io_uring/rsrc.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 #include <linux/kernel.h>
   3 #include <linux/errno.h>
   4 #include <linux/fs.h>
   5 #include <linux/file.h>
   6 #include <linux/mm.h>
   7 #include <linux/slab.h>
   8 #include <linux/nospec.h>
   9 #include <linux/hugetlb.h>
  10 #include <linux/compat.h>
  11 #include <linux/io_uring.h>
  12
  13 #include <uapi/linux/io_uring.h>
  14
  15 #include "io_uring.h"
  16 #include "alloc_cache.h"
  17 #include "openclose.h"
  18 #include "rsrc.h"
  19 #include "memmap.h"
  20 #include "register.h"
  21
  22 struct io_rsrc_update {
  23         struct file                     *file;
  24         u64                             arg;
  25         u32                             nr_args;
  26         u32                             offset;
  27 };
  28
  29 static void io_rsrc_buf_put(struct io_ring_ctx *ctx, struct io_rsrc_put *prsrc);
  30 static int io_sqe_buffer_register(struct io_ring_ctx *ctx, struct iovec *iov,
  31                                   struct io_mapped_ubuf **pimu,
  32                                   struct page **last_hpage);
  33
  34 /* only define max */
  35 #define IORING_MAX_FIXED_FILES  (1U << 20)
  36 #define IORING_MAX_REG_BUFFERS  (1U << 14)
  37
  38 static const struct io_mapped_ubuf dummy_ubuf = {
  39         /* set invalid range, so io_import_fixed() fails meeting it */
  40         .ubuf = -1UL,
  41         .len = UINT_MAX,
  42 };
  43
  44 int __io_account_mem(struct user_struct *user, unsigned long nr_pages)
  45 {
  46         unsigned long page_limit, cur_pages, new_pages;
  47
  48         if (!nr_pages)
  49                 return 0;
  50
  51         /* Don't allow more pages than we can safely lock */
  52         page_limit = rlimit(RLIMIT_MEMLOCK) >> PAGE_SHIFT;
  53
  54         cur_pages = atomic_long_read(&user->locked_vm);
  55         do {
  56                 new_pages = cur_pages + nr_pages;
  57                 if (new_pages > page_limit)
  58                         return -ENOMEM;
  59         } while (!atomic_long_try_cmpxchg(&user->locked_vm,
  60                                           &cur_pages, new_pages));
  61         return 0;
  62 }
  63
  64 static void io_unaccount_mem(struct io_ring_ctx *ctx, unsigned long nr_pages)
  65 {
  66         if (ctx->user)
  67                 __io_unaccount_mem(ctx->user, nr_pages);
  68
  69         if (ctx->mm_account)
  70                 atomic64_sub(nr_pages, &ctx->mm_account->pinned_vm);
  71 }
  72
  73 static int io_account_mem(struct io_ring_ctx *ctx, unsigned long nr_pages)
  74 {
  75         int ret;
  76
  77         if (ctx->user) {
  78                 ret = __io_account_mem(ctx->user, nr_pages);
  79                 if (ret)
  80                         return ret;
  81         }
  82
  83         if (ctx->mm_account)
  84                 atomic64_add(nr_pages, &ctx->mm_account->pinned_vm);
  85
  86         return 0;
  87 }
  88
  89 static int io_buffer_validate(struct iovec *iov)
  90 {
  91         unsigned long tmp, acct_len = iov->iov_len + (PAGE_SIZE - 1);
  92
  93         /*
  94          * Don't impose further limits on the size and buffer
  95          * constraints here, we'll -EINVAL later when IO is
  96          * submitted if they are wrong.
  97          */
  98         if (!iov->iov_base)
  99                 return iov->iov_len ? -EFAULT : 0;
 100         if (!iov->iov_len)
 101                 return -EFAULT;
 102
 103         /* arbitrary limit, but we need something */
 104         if (iov->iov_len > SZ_1G)
 105                 return -EFAULT;
 106
 107         if (check_add_overflow((unsigned long)iov->iov_base, acct_len, &tmp))
 108                 return -EOVERFLOW;
 109
 110         return 0;
 111 }
 112
 113 static void io_buffer_unmap(struct io_ring_ctx *ctx, struct io_mapped_ubuf **slot)
 114 {
 115         struct io_mapped_ubuf *imu = *slot;
 116         unsigned int i;
 117
 118         *slot = NULL;
 119         if (imu != &dummy_ubuf) {
 120                 if (!refcount_dec_and_test(&imu->refs))
 121                         return;
 122                 for (i = 0; i < imu->nr_bvecs; i++)
 123                         unpin_user_page(imu->bvec[i].bv_page);
 124                 if (imu->acct_pages)
 125                         io_unaccount_mem(ctx, imu->acct_pages);
 126                 kvfree(imu);
 127         }
 128 }
 129
 130 static void io_rsrc_put_work(struct io_rsrc_node *node)
 131 {
 132         struct io_rsrc_put *prsrc = &node->item;
 133
 134         if (prsrc->tag)
 135                 io_post_aux_cqe(node->ctx, prsrc->tag, 0, 0);
 136
 137         switch (node->type) {
 138         case IORING_RSRC_FILE:
 139                 fput(prsrc->file);
 140                 break;
 141         case IORING_RSRC_BUFFER:
 142                 io_rsrc_buf_put(node->ctx, prsrc);
 143                 break;
 144         default:
 145                 WARN_ON_ONCE(1);
 146                 break;
 147         }
 148 }
 149
 150 void io_rsrc_node_destroy(struct io_ring_ctx *ctx, struct io_rsrc_node *node)
 151 {
 152         if (!io_alloc_cache_put(&ctx->rsrc_node_cache, node))
 153                 kfree(node);
 154 }
 155
 156 void io_rsrc_node_ref_zero(struct io_rsrc_node *node)
 157         __must_hold(&node->ctx->uring_lock)
 158 {
 159         struct io_ring_ctx *ctx = node->ctx;
 160
 161         while (!list_empty(&ctx->rsrc_ref_list)) {
 162                 node = list_first_entry(&ctx->rsrc_ref_list,
 163                                             struct io_rsrc_node, node);
 164                 /* recycle ref nodes in order */
 165                 if (node->refs)
 166                         break;
 167                 list_del(&node->node);
 168
 169                 if (likely(!node->empty))
 170                         io_rsrc_put_work(node);
 171                 io_rsrc_node_destroy(ctx, node);
 172         }
 173         if (list_empty(&ctx->rsrc_ref_list) && unlikely(ctx->rsrc_quiesce))
 174                 wake_up_all(&ctx->rsrc_quiesce_wq);
 175 }
 176
 177 struct io_rsrc_node *io_rsrc_node_alloc(struct io_ring_ctx *ctx)
 178 {
 179         struct io_rsrc_node *ref_node;
 180
 181         ref_node = io_alloc_cache_get(&ctx->rsrc_node_cache);
 182         if (!ref_node) {
 183                 ref_node = kzalloc(sizeof(*ref_node), GFP_KERNEL);
 184                 if (!ref_node)
 185                         return NULL;
 186         }
 187
 188         ref_node->ctx = ctx;
 189         ref_node->empty = 0;
 190         ref_node->refs = 1;
 191         return ref_node;
 192 }
 193
 194 __cold static int io_rsrc_ref_quiesce(struct io_rsrc_data *data,
 195                                       struct io_ring_ctx *ctx)
 196 {
 197         struct io_rsrc_node *backup;
 198         DEFINE_WAIT(we);
 199         int ret;
 200
 201         /* As We may drop ->uring_lock, other task may have started quiesce */
 202         if (data->quiesce)
 203                 return -ENXIO;
 204
 205         backup = io_rsrc_node_alloc(ctx);
 206         if (!backup)
 207                 return -ENOMEM;
 208         ctx->rsrc_node->empty = true;
 209         ctx->rsrc_node->type = -1;
 210         list_add_tail(&ctx->rsrc_node->node, &ctx->rsrc_ref_list);
 211         io_put_rsrc_node(ctx, ctx->rsrc_node);
 212         ctx->rsrc_node = backup;
 213
 214         if (list_empty(&ctx->rsrc_ref_list))
 215                 return 0;
 216
 217         if (ctx->flags & IORING_SETUP_DEFER_TASKRUN) {
 218                 atomic_set(&ctx->cq_wait_nr, 1);
 219                 smp_mb();
 220         }
 221
 222         ctx->rsrc_quiesce++;
 223         data->quiesce = true;
 224         do {
 225                 prepare_to_wait(&ctx->rsrc_quiesce_wq, &we, TASK_INTERRUPTIBLE);
 226                 mutex_unlock(&ctx->uring_lock);
 227
 228                 ret = io_run_task_work_sig(ctx);
 229                 if (ret < 0) {
 230                         finish_wait(&ctx->rsrc_quiesce_wq, &we);
 231                         mutex_lock(&ctx->uring_lock);
 232                         if (list_empty(&ctx->rsrc_ref_list))
 233                                 ret = 0;
 234                         break;
 235                 }
 236
 237                 schedule();
 238                 mutex_lock(&ctx->uring_lock);
 239                 ret = 0;
 240         } while (!list_empty(&ctx->rsrc_ref_list));
 241
 242         finish_wait(&ctx->rsrc_quiesce_wq, &we);
 243         data->quiesce = false;
 244         ctx->rsrc_quiesce--;
 245
 246         if (ctx->flags & IORING_SETUP_DEFER_TASKRUN) {
 247                 atomic_set(&ctx->cq_wait_nr, 0);
 248                 smp_mb();
 249         }
 250         return ret;
 251 }
 252
 253 static void io_free_page_table(void **table, size_t size)
 254 {
 255         unsigned i, nr_tables = DIV_ROUND_UP(size, PAGE_SIZE);
 256
 257         for (i = 0; i < nr_tables; i++)
 258                 kfree(table[i]);
 259         kfree(table);
 260 }
 261
 262 static void io_rsrc_data_free(struct io_rsrc_data *data)
 263 {
 264         size_t size = data->nr * sizeof(data->tags[0][0]);
 265
 266         if (data->tags)
 267                 io_free_page_table((void **)data->tags, size);
 268         kfree(data);
 269 }
 270
 271 static __cold void **io_alloc_page_table(size_t size)
 272 {
 273         unsigned i, nr_tables = DIV_ROUND_UP(size, PAGE_SIZE);
 274         size_t init_size = size;
 275         void **table;
 276
 277         table = kcalloc(nr_tables, sizeof(*table), GFP_KERNEL_ACCOUNT);
 278         if (!table)
 279                 return NULL;
 280
 281         for (i = 0; i < nr_tables; i++) {
 282                 unsigned int this_size = min_t(size_t, size, PAGE_SIZE);
 283
 284                 table[i] = kzalloc(this_size, GFP_KERNEL_ACCOUNT);
 285                 if (!table[i]) {
 286                         io_free_page_table(table, init_size);
 287                         return NULL;
 288                 }
 289                 size -= this_size;
 290         }
 291         return table;
 292 }
 293
 294 __cold static int io_rsrc_data_alloc(struct io_ring_ctx *ctx, int type,
 295                                      u64 __user *utags,
 296                                      unsigned nr, struct io_rsrc_data **pdata)
 297 {
 298         struct io_rsrc_data *data;
 299         int ret = 0;
 300         unsigned i;
 301
 302         data = kzalloc(sizeof(*data), GFP_KERNEL);
 303         if (!data)
 304                 return -ENOMEM;
 305         data->tags = (u64 **)io_alloc_page_table(nr * sizeof(data->tags[0][0]));
 306         if (!data->tags) {
 307                 kfree(data);
 308                 return -ENOMEM;
 309         }
 310
 311         data->nr = nr;
 312         data->ctx = ctx;
 313         data->rsrc_type = type;
 314         if (utags) {
 315                 ret = -EFAULT;
 316                 for (i = 0; i < nr; i++) {
 317                         u64 *tag_slot = io_get_tag_slot(data, i);
 318
 319                         if (copy_from_user(tag_slot, &utags[i],
 320                                            sizeof(*tag_slot)))
 321                                 goto fail;
 322                 }
 323         }
 324         *pdata = data;
 325         return 0;
 326 fail:
 327         io_rsrc_data_free(data);
 328         return ret;
 329 }
 330
 331 static int __io_sqe_files_update(struct io_ring_ctx *ctx,
 332                                  struct io_uring_rsrc_update2 *up,
 333                                  unsigned nr_args)
 334 {
 335         u64 __user *tags = u64_to_user_ptr(up->tags);
 336         __s32 __user *fds = u64_to_user_ptr(up->data);
 337         struct io_rsrc_data *data = ctx->file_data;
 338         struct io_fixed_file *file_slot;
 339         int fd, i, err = 0;
 340         unsigned int done;
 341
 342         if (!ctx->file_data)
 343                 return -ENXIO;
 344         if (up->offset + nr_args > ctx->nr_user_files)
 345                 return -EINVAL;
 346
 347         for (done = 0; done < nr_args; done++) {
 348                 u64 tag = 0;
 349
 350                 if ((tags && copy_from_user(&tag, &tags[done], sizeof(tag))) ||
 351                     copy_from_user(&fd, &fds[done], sizeof(fd))) {
 352                         err = -EFAULT;
 353                         break;
 354                 }
 355                 if ((fd == IORING_REGISTER_FILES_SKIP || fd == -1) && tag) {
 356                         err = -EINVAL;
 357                         break;
 358                 }
 359                 if (fd == IORING_REGISTER_FILES_SKIP)
 360                         continue;
 361
 362                 i = array_index_nospec(up->offset + done, ctx->nr_user_files);
 363                 file_slot = io_fixed_file_slot(&ctx->file_table, i);
 364
 365                 if (file_slot->file_ptr) {
 366                         err = io_queue_rsrc_removal(data, i,
 367                                                     io_slot_file(file_slot));
 368                         if (err)
 369                                 break;
 370                         file_slot->file_ptr = 0;
 371                         io_file_bitmap_clear(&ctx->file_table, i);
 372                 }
 373                 if (fd != -1) {
 374                         struct file *file = fget(fd);
 375
 376                         if (!file) {
 377                                 err = -EBADF;
 378                                 break;
 379                         }
 380                         /*
 381                          * Don't allow io_uring instances to be registered.
 382                          */
 383                         if (io_is_uring_fops(file)) {
 384                                 fput(file);
 385                                 err = -EBADF;
 386                                 break;
 387                         }
 388                         *io_get_tag_slot(data, i) = tag;
 389                         io_fixed_file_set(file_slot, file);
 390                         io_file_bitmap_set(&ctx->file_table, i);
 391                 }
 392         }
 393         return done ? done : err;
 394 }
 395
 396 static int __io_sqe_buffers_update(struct io_ring_ctx *ctx,
 397                                    struct io_uring_rsrc_update2 *up,
 398                                    unsigned int nr_args)
 399 {
 400         u64 __user *tags = u64_to_user_ptr(up->tags);
 401         struct iovec fast_iov, *iov;
 402         struct page *last_hpage = NULL;
 403         struct iovec __user *uvec;
 404         u64 user_data = up->data;
 405         __u32 done;
 406         int i, err;
 407
 408         if (!ctx->buf_data)
 409                 return -ENXIO;
 410         if (up->offset + nr_args > ctx->nr_user_bufs)
 411                 return -EINVAL;
 412
 413         for (done = 0; done < nr_args; done++) {
 414                 struct io_mapped_ubuf *imu;
 415                 u64 tag = 0;
 416
 417                 uvec = u64_to_user_ptr(user_data);
 418                 iov = iovec_from_user(uvec, 1, 1, &fast_iov, ctx->compat);
 419                 if (IS_ERR(iov)) {
 420                         err = PTR_ERR(iov);
 421                         break;
 422                 }
 423                 if (tags && copy_from_user(&tag, &tags[done], sizeof(tag))) {
 424                         err = -EFAULT;
 425                         break;
 426                 }
 427                 err = io_buffer_validate(iov);
 428                 if (err)
 429                         break;
 430                 if (!iov->iov_base && tag) {
 431                         err = -EINVAL;
 432                         break;
 433                 }
 434                 err = io_sqe_buffer_register(ctx, iov, &imu, &last_hpage);
 435                 if (err)
 436                         break;
 437
 438                 i = array_index_nospec(up->offset + done, ctx->nr_user_bufs);
 439                 if (ctx->user_bufs[i] != &dummy_ubuf) {
 440                         err = io_queue_rsrc_removal(ctx->buf_data, i,
 441                                                     ctx->user_bufs[i]);
 442                         if (unlikely(err)) {
 443                                 io_buffer_unmap(ctx, &imu);
 444                                 break;
 445                         }
 446                         ctx->user_bufs[i] = (struct io_mapped_ubuf *)&dummy_ubuf;
 447                 }
 448
 449                 ctx->user_bufs[i] = imu;
 450                 *io_get_tag_slot(ctx->buf_data, i) = tag;
 451                 if (ctx->compat)
 452                         user_data += sizeof(struct compat_iovec);
 453                 else
 454                         user_data += sizeof(struct iovec);
 455         }
 456         return done ? done : err;
 457 }
 458
 459 static int __io_register_rsrc_update(struct io_ring_ctx *ctx, unsigned type,
 460                                      struct io_uring_rsrc_update2 *up,
 461                                      unsigned nr_args)
 462 {
 463         __u32 tmp;
 464
 465         lockdep_assert_held(&ctx->uring_lock);
 466
 467         if (check_add_overflow(up->offset, nr_args, &tmp))
 468                 return -EOVERFLOW;
 469
 470         switch (type) {
 471         case IORING_RSRC_FILE:
 472                 return __io_sqe_files_update(ctx, up, nr_args);
 473         case IORING_RSRC_BUFFER:
 474                 return __io_sqe_buffers_update(ctx, up, nr_args);
 475         }
 476         return -EINVAL;
 477 }
 478
 479 int io_register_files_update(struct io_ring_ctx *ctx, void __user *arg,
 480                              unsigned nr_args)
 481 {
 482         struct io_uring_rsrc_update2 up;
 483
 484         if (!nr_args)
 485                 return -EINVAL;
 486         memset(&up, 0, sizeof(up));
 487         if (copy_from_user(&up, arg, sizeof(struct io_uring_rsrc_update)))
 488                 return -EFAULT;
 489         if (up.resv || up.resv2)
 490                 return -EINVAL;
 491         return __io_register_rsrc_update(ctx, IORING_RSRC_FILE, &up, nr_args);
 492 }
 493
 494 int io_register_rsrc_update(struct io_ring_ctx *ctx, void __user *arg,
 495                             unsigned size, unsigned type)
 496 {
 497         struct io_uring_rsrc_update2 up;
 498
 499         if (size != sizeof(up))
 500                 return -EINVAL;
 501         if (copy_from_user(&up, arg, sizeof(up)))
 502                 return -EFAULT;
 503         if (!up.nr || up.resv || up.resv2)
 504                 return -EINVAL;
 505         return __io_register_rsrc_update(ctx, type, &up, up.nr);
 506 }
 507
 508 __cold int io_register_rsrc(struct io_ring_ctx *ctx, void __user *arg,
 509                             unsigned int size, unsigned int type)
 510 {
 511         struct io_uring_rsrc_register rr;
 512
 513         /* keep it extendible */
 514         if (size != sizeof(rr))
 515                 return -EINVAL;
 516
 517         memset(&rr, 0, sizeof(rr));
 518         if (copy_from_user(&rr, arg, size))
 519                 return -EFAULT;
 520         if (!rr.nr || rr.resv2)
 521                 return -EINVAL;
 522         if (rr.flags & ~IORING_RSRC_REGISTER_SPARSE)
 523                 return -EINVAL;
 524
 525         switch (type) {
 526         case IORING_RSRC_FILE:
 527                 if (rr.flags & IORING_RSRC_REGISTER_SPARSE && rr.data)
 528                         break;
 529                 return io_sqe_files_register(ctx, u64_to_user_ptr(rr.data),
 530                                              rr.nr, u64_to_user_ptr(rr.tags));
 531         case IORING_RSRC_BUFFER:
 532                 if (rr.flags & IORING_RSRC_REGISTER_SPARSE && rr.data)
 533                         break;
 534                 return io_sqe_buffers_register(ctx, u64_to_user_ptr(rr.data),
 535                                                rr.nr, u64_to_user_ptr(rr.tags));
 536         }
 537         return -EINVAL;
 538 }
 539
 540 int io_files_update_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
 541 {
 542         struct io_rsrc_update *up = io_kiocb_to_cmd(req, struct io_rsrc_update);
 543
 544         if (unlikely(req->flags & (REQ_F_FIXED_FILE | REQ_F_BUFFER_SELECT)))
 545                 return -EINVAL;
 546         if (sqe->rw_flags || sqe->splice_fd_in)
 547                 return -EINVAL;
 548
 549         up->offset = READ_ONCE(sqe->off);
 550         up->nr_args = READ_ONCE(sqe->len);
 551         if (!up->nr_args)
 552                 return -EINVAL;
 553         up->arg = READ_ONCE(sqe->addr);
 554         return 0;
 555 }
 556
 557 static int io_files_update_with_index_alloc(struct io_kiocb *req,
 558                                             unsigned int issue_flags)
 559 {
 560         struct io_rsrc_update *up = io_kiocb_to_cmd(req, struct io_rsrc_update);
 561         __s32 __user *fds = u64_to_user_ptr(up->arg);
 562         unsigned int done;
 563         struct file *file;
 564         int ret, fd;
 565
 566         if (!req->ctx->file_data)
 567                 return -ENXIO;
 568
 569         for (done = 0; done < up->nr_args; done++) {
 570                 if (copy_from_user(&fd, &fds[done], sizeof(fd))) {
 571                         ret = -EFAULT;
 572                         break;
 573                 }
 574
 575                 file = fget(fd);
 576                 if (!file) {
 577                         ret = -EBADF;
 578                         break;
 579                 }
 580                 ret = io_fixed_fd_install(req, issue_flags, file,
 581                                           IORING_FILE_INDEX_ALLOC);
 582                 if (ret < 0)
 583                         break;
 584                 if (copy_to_user(&fds[done], &ret, sizeof(ret))) {
 585                         __io_close_fixed(req->ctx, issue_flags, ret);
 586                         ret = -EFAULT;
 587                         break;
 588                 }
 589         }
 590
 591         if (done)
 592                 return done;
 593         return ret;
 594 }
 595
 596 int io_files_update(struct io_kiocb *req, unsigned int issue_flags)
 597 {
 598         struct io_rsrc_update *up = io_kiocb_to_cmd(req, struct io_rsrc_update);
 599         struct io_ring_ctx *ctx = req->ctx;
 600         struct io_uring_rsrc_update2 up2;
 601         int ret;
 602
 603         up2.offset = up->offset;
 604         up2.data = up->arg;
 605         up2.nr = 0;
 606         up2.tags = 0;
 607         up2.resv = 0;
 608         up2.resv2 = 0;
 609
 610         if (up->offset == IORING_FILE_INDEX_ALLOC) {
 611                 ret = io_files_update_with_index_alloc(req, issue_flags);
 612         } else {
 613                 io_ring_submit_lock(ctx, issue_flags);
 614                 ret = __io_register_rsrc_update(ctx, IORING_RSRC_FILE,
 615                                                 &up2, up->nr_args);
 616                 io_ring_submit_unlock(ctx, issue_flags);
 617         }
 618
 619         if (ret < 0)
 620                 req_set_fail(req);
 621         io_req_set_res(req, ret, 0);
 622         return IOU_OK;
 623 }
 624
 625 int io_queue_rsrc_removal(struct io_rsrc_data *data, unsigned idx, void *rsrc)
 626 {
 627         struct io_ring_ctx *ctx = data->ctx;
 628         struct io_rsrc_node *node = ctx->rsrc_node;
 629         u64 *tag_slot = io_get_tag_slot(data, idx);
 630
 631         ctx->rsrc_node = io_rsrc_node_alloc(ctx);
 632         if (unlikely(!ctx->rsrc_node)) {
 633                 ctx->rsrc_node = node;
 634                 return -ENOMEM;
 635         }
 636
 637         node->item.rsrc = rsrc;
 638         node->type = data->rsrc_type;
 639         node->item.tag = *tag_slot;
 640         *tag_slot = 0;
 641         list_add_tail(&node->node, &ctx->rsrc_ref_list);
 642         io_put_rsrc_node(ctx, node);
 643         return 0;
 644 }
 645
 646 void __io_sqe_files_unregister(struct io_ring_ctx *ctx)
 647 {
 648         int i;
 649
 650         for (i = 0; i < ctx->nr_user_files; i++) {
 651                 struct file *file = io_file_from_index(&ctx->file_table, i);
 652
 653                 if (!file)
 654                         continue;
 655                 io_file_bitmap_clear(&ctx->file_table, i);
 656                 fput(file);
 657         }
 658
 659         io_free_file_tables(&ctx->file_table);
 660         io_file_table_set_alloc_range(ctx, 0, 0);
 661         io_rsrc_data_free(ctx->file_data);
 662         ctx->file_data = NULL;
 663         ctx->nr_user_files = 0;
 664 }
 665
 666 int io_sqe_files_unregister(struct io_ring_ctx *ctx)
 667 {
 668         unsigned nr = ctx->nr_user_files;
 669         int ret;
 670
 671         if (!ctx->file_data)
 672                 return -ENXIO;
 673
 674         /*
 675          * Quiesce may unlock ->uring_lock, and while it's not held
 676          * prevent new requests using the table.
 677          */
 678         ctx->nr_user_files = 0;
 679         ret = io_rsrc_ref_quiesce(ctx->file_data, ctx);
 680         ctx->nr_user_files = nr;
 681         if (!ret)
 682                 __io_sqe_files_unregister(ctx);
 683         return ret;
 684 }
 685
 686 int io_sqe_files_register(struct io_ring_ctx *ctx, void __user *arg,
 687                           unsigned nr_args, u64 __user *tags)
 688 {
 689         __s32 __user *fds = (__s32 __user *) arg;
 690         struct file *file;
 691         int fd, ret;
 692         unsigned i;
 693
 694         if (ctx->file_data)
 695                 return -EBUSY;
 696         if (!nr_args)
 697                 return -EINVAL;
 698         if (nr_args > IORING_MAX_FIXED_FILES)
 699                 return -EMFILE;
 700         if (nr_args > rlimit(RLIMIT_NOFILE))
 701                 return -EMFILE;
 702         ret = io_rsrc_data_alloc(ctx, IORING_RSRC_FILE, tags, nr_args,
 703                                  &ctx->file_data);
 704         if (ret)
 705                 return ret;
 706
 707         if (!io_alloc_file_tables(&ctx->file_table, nr_args)) {
 708                 io_rsrc_data_free(ctx->file_data);
 709                 ctx->file_data = NULL;
 710                 return -ENOMEM;
 711         }
 712
 713         for (i = 0; i < nr_args; i++, ctx->nr_user_files++) {
 714                 struct io_fixed_file *file_slot;
 715
 716                 if (fds && copy_from_user(&fd, &fds[i], sizeof(fd))) {
 717                         ret = -EFAULT;
 718                         goto fail;
 719                 }
 720                 /* allow sparse sets */
 721                 if (!fds || fd == -1) {
 722                         ret = -EINVAL;
 723                         if (unlikely(*io_get_tag_slot(ctx->file_data, i)))
 724                                 goto fail;
 725                         continue;
 726                 }
 727
 728                 file = fget(fd);
 729                 ret = -EBADF;
 730                 if (unlikely(!file))
 731                         goto fail;
 732
 733                 /*
 734                  * Don't allow io_uring instances to be registered.
 735                  */
 736                 if (io_is_uring_fops(file)) {
 737                         fput(file);
 738                         goto fail;
 739                 }
 740                 file_slot = io_fixed_file_slot(&ctx->file_table, i);
 741                 io_fixed_file_set(file_slot, file);
 742                 io_file_bitmap_set(&ctx->file_table, i);
 743         }
 744
 745         /* default it to the whole table */
 746         io_file_table_set_alloc_range(ctx, 0, ctx->nr_user_files);
 747         return 0;
 748 fail:
 749         __io_sqe_files_unregister(ctx);
 750         return ret;
 751 }
 752
 753 static void io_rsrc_buf_put(struct io_ring_ctx *ctx, struct io_rsrc_put *prsrc)
 754 {
 755         io_buffer_unmap(ctx, &prsrc->buf);
 756         prsrc->buf = NULL;
 757 }
 758
 759 void __io_sqe_buffers_unregister(struct io_ring_ctx *ctx)
 760 {
 761         unsigned int i;
 762
 763         for (i = 0; i < ctx->nr_user_bufs; i++)
 764                 io_buffer_unmap(ctx, &ctx->user_bufs[i]);
 765         kfree(ctx->user_bufs);
 766         io_rsrc_data_free(ctx->buf_data);
 767         ctx->user_bufs = NULL;
 768         ctx->buf_data = NULL;
 769         ctx->nr_user_bufs = 0;
 770 }
 771
 772 int io_sqe_buffers_unregister(struct io_ring_ctx *ctx)
 773 {
 774         unsigned nr = ctx->nr_user_bufs;
 775         int ret;
 776
 777         if (!ctx->buf_data)
 778                 return -ENXIO;
 779
 780         /*
 781          * Quiesce may unlock ->uring_lock, and while it's not held
 782          * prevent new requests using the table.
 783          */
 784         ctx->nr_user_bufs = 0;
 785         ret = io_rsrc_ref_quiesce(ctx->buf_data, ctx);
 786         ctx->nr_user_bufs = nr;
 787         if (!ret)
 788                 __io_sqe_buffers_unregister(ctx);
 789         return ret;
 790 }
 791
 792 /*
 793  * Not super efficient, but this is just a registration time. And we do cache
 794  * the last compound head, so generally we'll only do a full search if we don't
 795  * match that one.
 796  *
 797  * We check if the given compound head page has already been accounted, to
 798  * avoid double accounting it. This allows us to account the full size of the
 799  * page, not just the constituent pages of a huge page.
 800  */
 801 static bool headpage_already_acct(struct io_ring_ctx *ctx, struct page **pages,
 802                                   int nr_pages, struct page *hpage)
 803 {
 804         int i, j;
 805
 806         /* check current page array */
 807         for (i = 0; i < nr_pages; i++) {
 808                 if (!PageCompound(pages[i]))
 809                         continue;
 810                 if (compound_head(pages[i]) == hpage)
 811                         return true;
 812         }
 813
 814         /* check previously registered pages */
 815         for (i = 0; i < ctx->nr_user_bufs; i++) {
 816                 struct io_mapped_ubuf *imu = ctx->user_bufs[i];
 817
 818                 for (j = 0; j < imu->nr_bvecs; j++) {
 819                         if (!PageCompound(imu->bvec[j].bv_page))
 820                                 continue;
 821                         if (compound_head(imu->bvec[j].bv_page) == hpage)
 822                                 return true;
 823                 }
 824         }
 825
 826         return false;
 827 }
 828
 829 static int io_buffer_account_pin(struct io_ring_ctx *ctx, struct page **pages,
 830                                  int nr_pages, struct io_mapped_ubuf *imu,
 831                                  struct page **last_hpage)
 832 {
 833         int i, ret;
 834
 835         imu->acct_pages = 0;
 836         for (i = 0; i < nr_pages; i++) {
 837                 if (!PageCompound(pages[i])) {
 838                         imu->acct_pages++;
 839                 } else {
 840                         struct page *hpage;
 841
 842                         hpage = compound_head(pages[i]);
 843                         if (hpage == *last_hpage)
 844                                 continue;
 845                         *last_hpage = hpage;
 846                         if (headpage_already_acct(ctx, pages, i, hpage))
 847                                 continue;
 848                         imu->acct_pages += page_size(hpage) >> PAGE_SHIFT;
 849                 }
 850         }
 851
 852         if (!imu->acct_pages)
 853                 return 0;
 854
 855         ret = io_account_mem(ctx, imu->acct_pages);
 856         if (ret)
 857                 imu->acct_pages = 0;
 858         return ret;
 859 }
 860
 861 static bool io_do_coalesce_buffer(struct page ***pages, int *nr_pages,
 862                                 struct io_imu_folio_data *data, int nr_folios)
 863 {
 864         struct page **page_array = *pages, **new_array = NULL;
 865         int nr_pages_left = *nr_pages, i, j;
 866
 867         /* Store head pages only*/
 868         new_array = kvmalloc_array(nr_folios, sizeof(struct page *),
 869                                         GFP_KERNEL);
 870         if (!new_array)
 871                 return false;
 872
 873         new_array[0] = compound_head(page_array[0]);
 874         /*
 875          * The pages are bound to the folio, it doesn't
 876          * actually unpin them but drops all but one reference,
 877          * which is usually put down by io_buffer_unmap().
 878          * Note, needs a better helper.
 879          */
 880         if (data->nr_pages_head > 1)
 881                 unpin_user_pages(&page_array[1], data->nr_pages_head - 1);
 882
 883         j = data->nr_pages_head;
 884         nr_pages_left -= data->nr_pages_head;
 885         for (i = 1; i < nr_folios; i++) {
 886                 unsigned int nr_unpin;
 887
 888                 new_array[i] = page_array[j];
 889                 nr_unpin = min_t(unsigned int, nr_pages_left - 1,
 890                                         data->nr_pages_mid - 1);
 891                 if (nr_unpin)
 892                         unpin_user_pages(&page_array[j+1], nr_unpin);
 893                 j += data->nr_pages_mid;
 894                 nr_pages_left -= data->nr_pages_mid;
 895         }
 896         kvfree(page_array);
 897         *pages = new_array;
 898         *nr_pages = nr_folios;
 899         return true;
 900 }
 901
 902 static bool io_try_coalesce_buffer(struct page ***pages, int *nr_pages,
 903                                          struct io_imu_folio_data *data)
 904 {
 905         struct page **page_array = *pages;
 906         struct folio *folio = page_folio(page_array[0]);
 907         unsigned int count = 1, nr_folios = 1;
 908         int i;
 909
 910         if (*nr_pages <= 1)
 911                 return false;
 912
 913         data->nr_pages_mid = folio_nr_pages(folio);
 914         if (data->nr_pages_mid == 1)
 915                 return false;
 916
 917         data->folio_shift = folio_shift(folio);
 918         /*
 919          * Check if pages are contiguous inside a folio, and all folios have
 920          * the same page count except for the head and tail.
 921          */
 922         for (i = 1; i < *nr_pages; i++) {
 923                 if (page_folio(page_array[i]) == folio &&
 924                         page_array[i] == page_array[i-1] + 1) {
 925                         count++;
 926                         continue;
 927                 }
 928
 929                 if (nr_folios == 1) {
 930                         if (folio_page_idx(folio, page_array[i-1]) !=
 931                                 data->nr_pages_mid - 1)
 932                                 return false;
 933
 934                         data->nr_pages_head = count;
 935                 } else if (count != data->nr_pages_mid) {
 936                         return false;
 937                 }
 938
 939                 folio = page_folio(page_array[i]);
 940                 if (folio_size(folio) != (1UL << data->folio_shift) ||
 941                         folio_page_idx(folio, page_array[i]) != 0)
 942                         return false;
 943
 944                 count = 1;
 945                 nr_folios++;
 946         }
 947         if (nr_folios == 1)
 948                 data->nr_pages_head = count;
 949
 950         return io_do_coalesce_buffer(pages, nr_pages, data, nr_folios);
 951 }
 952
 953 static int io_sqe_buffer_register(struct io_ring_ctx *ctx, struct iovec *iov,
 954                                   struct io_mapped_ubuf **pimu,
 955                                   struct page **last_hpage)
 956 {
 957         struct io_mapped_ubuf *imu = NULL;
 958         struct page **pages = NULL;
 959         unsigned long off;
 960         size_t size;
 961         int ret, nr_pages, i;
 962         struct io_imu_folio_data data;
 963         bool coalesced;
 964
 965         *pimu = (struct io_mapped_ubuf *)&dummy_ubuf;
 966         if (!iov->iov_base)
 967                 return 0;
 968
 969         ret = -ENOMEM;
 970         pages = io_pin_pages((unsigned long) iov->iov_base, iov->iov_len,
 971                                 &nr_pages);
 972         if (IS_ERR(pages)) {
 973                 ret = PTR_ERR(pages);
 974                 pages = NULL;
 975                 goto done;
 976         }
 977
 978         /* If it's huge page(s), try to coalesce them into fewer bvec entries */
 979         coalesced = io_try_coalesce_buffer(&pages, &nr_pages, &data);
 980
 981         imu = kvmalloc(struct_size(imu, bvec, nr_pages), GFP_KERNEL);
 982         if (!imu)
 983                 goto done;
 984
 985         ret = io_buffer_account_pin(ctx, pages, nr_pages, imu, last_hpage);
 986         if (ret) {
 987                 unpin_user_pages(pages, nr_pages);
 988                 goto done;
 989         }
 990
 991         size = iov->iov_len;
 992         /* store original address for later verification */
 993         imu->ubuf = (unsigned long) iov->iov_base;
 994         imu->len = iov->iov_len;
 995         imu->nr_bvecs = nr_pages;
 996         imu->folio_shift = PAGE_SHIFT;
 997         if (coalesced)
 998                 imu->folio_shift = data.folio_shift;
 999         refcount_set(&imu->refs, 1);
1000         off = (unsigned long) iov->iov_base & ((1UL << imu->folio_shift) - 1);
1001         *pimu = imu;
1002         ret = 0;
1003
1004         for (i = 0; i < nr_pages; i++) {
1005                 size_t vec_len;
1006
1007                 vec_len = min_t(size_t, size, (1UL << imu->folio_shift) - off);
1008                 bvec_set_page(&imu->bvec[i], pages[i], vec_len, off);
1009                 off = 0;
1010                 size -= vec_len;
1011         }
1012 done:
1013         if (ret)
1014                 kvfree(imu);
1015         kvfree(pages);
1016         return ret;
1017 }
1018
1019 static int io_buffers_map_alloc(struct io_ring_ctx *ctx, unsigned int nr_args)
1020 {
1021         ctx->user_bufs = kcalloc(nr_args, sizeof(*ctx->user_bufs), GFP_KERNEL);
1022         return ctx->user_bufs ? 0 : -ENOMEM;
1023 }
1024
1025 int io_sqe_buffers_register(struct io_ring_ctx *ctx, void __user *arg,
1026                             unsigned int nr_args, u64 __user *tags)
1027 {
1028         struct page *last_hpage = NULL;
1029         struct io_rsrc_data *data;
1030         struct iovec fast_iov, *iov = &fast_iov;
1031         const struct iovec __user *uvec;
1032         int i, ret;
1033
1034         BUILD_BUG_ON(IORING_MAX_REG_BUFFERS >= (1u << 16));
1035
1036         if (ctx->user_bufs)
1037                 return -EBUSY;
1038         if (!nr_args || nr_args > IORING_MAX_REG_BUFFERS)
1039                 return -EINVAL;
1040         ret = io_rsrc_data_alloc(ctx, IORING_RSRC_BUFFER, tags, nr_args, &data);
1041         if (ret)
1042                 return ret;
1043         ret = io_buffers_map_alloc(ctx, nr_args);
1044         if (ret) {
1045                 io_rsrc_data_free(data);
1046                 return ret;
1047         }
1048
1049         if (!arg)
1050                 memset(iov, 0, sizeof(*iov));
1051
1052         for (i = 0; i < nr_args; i++, ctx->nr_user_bufs++) {
1053                 if (arg) {
1054                         uvec = (struct iovec __user *) arg;
1055                         iov = iovec_from_user(uvec, 1, 1, &fast_iov, ctx->compat);
1056                         if (IS_ERR(iov)) {
1057                                 ret = PTR_ERR(iov);
1058                                 break;
1059                         }
1060                         ret = io_buffer_validate(iov);
1061                         if (ret)
1062                                 break;
1063                         if (ctx->compat)
1064                                 arg += sizeof(struct compat_iovec);
1065                         else
1066                                 arg += sizeof(struct iovec);
1067                 }
1068
1069                 if (!iov->iov_base && *io_get_tag_slot(data, i)) {
1070                         ret = -EINVAL;
1071                         break;
1072                 }
1073
1074                 ret = io_sqe_buffer_register(ctx, iov, &ctx->user_bufs[i],
1075                                              &last_hpage);
1076                 if (ret)
1077                         break;
1078         }
1079
1080         WARN_ON_ONCE(ctx->buf_data);
1081
1082         ctx->buf_data = data;
1083         if (ret)
1084                 __io_sqe_buffers_unregister(ctx);
1085         return ret;
1086 }
1087
1088 int io_import_fixed(int ddir, struct iov_iter *iter,
1089                            struct io_mapped_ubuf *imu,
1090                            u64 buf_addr, size_t len)
1091 {
1092         u64 buf_end;
1093         size_t offset;
1094
1095         if (WARN_ON_ONCE(!imu))
1096                 return -EFAULT;
1097         if (unlikely(check_add_overflow(buf_addr, (u64)len, &buf_end)))
1098                 return -EFAULT;
1099         /* not inside the mapped region */
1100         if (unlikely(buf_addr < imu->ubuf || buf_end > (imu->ubuf + imu->len)))
1101                 return -EFAULT;
1102
1103         /*
1104          * Might not be a start of buffer, set size appropriately
1105          * and advance us to the beginning.
1106          */
1107         offset = buf_addr - imu->ubuf;
1108         iov_iter_bvec(iter, ddir, imu->bvec, imu->nr_bvecs, offset + len);
1109
1110         if (offset) {
1111                 /*
1112                  * Don't use iov_iter_advance() here, as it's really slow for
1113                  * using the latter parts of a big fixed buffer - it iterates
1114                  * over each segment manually. We can cheat a bit here, because
1115                  * we know that:
1116                  *
1117                  * 1) it's a BVEC iter, we set it up
1118                  * 2) all bvecs are the same in size, except potentially the
1119                  *    first and last bvec
1120                  *
1121                  * So just find our index, and adjust the iterator afterwards.
1122                  * If the offset is within the first bvec (or the whole first
1123                  * bvec, just use iov_iter_advance(). This makes it easier
1124                  * since we can just skip the first segment, which may not
1125                  * be folio_size aligned.
1126                  */
1127                 const struct bio_vec *bvec = imu->bvec;
1128
1129                 if (offset < bvec->bv_len) {
1130                         iter->bvec = bvec;
1131                         iter->count -= offset;
1132                         iter->iov_offset = offset;
1133                 } else {
1134                         unsigned long seg_skip;
1135
1136                         /* skip first vec */
1137                         offset -= bvec->bv_len;
1138                         seg_skip = 1 + (offset >> imu->folio_shift);
1139
1140                         iter->bvec = bvec + seg_skip;
1141                         iter->nr_segs -= seg_skip;
1142                         iter->count -= bvec->bv_len + offset;
1143                         iter->iov_offset = offset & ((1UL << imu->folio_shift) - 1);
1144                 }
1145         }
1146
1147         return 0;
1148 }
1149
1150 static int io_clone_buffers(struct io_ring_ctx *ctx, struct io_ring_ctx *src_ctx)
1151 {
1152         struct io_mapped_ubuf **user_bufs;
1153         struct io_rsrc_data *data;
1154         int i, ret, nbufs;
1155
1156         /*
1157          * Drop our own lock here. We'll setup the data we need and reference
1158          * the source buffers, then re-grab, check, and assign at the end.
1159          */
1160         mutex_unlock(&ctx->uring_lock);
1161
1162         mutex_lock(&src_ctx->uring_lock);
1163         ret = -ENXIO;
1164         nbufs = src_ctx->nr_user_bufs;
1165         if (!nbufs)
1166                 goto out_unlock;
1167         ret = io_rsrc_data_alloc(ctx, IORING_RSRC_BUFFER, NULL, nbufs, &data);
1168         if (ret)
1169                 goto out_unlock;
1170
1171         ret = -ENOMEM;
1172         user_bufs = kcalloc(nbufs, sizeof(*ctx->user_bufs), GFP_KERNEL);
1173         if (!user_bufs)
1174                 goto out_free_data;
1175
1176         for (i = 0; i < nbufs; i++) {
1177                 struct io_mapped_ubuf *src = src_ctx->user_bufs[i];
1178
1179                 refcount_inc(&src->refs);
1180                 user_bufs[i] = src;
1181         }
1182
1183         /* Have a ref on the bufs now, drop src lock and re-grab our own lock */
1184         mutex_unlock(&src_ctx->uring_lock);
1185         mutex_lock(&ctx->uring_lock);
1186         if (!ctx->user_bufs) {
1187                 ctx->user_bufs = user_bufs;
1188                 ctx->buf_data = data;
1189                 ctx->nr_user_bufs = nbufs;
1190                 return 0;
1191         }
1192
1193         /* someone raced setting up buffers, dump ours */
1194         for (i = 0; i < nbufs; i++)
1195                 io_buffer_unmap(ctx, &user_bufs[i]);
1196         io_rsrc_data_free(data);
1197         kfree(user_bufs);
1198         return -EBUSY;
1199 out_free_data:
1200         io_rsrc_data_free(data);
1201 out_unlock:
1202         mutex_unlock(&src_ctx->uring_lock);
1203         mutex_lock(&ctx->uring_lock);
1204         return ret;
1205 }
1206
1207 /*
1208  * Copy the registered buffers from the source ring whose file descriptor
1209  * is given in the src_fd to the current ring. This is identical to registering
1210  * the buffers with ctx, except faster as mappings already exist.
1211  *
1212  * Since the memory is already accounted once, don't account it again.
1213  */
1214 int io_register_clone_buffers(struct io_ring_ctx *ctx, void __user *arg)
1215 {
1216         struct io_uring_clone_buffers buf;
1217         bool registered_src;
1218         struct file *file;
1219         int ret;
1220
1221         if (ctx->user_bufs || ctx->nr_user_bufs)
1222                 return -EBUSY;
1223         if (copy_from_user(&buf, arg, sizeof(buf)))
1224                 return -EFAULT;
1225         if (buf.flags & ~IORING_REGISTER_SRC_REGISTERED)
1226                 return -EINVAL;
1227         if (memchr_inv(buf.pad, 0, sizeof(buf.pad)))
1228                 return -EINVAL;
1229
1230         registered_src = (buf.flags & IORING_REGISTER_SRC_REGISTERED) != 0;
1231         file = io_uring_register_get_file(buf.src_fd, registered_src);
1232         if (IS_ERR(file))
1233                 return PTR_ERR(file);
1234         ret = io_clone_buffers(ctx, file->private_data);
1235         if (!registered_src)
1236                 fput(file);
1237         return ret;
1238 }