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 #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 <linux/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         enum ttm_ref_type ref_type;
 113         struct ttm_base_object *obj;
 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         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);