drivers/dma-buf/sync_file.c

   1 /*
   2  * drivers/dma-buf/sync_file.c
   3  *
   4  * Copyright (C) 2012 Google, Inc.
   5  *
   6  * This software is licensed under the terms of the GNU General Public
   7  * License version 2, as published by the Free Software Foundation, and
   8  * may be copied, distributed, and modified under those terms.
   9  *
  10  * This program is distributed in the hope that it will be useful,
  11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13  * GNU General Public License for more details.
  14  *
  15  */
  16
  17 #include <linux/export.h>
  18 #include <linux/file.h>
  19 #include <linux/fs.h>
  20 #include <linux/kernel.h>
  21 #include <linux/poll.h>
  22 #include <linux/sched.h>
  23 #include <linux/slab.h>
  24 #include <linux/uaccess.h>
  25 #include <linux/anon_inodes.h>
  26 #include <linux/sync_file.h>
  27 #include <uapi/linux/sync_file.h>
  28
  29 static const struct file_operations sync_file_fops;
  30
  31 static struct sync_file *sync_file_alloc(void)
  32 {
  33         struct sync_file *sync_file;
  34
  35         sync_file = kzalloc(sizeof(*sync_file), GFP_KERNEL);
  36         if (!sync_file)
  37                 return NULL;
  38
  39         sync_file->file = anon_inode_getfile("sync_file", &sync_file_fops,
  40                                              sync_file, 0);
  41         if (IS_ERR(sync_file->file))
  42                 goto err;
  43
  44         kref_init(&sync_file->kref);
  45
  46         init_waitqueue_head(&sync_file->wq);
  47
  48         INIT_LIST_HEAD(&sync_file->cb.node);
  49
  50         return sync_file;
  51
  52 err:
  53         kfree(sync_file);
  54         return NULL;
  55 }
  56
  57 static void fence_check_cb_func(struct dma_fence *f, struct dma_fence_cb *cb)
  58 {
  59         struct sync_file *sync_file;
  60
  61         sync_file = container_of(cb, struct sync_file, cb);
  62
  63         wake_up_all(&sync_file->wq);
  64 }
  65
  66 /**
  67  * sync_file_create() - creates a sync file
  68  * @fence:      fence to add to the sync_fence
  69  *
  70  * Creates a sync_file containg @fence. This function acquires and additional
  71  * reference of @fence for the newly-created &sync_file, if it succeeds. The
  72  * sync_file can be released with fput(sync_file->file). Returns the
  73  * sync_file or NULL in case of error.
  74  */
  75 struct sync_file *sync_file_create(struct dma_fence *fence)
  76 {
  77         struct sync_file *sync_file;
  78
  79         sync_file = sync_file_alloc();
  80         if (!sync_file)
  81                 return NULL;
  82
  83         sync_file->fence = dma_fence_get(fence);
  84
  85         snprintf(sync_file->name, sizeof(sync_file->name), "%s-%s%llu-%d",
  86                  fence->ops->get_driver_name(fence),
  87                  fence->ops->get_timeline_name(fence), fence->context,
  88                  fence->seqno);
  89
  90         return sync_file;
  91 }
  92 EXPORT_SYMBOL(sync_file_create);
  93
  94 static struct sync_file *sync_file_fdget(int fd)
  95 {
  96         struct file *file = fget(fd);
  97
  98         if (!file)
  99                 return NULL;
 100
 101         if (file->f_op != &sync_file_fops)
 102                 goto err;
 103
 104         return file->private_data;
 105
 106 err:
 107         fput(file);
 108         return NULL;
 109 }
 110
 111 /**
 112  * sync_file_get_fence - get the fence related to the sync_file fd
 113  * @fd:         sync_file fd to get the fence from
 114  *
 115  * Ensures @fd references a valid sync_file and returns a fence that
 116  * represents all fence in the sync_file. On error NULL is returned.
 117  */
 118 struct dma_fence *sync_file_get_fence(int fd)
 119 {
 120         struct sync_file *sync_file;
 121         struct dma_fence *fence;
 122
 123         sync_file = sync_file_fdget(fd);
 124         if (!sync_file)
 125                 return NULL;
 126
 127         fence = dma_fence_get(sync_file->fence);
 128         fput(sync_file->file);
 129
 130         return fence;
 131 }
 132 EXPORT_SYMBOL(sync_file_get_fence);
 133
 134 static int sync_file_set_fence(struct sync_file *sync_file,
 135                                struct dma_fence **fences, int num_fences)
 136 {
 137         struct dma_fence_array *array;
 138
 139         /*
 140          * The reference for the fences in the new sync_file and held
 141          * in add_fence() during the merge procedure, so for num_fences == 1
 142          * we already own a new reference to the fence. For num_fence > 1
 143          * we own the reference of the dma_fence_array creation.
 144          */
 145         if (num_fences == 1) {
 146                 sync_file->fence = fences[0];
 147                 kfree(fences);
 148         } else {
 149                 array = dma_fence_array_create(num_fences, fences,
 150                                                dma_fence_context_alloc(1),
 151                                                1, false);
 152                 if (!array)
 153                         return -ENOMEM;
 154
 155                 sync_file->fence = &array->base;
 156         }
 157
 158         return 0;
 159 }
 160
 161 static struct dma_fence **get_fences(struct sync_file *sync_file,
 162                                      int *num_fences)
 163 {
 164         if (dma_fence_is_array(sync_file->fence)) {
 165                 struct dma_fence_array *array = to_dma_fence_array(sync_file->fence);
 166
 167                 *num_fences = array->num_fences;
 168                 return array->fences;
 169         }
 170
 171         *num_fences = 1;
 172         return &sync_file->fence;
 173 }
 174
 175 static void add_fence(struct dma_fence **fences,
 176                       int *i, struct dma_fence *fence)
 177 {
 178         fences[*i] = fence;
 179
 180         if (!dma_fence_is_signaled(fence)) {
 181                 dma_fence_get(fence);
 182                 (*i)++;
 183         }
 184 }
 185
 186 /**
 187  * sync_file_merge() - merge two sync_files
 188  * @name:       name of new fence
 189  * @a:          sync_file a
 190  * @b:          sync_file b
 191  *
 192  * Creates a new sync_file which contains copies of all the fences in both
 193  * @a and @b.  @a and @b remain valid, independent sync_file. Returns the
 194  * new merged sync_file or NULL in case of error.
 195  */
 196 static struct sync_file *sync_file_merge(const char *name, struct sync_file *a,
 197                                          struct sync_file *b)
 198 {
 199         struct sync_file *sync_file;
 200         struct dma_fence **fences, **nfences, **a_fences, **b_fences;
 201         int i, i_a, i_b, num_fences, a_num_fences, b_num_fences;
 202
 203         sync_file = sync_file_alloc();
 204         if (!sync_file)
 205                 return NULL;
 206
 207         a_fences = get_fences(a, &a_num_fences);
 208         b_fences = get_fences(b, &b_num_fences);
 209         if (a_num_fences > INT_MAX - b_num_fences)
 210                 return NULL;
 211
 212         num_fences = a_num_fences + b_num_fences;
 213
 214         fences = kcalloc(num_fences, sizeof(*fences), GFP_KERNEL);
 215         if (!fences)
 216                 goto err;
 217
 218         /*
 219          * Assume sync_file a and b are both ordered and have no
 220          * duplicates with the same context.
 221          *
 222          * If a sync_file can only be created with sync_file_merge
 223          * and sync_file_create, this is a reasonable assumption.
 224          */
 225         for (i = i_a = i_b = 0; i_a < a_num_fences && i_b < b_num_fences; ) {
 226                 struct dma_fence *pt_a = a_fences[i_a];
 227                 struct dma_fence *pt_b = b_fences[i_b];
 228
 229                 if (pt_a->context < pt_b->context) {
 230                         add_fence(fences, &i, pt_a);
 231
 232                         i_a++;
 233                 } else if (pt_a->context > pt_b->context) {
 234                         add_fence(fences, &i, pt_b);
 235
 236                         i_b++;
 237                 } else {
 238                         if (pt_a->seqno - pt_b->seqno <= INT_MAX)
 239                                 add_fence(fences, &i, pt_a);
 240                         else
 241                                 add_fence(fences, &i, pt_b);
 242
 243                         i_a++;
 244                         i_b++;
 245                 }
 246         }
 247
 248         for (; i_a < a_num_fences; i_a++)
 249                 add_fence(fences, &i, a_fences[i_a]);
 250
 251         for (; i_b < b_num_fences; i_b++)
 252                 add_fence(fences, &i, b_fences[i_b]);
 253
 254         if (i == 0)
 255                 fences[i++] = dma_fence_get(a_fences[0]);
 256
 257         if (num_fences > i) {
 258                 nfences = krealloc(fences, i * sizeof(*fences),
 259                                   GFP_KERNEL);
 260                 if (!nfences)
 261                         goto err;
 262
 263                 fences = nfences;
 264         }
 265
 266         if (sync_file_set_fence(sync_file, fences, i) < 0) {
 267                 kfree(fences);
 268                 goto err;
 269         }
 270
 271         strlcpy(sync_file->name, name, sizeof(sync_file->name));
 272         return sync_file;
 273
 274 err:
 275         fput(sync_file->file);
 276         return NULL;
 277
 278 }
 279
 280 static void sync_file_free(struct kref *kref)
 281 {
 282         struct sync_file *sync_file = container_of(kref, struct sync_file,
 283                                                      kref);
 284
 285         if (test_bit(POLL_ENABLED, &sync_file->fence->flags))
 286                 dma_fence_remove_callback(sync_file->fence, &sync_file->cb);
 287         dma_fence_put(sync_file->fence);
 288         kfree(sync_file);
 289 }
 290
 291 static int sync_file_release(struct inode *inode, struct file *file)
 292 {
 293         struct sync_file *sync_file = file->private_data;
 294
 295         kref_put(&sync_file->kref, sync_file_free);
 296         return 0;
 297 }
 298
 299 static unsigned int sync_file_poll(struct file *file, poll_table *wait)
 300 {
 301         struct sync_file *sync_file = file->private_data;
 302
 303         poll_wait(file, &sync_file->wq, wait);
 304
 305         if (!test_and_set_bit(POLL_ENABLED, &sync_file->fence->flags)) {
 306                 if (dma_fence_add_callback(sync_file->fence, &sync_file->cb,
 307                                            fence_check_cb_func) < 0)
 308                         wake_up_all(&sync_file->wq);
 309         }
 310
 311         return dma_fence_is_signaled(sync_file->fence) ? POLLIN : 0;
 312 }
 313
 314 static long sync_file_ioctl_merge(struct sync_file *sync_file,
 315                                   unsigned long arg)
 316 {
 317         int fd = get_unused_fd_flags(O_CLOEXEC);
 318         int err;
 319         struct sync_file *fence2, *fence3;
 320         struct sync_merge_data data;
 321
 322         if (fd < 0)
 323                 return fd;
 324
 325         if (copy_from_user(&data, (void __user *)arg, sizeof(data))) {
 326                 err = -EFAULT;
 327                 goto err_put_fd;
 328         }
 329
 330         if (data.flags || data.pad) {
 331                 err = -EINVAL;
 332                 goto err_put_fd;
 333         }
 334
 335         fence2 = sync_file_fdget(data.fd2);
 336         if (!fence2) {
 337                 err = -ENOENT;
 338                 goto err_put_fd;
 339         }
 340
 341         data.name[sizeof(data.name) - 1] = '\0';
 342         fence3 = sync_file_merge(data.name, sync_file, fence2);
 343         if (!fence3) {
 344                 err = -ENOMEM;
 345                 goto err_put_fence2;
 346         }
 347
 348         data.fence = fd;
 349         if (copy_to_user((void __user *)arg, &data, sizeof(data))) {
 350                 err = -EFAULT;
 351                 goto err_put_fence3;
 352         }
 353
 354         fd_install(fd, fence3->file);
 355         fput(fence2->file);
 356         return 0;
 357
 358 err_put_fence3:
 359         fput(fence3->file);
 360
 361 err_put_fence2:
 362         fput(fence2->file);
 363
 364 err_put_fd:
 365         put_unused_fd(fd);
 366         return err;
 367 }
 368
 369 static void sync_fill_fence_info(struct dma_fence *fence,
 370                                  struct sync_fence_info *info)
 371 {
 372         strlcpy(info->obj_name, fence->ops->get_timeline_name(fence),
 373                 sizeof(info->obj_name));
 374         strlcpy(info->driver_name, fence->ops->get_driver_name(fence),
 375                 sizeof(info->driver_name));
 376
 377         info->status = dma_fence_get_status(fence);
 378         info->timestamp_ns = ktime_to_ns(fence->timestamp);
 379 }
 380
 381 static long sync_file_ioctl_fence_info(struct sync_file *sync_file,
 382                                        unsigned long arg)
 383 {
 384         struct sync_file_info info;
 385         struct sync_fence_info *fence_info = NULL;
 386         struct dma_fence **fences;
 387         __u32 size;
 388         int num_fences, ret, i;
 389
 390         if (copy_from_user(&info, (void __user *)arg, sizeof(info)))
 391                 return -EFAULT;
 392
 393         if (info.flags || info.pad)
 394                 return -EINVAL;
 395
 396         fences = get_fences(sync_file, &num_fences);
 397
 398         /*
 399          * Passing num_fences = 0 means that userspace doesn't want to
 400          * retrieve any sync_fence_info. If num_fences = 0 we skip filling
 401          * sync_fence_info and return the actual number of fences on
 402          * info->num_fences.
 403          */
 404         if (!info.num_fences)
 405                 goto no_fences;
 406
 407         if (info.num_fences < num_fences)
 408                 return -EINVAL;
 409
 410         size = num_fences * sizeof(*fence_info);
 411         fence_info = kzalloc(size, GFP_KERNEL);
 412         if (!fence_info)
 413                 return -ENOMEM;
 414
 415         for (i = 0; i < num_fences; i++)
 416                 sync_fill_fence_info(fences[i], &fence_info[i]);
 417
 418         if (copy_to_user(u64_to_user_ptr(info.sync_fence_info), fence_info,
 419                          size)) {
 420                 ret = -EFAULT;
 421                 goto out;
 422         }
 423
 424 no_fences:
 425         strlcpy(info.name, sync_file->name, sizeof(info.name));
 426         info.status = dma_fence_is_signaled(sync_file->fence);
 427         info.num_fences = num_fences;
 428
 429         if (copy_to_user((void __user *)arg, &info, sizeof(info)))
 430                 ret = -EFAULT;
 431         else
 432                 ret = 0;
 433
 434 out:
 435         kfree(fence_info);
 436
 437         return ret;
 438 }
 439
 440 static long sync_file_ioctl(struct file *file, unsigned int cmd,
 441                             unsigned long arg)
 442 {
 443         struct sync_file *sync_file = file->private_data;
 444
 445         switch (cmd) {
 446         case SYNC_IOC_MERGE:
 447                 return sync_file_ioctl_merge(sync_file, arg);
 448
 449         case SYNC_IOC_FILE_INFO:
 450                 return sync_file_ioctl_fence_info(sync_file, arg);
 451
 452         default:
 453                 return -ENOTTY;
 454         }
 455 }
 456
 457 static const struct file_operations sync_file_fops = {
 458         .release = sync_file_release,
 459         .poll = sync_file_poll,
 460         .unlocked_ioctl = sync_file_ioctl,
 461         .compat_ioctl = sync_file_ioctl,
 462 };