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         spinlock_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         kref_init(&base->refcount);
 161         spin_lock(&tdev->object_lock);
 162         ret = drm_ht_just_insert_please_rcu(&tdev->object_hash,
 163                                             &base->hash,
 164                                             (unsigned long)base, 31, 0, 0);
 165         spin_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         spin_lock(&tdev->object_lock);
 178         (void)drm_ht_remove_item_rcu(&tdev->object_hash, &base->hash);
 179         spin_unlock(&tdev->object_lock);
 180 out_err0:
 181         return ret;
 182 }
 183 EXPORT_SYMBOL(ttm_base_object_init);
 184
 185 static void ttm_release_base(struct kref *kref)
 186 {
 187         struct ttm_base_object *base =
 188             container_of(kref, struct ttm_base_object, refcount);
 189         struct ttm_object_device *tdev = base->tfile->tdev;
 190
 191         spin_lock(&tdev->object_lock);
 192         (void)drm_ht_remove_item_rcu(&tdev->object_hash, &base->hash);
 193         spin_unlock(&tdev->object_lock);
 194
 195         /*
 196          * Note: We don't use synchronize_rcu() here because it's far
 197          * too slow. It's up to the user to free the object using
 198          * call_rcu() or ttm_base_object_kfree().
 199          */
 200
 201         if (base->refcount_release) {
 202                 ttm_object_file_unref(&base->tfile);
 203                 base->refcount_release(&base);
 204         }
 205 }
 206
 207 void ttm_base_object_unref(struct ttm_base_object **p_base)
 208 {
 209         struct ttm_base_object *base = *p_base;
 210
 211         *p_base = NULL;
 212
 213         kref_put(&base->refcount, ttm_release_base);
 214 }
 215 EXPORT_SYMBOL(ttm_base_object_unref);
 216
 217 struct ttm_base_object *ttm_base_object_lookup(struct ttm_object_file *tfile,
 218                                                uint32_t key)
 219 {
 220         struct ttm_object_device *tdev = tfile->tdev;
 221         struct ttm_base_object *uninitialized_var(base);
 222         struct drm_hash_item *hash;
 223         int ret;
 224
 225         rcu_read_lock();
 226         ret = drm_ht_find_item_rcu(&tdev->object_hash, key, &hash);
 227
 228         if (likely(ret == 0)) {
 229                 base = drm_hash_entry(hash, struct ttm_base_object, hash);
 230                 ret = kref_get_unless_zero(&base->refcount) ? 0 : -EINVAL;
 231         }
 232         rcu_read_unlock();
 233
 234         if (unlikely(ret != 0))
 235                 return NULL;
 236
 237         if (tfile != base->tfile && !base->shareable) {
 238                 pr_err("Attempted access of non-shareable object\n");
 239                 ttm_base_object_unref(&base);
 240                 return NULL;
 241         }
 242
 243         return base;
 244 }
 245 EXPORT_SYMBOL(ttm_base_object_lookup);
 246
 247 int ttm_ref_object_add(struct ttm_object_file *tfile,
 248                        struct ttm_base_object *base,
 249                        enum ttm_ref_type ref_type, bool *existed)
 250 {
 251         struct drm_open_hash *ht = &tfile->ref_hash[ref_type];
 252         struct ttm_ref_object *ref;
 253         struct drm_hash_item *hash;
 254         struct ttm_mem_global *mem_glob = tfile->tdev->mem_glob;
 255         int ret = -EINVAL;
 256
 257         if (existed != NULL)
 258                 *existed = true;
 259
 260         while (ret == -EINVAL) {
 261                 read_lock(&tfile->lock);
 262                 ret = drm_ht_find_item(ht, base->hash.key, &hash);
 263
 264                 if (ret == 0) {
 265                         ref = drm_hash_entry(hash, struct ttm_ref_object, hash);
 266                         kref_get(&ref->kref);
 267                         read_unlock(&tfile->lock);
 268                         break;
 269                 }
 270
 271                 read_unlock(&tfile->lock);
 272                 ret = ttm_mem_global_alloc(mem_glob, sizeof(*ref),
 273                                            false, false);
 274                 if (unlikely(ret != 0))
 275                         return ret;
 276                 ref = kmalloc(sizeof(*ref), GFP_KERNEL);
 277                 if (unlikely(ref == NULL)) {
 278                         ttm_mem_global_free(mem_glob, sizeof(*ref));
 279                         return -ENOMEM;
 280                 }
 281
 282                 ref->hash.key = base->hash.key;
 283                 ref->obj = base;
 284                 ref->tfile = tfile;
 285                 ref->ref_type = ref_type;
 286                 kref_init(&ref->kref);
 287
 288                 write_lock(&tfile->lock);
 289                 ret = drm_ht_insert_item(ht, &ref->hash);
 290
 291                 if (likely(ret == 0)) {
 292                         list_add_tail(&ref->head, &tfile->ref_list);
 293                         kref_get(&base->refcount);
 294                         write_unlock(&tfile->lock);
 295                         if (existed != NULL)
 296                                 *existed = false;
 297                         break;
 298                 }
 299
 300                 write_unlock(&tfile->lock);
 301                 BUG_ON(ret != -EINVAL);
 302
 303                 ttm_mem_global_free(mem_glob, sizeof(*ref));
 304                 kfree(ref);
 305         }
 306
 307         return ret;
 308 }
 309 EXPORT_SYMBOL(ttm_ref_object_add);
 310
 311 static void ttm_ref_object_release(struct kref *kref)
 312 {
 313         struct ttm_ref_object *ref =
 314             container_of(kref, struct ttm_ref_object, kref);
 315         struct ttm_base_object *base = ref->obj;
 316         struct ttm_object_file *tfile = ref->tfile;
 317         struct drm_open_hash *ht;
 318         struct ttm_mem_global *mem_glob = tfile->tdev->mem_glob;
 319
 320         ht = &tfile->ref_hash[ref->ref_type];
 321         (void)drm_ht_remove_item(ht, &ref->hash);
 322         list_del(&ref->head);
 323         write_unlock(&tfile->lock);
 324
 325         if (ref->ref_type != TTM_REF_USAGE && base->ref_obj_release)
 326                 base->ref_obj_release(base, ref->ref_type);
 327
 328         ttm_base_object_unref(&ref->obj);
 329         ttm_mem_global_free(mem_glob, sizeof(*ref));
 330         kfree(ref);
 331         write_lock(&tfile->lock);
 332 }
 333
 334 int ttm_ref_object_base_unref(struct ttm_object_file *tfile,
 335                               unsigned long key, enum ttm_ref_type ref_type)
 336 {
 337         struct drm_open_hash *ht = &tfile->ref_hash[ref_type];
 338         struct ttm_ref_object *ref;
 339         struct drm_hash_item *hash;
 340         int ret;
 341
 342         write_lock(&tfile->lock);
 343         ret = drm_ht_find_item(ht, key, &hash);
 344         if (unlikely(ret != 0)) {
 345                 write_unlock(&tfile->lock);
 346                 return -EINVAL;
 347         }
 348         ref = drm_hash_entry(hash, struct ttm_ref_object, hash);
 349         kref_put(&ref->kref, ttm_ref_object_release);
 350         write_unlock(&tfile->lock);
 351         return 0;
 352 }
 353 EXPORT_SYMBOL(ttm_ref_object_base_unref);
 354
 355 void ttm_object_file_release(struct ttm_object_file **p_tfile)
 356 {
 357         struct ttm_ref_object *ref;
 358         struct list_head *list;
 359         unsigned int i;
 360         struct ttm_object_file *tfile = *p_tfile;
 361
 362         *p_tfile = NULL;
 363         write_lock(&tfile->lock);
 364
 365         /*
 366          * Since we release the lock within the loop, we have to
 367          * restart it from the beginning each time.
 368          */
 369
 370         while (!list_empty(&tfile->ref_list)) {
 371                 list = tfile->ref_list.next;
 372                 ref = list_entry(list, struct ttm_ref_object, head);
 373                 ttm_ref_object_release(&ref->kref);
 374         }
 375
 376         for (i = 0; i < TTM_REF_NUM; ++i)
 377                 drm_ht_remove(&tfile->ref_hash[i]);
 378
 379         write_unlock(&tfile->lock);
 380         ttm_object_file_unref(&tfile);
 381 }
 382 EXPORT_SYMBOL(ttm_object_file_release);
 383
 384 struct ttm_object_file *ttm_object_file_init(struct ttm_object_device *tdev,
 385                                              unsigned int hash_order)
 386 {
 387         struct ttm_object_file *tfile = kmalloc(sizeof(*tfile), GFP_KERNEL);
 388         unsigned int i;
 389         unsigned int j = 0;
 390         int ret;
 391
 392         if (unlikely(tfile == NULL))
 393                 return NULL;
 394
 395         rwlock_init(&tfile->lock);
 396         tfile->tdev = tdev;
 397         kref_init(&tfile->refcount);
 398         INIT_LIST_HEAD(&tfile->ref_list);
 399
 400         for (i = 0; i < TTM_REF_NUM; ++i) {
 401                 ret = drm_ht_create(&tfile->ref_hash[i], hash_order);
 402                 if (ret) {
 403                         j = i;
 404                         goto out_err;
 405                 }
 406         }
 407
 408         return tfile;
 409 out_err:
 410         for (i = 0; i < j; ++i)
 411                 drm_ht_remove(&tfile->ref_hash[i]);
 412
 413         kfree(tfile);
 414
 415         return NULL;
 416 }
 417 EXPORT_SYMBOL(ttm_object_file_init);
 418
 419 struct ttm_object_device *ttm_object_device_init(struct ttm_mem_global
 420                                                  *mem_glob,
 421                                                  unsigned int hash_order)
 422 {
 423         struct ttm_object_device *tdev = kmalloc(sizeof(*tdev), GFP_KERNEL);
 424         int ret;
 425
 426         if (unlikely(tdev == NULL))
 427                 return NULL;
 428
 429         tdev->mem_glob = mem_glob;
 430         spin_lock_init(&tdev->object_lock);
 431         atomic_set(&tdev->object_count, 0);
 432         ret = drm_ht_create(&tdev->object_hash, hash_order);
 433
 434         if (likely(ret == 0))
 435                 return tdev;
 436
 437         kfree(tdev);
 438         return NULL;
 439 }
 440 EXPORT_SYMBOL(ttm_object_device_init);
 441
 442 void ttm_object_device_release(struct ttm_object_device **p_tdev)
 443 {
 444         struct ttm_object_device *tdev = *p_tdev;
 445
 446         *p_tdev = NULL;
 447
 448         spin_lock(&tdev->object_lock);
 449         drm_ht_remove(&tdev->object_hash);
 450         spin_unlock(&tdev->object_lock);
 451
 452         kfree(tdev);
 453 }
 454 EXPORT_SYMBOL(ttm_object_device_release);