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