tfile;
 138
 139         *p_tfile = NULL;
 140         kref_put(&tfile->refcount, ttm_object_file_destroy);
 141 }
 142
 143
 144 int ttm_base_object_init(struct ttm_object_file *tfile,
 145                          struct ttm_base_object *base,
 146                          bool shareable,
 147                          enum ttm_object_type object_type,
 148                          void (*refcount_release) (struct ttm_base_object **),
 149                          void (*ref_obj_release) (struct ttm_base_object *,
 150                                                   enum ttm_ref_type ref_type))
 151 {
 152         struct ttm_object_device *tdev = tfile->tdev;
 153         int ret;
 154
 155         base->shareable = shareable;
 156         base->tfile = ttm_object_file_ref(tfile);
 157         base->refcount_release = refcount_release;
 158         base->ref_obj_release = ref_obj_release;
 159         base->object_type = object_type;
 160         write_lock(&tdev->object_lock);
 161         kref_init(&base->refcount);
 162         ret = drm_ht_just_insert_please(&tdev->object_hash,
 163                                         &base->hash,
 164                                         (unsigned long)base, 31, 0, 0);
 165         write_unlock(&tdev->object_lock);
 166         if (unlikely(ret != 0))
 167                 goto out_err0;
 168
 169         ret = ttm_ref_object_add(tfile, base, TTM_REF_USAGE, NULL);
 170         if (unlikely(ret != 0))
 171                 goto out_err1;
 172
 173         ttm_base_object_unref(&base);
 174
 175         return 0;
 176 out_err1:
 177         (void)drm_ht_remove_item(&tdev->object_hash, &base->hash);
 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         (void)drm_ht_remove_item(&tdev->object_hash, &base->hash);
 190         write_unlock(&tdev->object_lock);
 191         if (base->refcount_release) {
 192                 ttm_object_file_unref(&base->tfile);
 193                 base->refcount_release(&base);
 194         }
 195         write_lock(&tdev->object_lock);
 196 }
 197
 198 void ttm_base_object_unref(struct ttm_base_object **p_base)
 199 {
 200         struct ttm_base_object *base = *p_base;
 201         struct ttm_object_device *tdev = base->tfile->tdev;
 202
 203         *p_base = NULL;
 204
 205         /*
 206          * Need to take the lock here to avoid racing with
 207          * users trying to look up the object.
 208          */
 209
 210         write_lock(&tdev->object_lock);
 211         kref_put(&base->refcount, ttm_release_base);
 212         write_unlock(&tdev->object_lock);
 213 }
 214 EXPORT_SYMBOL(ttm_base_object_unref);
 215
 216 struct ttm_base_object *ttm_base_object_lookup(struct ttm_object_file *tfile,
 217                                                uint32_t key)
 218 {
 219         struct ttm_object_device *tdev = tfile->tdev;
 220         struct ttm_base_object *base;
 221         struct drm_hash_item *hash;
 222         int ret;
 223
 224         read_lock(&tdev->object_lock);
 225         ret = drm_ht_find_item(&tdev->object_hash, key, &hash);
 226
 227         if (likely(ret == 0)) {
 228                 base = drm_hash_entry(hash, struct ttm_base_object, hash);
 229                 kref_get(&base->refcount);
 230         }
 231         read_unlock(&tdev->object_lock);
 232
 233         if (unlikely(ret != 0))
 234                 return NULL;
 235
 236         if (tfile != base->tfile && !base->shareable) {
 237                 pr_err("Attempted access of non-shareable object\n");
 238                 ttm_base_object_unref(&base);
 239                 return NULL;
 240         }
 241
 242         return base;
 243 }
 244 EXPORT_SYMBOL(ttm_base_object_lookup);
 245
 246 int ttm_ref_object_add(struct ttm_object_file *tfile,
 247                        struct ttm_base_object *base,
 248                        enum ttm_ref_type ref_type, bool *existed)
 249 {
 250         struct drm_open_hash *ht = &tfile->ref_hash[ref_type];
 251         struct ttm_ref_object *ref;
 252         struct drm_hash_item *hash;
 253         struct ttm_mem_global *mem_glob = tfile->tdev->mem_glob;
 254         int ret = -EINVAL;
 255
 256         if (existed != NULL)
 257                 *existed = true;
 258
 259         while (ret == -EINVAL) {
 260                 read_lock(&tfile->lock);
 261                 ret = drm_ht_find_item(ht, base->hash.key, &hash);
 262
 263                 if (ret == 0) {
 264                         ref = drm_hash_entry(hash, struct ttm_ref_object, hash);
 265                         kref_get(&ref->kref);
 266                         read_unlock(&tfile->lock);
 267                         break;
 268                 }
 269
 270                 read_unlock(&tfile->lock);
 271                 ret = ttm_mem_global_alloc(mem_glob, sizeof(*ref),
 272                                            false, false);
 273                 if (unlikely(ret != 0))
 274                         return ret;
 275                 ref = kmalloc(sizeof(*ref), GFP_KERNEL);
 276                 if (unlikely(ref == NULL)) {
 277                         ttm_mem_global_free(mem_glob, sizeof(*ref));
 278                         return -ENOMEM;
 279                 }
 280
 281                 ref->hash.key = base->hash.key;
 282                 ref->obj = base;
 283                 ref->tfile = tfile;
 284                 ref->ref_type = ref_type;
 285                 kref_init(&ref->kref);
 286
 287                 write_lock(&tfile->lock);
 288                 ret = drm_ht_insert_item(ht, &ref->hash);
 289
 290                 if (likely(ret == 0)) {
 291                         list_add_tail(&ref->head, &tfile->ref_list);
 292                         kref_get(&base->refcount);
 293                         write_unlock(&tfile->lock);
 294                         if (existed != NULL)
 295                                 *existed = false;
 296                         break;
 297                 }
 298
 299                 write_unlock(&tfile->lock);
 300                 BUG_ON(ret != -EINVAL);
 301
 302                 ttm_mem_global_free(mem_glob, sizeof(*ref));
 303                 kfree(ref);
 304         }
 305
 306         return ret;
 307 }
 308 EXPORT_SYMBOL(ttm_ref_object_add);
 309
 310 static void ttm_ref_object_release(struct kref *kref)
 311 {
 312         struct ttm_ref_object *ref =
 313             container_of(kref, struct ttm_ref_object, kref);
 314         struct ttm_base_object *base = ref->obj;
 315         struct ttm_object_file *tfile = ref->tfile;
 316         struct drm_open_hash *ht;
 317         struct ttm_mem_global *mem_glob = tfile->tdev->mem_glob;
 318
 319         ht = &tfile->ref_hash[ref->ref_type];
 320         (void)drm_ht_remove_item(ht, &ref->hash);
 321         list_del(&ref->head);
 322         write_unlock(&tfile->lock);
 323
 324         if (ref->ref_type != TTM_REF_USAGE && base->ref_obj_release)
 325                 base->ref_obj_release(base, ref->ref_type);
 326
 327         ttm_base_object_unref(&ref->obj);
 328         ttm_mem_global_free(mem_glob, sizeof(*ref));
 329         kfree(ref);
 330         write_lock(&tfile->lock);
 331 }
 332
 333 int ttm_ref_object_base_unref(struct ttm_object_file *tfile,
 334                               unsigned long key, enum ttm_ref_type ref_type)
 335 {
 336         struct drm_open_hash *ht = &tfile->ref_hash[ref_type];
 337         struct ttm_ref_object *ref;
 338         struct drm_hash_item *hash;
 339         int ret;
 340
 341         write_lock(&tfile->lock);
 342         ret = drm_ht_find_item(ht, key, &hash);
 343         if (unlikely(ret != 0)) {
 344                 write_unlock(&tfile->lock);
 345                 return -EINVAL;
 346         }
 347         ref = drm_hash_entry(hash, struct ttm_ref_object, hash);
 348         kref_put(&ref->kref, ttm_ref_object_release);
 349         write_unlock(&tfile->lock);
 350         return 0;
 351 }
 352 EXPORT_SYMBOL(ttm_ref_object_base_unref);
 353
 354 void ttm_object_file_release(struct ttm_object_file **p_tfile)
 355 {
 356         struct ttm_ref_object *ref;
 357         struct list_head *list;
 358         unsigned int i;
 359         struct ttm_object_file *tfile = *p_tfile;
 360
 361         *p_tfile = NULL;
 362         write_lock(&tfile->lock);
 363
 364         /*
 365          * Since we release the lock within the loop, we have to
 366          * restart it from the beginning each time.
 367          */
 368
 369         while (!list_empty(&tfile->ref_list)) {
 370                 list = tfile->ref_list.next;
 371                 ref = list_entry(list, struct ttm_ref_object, head);
 372                 ttm_ref_object_release(&ref->kref);
 373         }
 374
 375         for (i = 0; i < TTM_REF_NUM; ++i)
 376                 drm_ht_remove(&tfile->ref_hash[i]);
 377
 378         write_unlock(&tfile->lock);
 379         ttm_object_file_unref(&tfile);
 380 }
 381 EXPORT_SYMBOL(ttm_object_file_release);
 382
 383 struct ttm_object_file *ttm_object_file_init(struct ttm_object_device *tdev,
 384                                              unsigned int hash_order)
 385 {
 386         struct ttm_object_file *tfile = kmalloc(sizeof(*tfile), GFP_KERNEL);
 387         unsigned int i;
 388         unsigned int j = 0;
 389         int ret;
 390
 391         if (unlikely(tfile == NULL))
 392                 return NULL;
 393
 394         rwlock_init(&tfile->lock);
 395         tfile->tdev = tdev;
 396         kref_init(&tfile->refcount);
 397         INIT_LIST_HEAD(&tfile->ref_list);
 398
 399         for (i = 0; i < TTM_REF_NUM; ++i) {
 400                 ret = drm_ht_create(&tfile->ref_hash[i], hash_order);
 401                 if (ret) {
 402                         j = i;
 403                         goto out_err;
 404                 }
 405         }
 406
 407         return tfile;
 408 out_err:
 409         for (i = 0; i < j; ++i)
 410                 drm_ht_remove(&tfile->ref_hash[i]);
 411
 412         kfree(tfile);
 413
 414         return NULL;
 415 }
 416 EXPORT_SYMBOL(ttm_object_file_init);
 417
 418 struct ttm_object_device *ttm_object_device_init(struct ttm_mem_global
 419                                                  *mem_glob,
 420                                                  unsigned int hash_order)
 421 {
 422         struct ttm_object_device *tdev = kmalloc(sizeof(*tdev), GFP_KERNEL);
 423         int ret;
 424
 425         if (unlikely(tdev == NULL))
 426                 return NULL;
 427
 428         tdev->mem_glob = mem_glob;
 429         rwlock_init(&tdev->object_lock);
 430         atomic_set(&tdev->object_count, 0);
 431         ret = drm_ht_create(&tdev->object_hash, hash_order);
 432
 433         if (likely(ret == 0))
 434                 return tdev;
 435
 436         kfree(tdev);
 437         return NULL;
 438 }
 439 EXPORT_SYMBOL(ttm_object_device_init);
 440
 441 void ttm_object_device_release(struct ttm_object_device **p_tdev)
 442 {
 443         struct ttm_object_device *tdev = *p_tdev;
 444
 445         *p_tdev = NULL;
 446
 447         write_lock(&tdev->object_lock);
 448         drm_ht_remove(&tdev->object_hash);
 449         write_unlock(&tdev->object_lock);
 450
 451         kfree(tdev);
 452 }
 453 EXPORT_SYMBOL(ttm_object_device_release);