1 // SPDX-License-Identifier: GPL-2.0
2 #include <linux/kernel.h>
3 #include <linux/errno.h>
5 #include <linux/file.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>
13 #include <uapi/linux/io_uring.h>
16 #include "openclose.h"
19 struct io_rsrc_update {
26 static int io_sqe_buffer_register(struct io_ring_ctx *ctx, struct iovec *iov,
27 struct io_mapped_ubuf **pimu,
28 struct page **last_hpage);
31 #define IORING_MAX_FIXED_FILES (1U << 20)
32 #define IORING_MAX_REG_BUFFERS (1U << 14)
34 int __io_account_mem(struct user_struct *user, unsigned long nr_pages)
36 unsigned long page_limit, cur_pages, new_pages;
41 /* Don't allow more pages than we can safely lock */
42 page_limit = rlimit(RLIMIT_MEMLOCK) >> PAGE_SHIFT;
44 cur_pages = atomic_long_read(&user->locked_vm);
46 new_pages = cur_pages + nr_pages;
47 if (new_pages > page_limit)
49 } while (!atomic_long_try_cmpxchg(&user->locked_vm,
50 &cur_pages, new_pages));
54 static void io_unaccount_mem(struct io_ring_ctx *ctx, unsigned long nr_pages)
57 __io_unaccount_mem(ctx->user, nr_pages);
60 atomic64_sub(nr_pages, &ctx->mm_account->pinned_vm);
63 static int io_account_mem(struct io_ring_ctx *ctx, unsigned long nr_pages)
68 ret = __io_account_mem(ctx->user, nr_pages);
74 atomic64_add(nr_pages, &ctx->mm_account->pinned_vm);
79 static int io_copy_iov(struct io_ring_ctx *ctx, struct iovec *dst,
80 void __user *arg, unsigned index)
82 struct iovec __user *src;
86 struct compat_iovec __user *ciovs;
87 struct compat_iovec ciov;
89 ciovs = (struct compat_iovec __user *) arg;
90 if (copy_from_user(&ciov, &ciovs[index], sizeof(ciov)))
93 dst->iov_base = u64_to_user_ptr((u64)ciov.iov_base);
94 dst->iov_len = ciov.iov_len;
98 src = (struct iovec __user *) arg;
99 if (copy_from_user(dst, &src[index], sizeof(*dst)))
104 static int io_buffer_validate(struct iovec *iov)
106 unsigned long tmp, acct_len = iov->iov_len + (PAGE_SIZE - 1);
109 * Don't impose further limits on the size and buffer
110 * constraints here, we'll -EINVAL later when IO is
111 * submitted if they are wrong.
114 return iov->iov_len ? -EFAULT : 0;
118 /* arbitrary limit, but we need something */
119 if (iov->iov_len > SZ_1G)
122 if (check_add_overflow((unsigned long)iov->iov_base, acct_len, &tmp))
128 static void io_buffer_unmap(struct io_ring_ctx *ctx, struct io_mapped_ubuf **slot)
130 struct io_mapped_ubuf *imu = *slot;
133 if (imu != ctx->dummy_ubuf) {
134 for (i = 0; i < imu->nr_bvecs; i++)
135 unpin_user_page(imu->bvec[i].bv_page);
137 io_unaccount_mem(ctx, imu->acct_pages);
143 static void io_rsrc_put_work(struct io_rsrc_node *node)
145 struct io_rsrc_data *data = node->rsrc_data;
146 struct io_rsrc_put *prsrc = &node->item;
149 io_post_aux_cqe(data->ctx, prsrc->tag, 0, 0);
150 data->do_put(data->ctx, prsrc);
153 void io_rsrc_node_destroy(struct io_ring_ctx *ctx, struct io_rsrc_node *node)
155 if (!io_alloc_cache_put(&ctx->rsrc_node_cache, &node->cache))
159 void io_rsrc_node_ref_zero(struct io_rsrc_node *node)
160 __must_hold(&node->rsrc_data->ctx->uring_lock)
162 struct io_ring_ctx *ctx = node->rsrc_data->ctx;
164 while (!list_empty(&ctx->rsrc_ref_list)) {
165 node = list_first_entry(&ctx->rsrc_ref_list,
166 struct io_rsrc_node, node);
167 /* recycle ref nodes in order */
170 list_del(&node->node);
172 if (likely(!node->empty))
173 io_rsrc_put_work(node);
174 io_rsrc_node_destroy(ctx, node);
176 if (list_empty(&ctx->rsrc_ref_list) && unlikely(ctx->rsrc_quiesce))
177 wake_up_all(&ctx->rsrc_quiesce_wq);
180 struct io_rsrc_node *io_rsrc_node_alloc(struct io_ring_ctx *ctx)
182 struct io_rsrc_node *ref_node;
183 struct io_cache_entry *entry;
185 entry = io_alloc_cache_get(&ctx->rsrc_node_cache);
187 ref_node = container_of(entry, struct io_rsrc_node, cache);
189 ref_node = kzalloc(sizeof(*ref_node), GFP_KERNEL);
194 ref_node->rsrc_data = NULL;
200 __cold static int io_rsrc_ref_quiesce(struct io_rsrc_data *data,
201 struct io_ring_ctx *ctx)
203 struct io_rsrc_node *backup;
207 /* As We may drop ->uring_lock, other task may have started quiesce */
211 backup = io_rsrc_node_alloc(ctx);
214 ctx->rsrc_node->empty = true;
215 ctx->rsrc_node->rsrc_data = data;
216 list_add_tail(&ctx->rsrc_node->node, &ctx->rsrc_ref_list);
217 io_put_rsrc_node(ctx, ctx->rsrc_node);
218 ctx->rsrc_node = backup;
220 if (list_empty(&ctx->rsrc_ref_list))
223 if (ctx->flags & IORING_SETUP_DEFER_TASKRUN) {
224 atomic_set(&ctx->cq_wait_nr, 1);
229 data->quiesce = true;
231 prepare_to_wait(&ctx->rsrc_quiesce_wq, &we, TASK_INTERRUPTIBLE);
232 mutex_unlock(&ctx->uring_lock);
234 ret = io_run_task_work_sig(ctx);
236 mutex_lock(&ctx->uring_lock);
237 if (list_empty(&ctx->rsrc_ref_list))
243 __set_current_state(TASK_RUNNING);
244 mutex_lock(&ctx->uring_lock);
246 } while (!list_empty(&ctx->rsrc_ref_list));
248 finish_wait(&ctx->rsrc_quiesce_wq, &we);
249 data->quiesce = false;
252 if (ctx->flags & IORING_SETUP_DEFER_TASKRUN) {
253 atomic_set(&ctx->cq_wait_nr, 0);
259 static void io_free_page_table(void **table, size_t size)
261 unsigned i, nr_tables = DIV_ROUND_UP(size, PAGE_SIZE);
263 for (i = 0; i < nr_tables; i++)
268 static void io_rsrc_data_free(struct io_rsrc_data *data)
270 size_t size = data->nr * sizeof(data->tags[0][0]);
273 io_free_page_table((void **)data->tags, size);
277 static __cold void **io_alloc_page_table(size_t size)
279 unsigned i, nr_tables = DIV_ROUND_UP(size, PAGE_SIZE);
280 size_t init_size = size;
283 table = kcalloc(nr_tables, sizeof(*table), GFP_KERNEL_ACCOUNT);
287 for (i = 0; i < nr_tables; i++) {
288 unsigned int this_size = min_t(size_t, size, PAGE_SIZE);
290 table[i] = kzalloc(this_size, GFP_KERNEL_ACCOUNT);
292 io_free_page_table(table, init_size);
300 __cold static int io_rsrc_data_alloc(struct io_ring_ctx *ctx,
301 rsrc_put_fn *do_put, u64 __user *utags,
302 unsigned nr, struct io_rsrc_data **pdata)
304 struct io_rsrc_data *data;
308 data = kzalloc(sizeof(*data), GFP_KERNEL);
311 data->tags = (u64 **)io_alloc_page_table(nr * sizeof(data->tags[0][0]));
319 data->do_put = do_put;
322 for (i = 0; i < nr; i++) {
323 u64 *tag_slot = io_get_tag_slot(data, i);
325 if (copy_from_user(tag_slot, &utags[i],
333 io_rsrc_data_free(data);
337 static int __io_sqe_files_update(struct io_ring_ctx *ctx,
338 struct io_uring_rsrc_update2 *up,
341 u64 __user *tags = u64_to_user_ptr(up->tags);
342 __s32 __user *fds = u64_to_user_ptr(up->data);
343 struct io_rsrc_data *data = ctx->file_data;
344 struct io_fixed_file *file_slot;
351 if (up->offset + nr_args > ctx->nr_user_files)
354 for (done = 0; done < nr_args; done++) {
357 if ((tags && copy_from_user(&tag, &tags[done], sizeof(tag))) ||
358 copy_from_user(&fd, &fds[done], sizeof(fd))) {
362 if ((fd == IORING_REGISTER_FILES_SKIP || fd == -1) && tag) {
366 if (fd == IORING_REGISTER_FILES_SKIP)
369 i = array_index_nospec(up->offset + done, ctx->nr_user_files);
370 file_slot = io_fixed_file_slot(&ctx->file_table, i);
372 if (file_slot->file_ptr) {
373 file = (struct file *)(file_slot->file_ptr & FFS_MASK);
374 err = io_queue_rsrc_removal(data, i, file);
377 file_slot->file_ptr = 0;
378 io_file_bitmap_clear(&ctx->file_table, i);
387 * Don't allow io_uring instances to be registered. If
388 * UNIX isn't enabled, then this causes a reference
389 * cycle and this instance can never get freed. If UNIX
390 * is enabled we'll handle it just fine, but there's
391 * still no point in allowing a ring fd as it doesn't
392 * support regular read/write anyway.
394 if (io_is_uring_fops(file)) {
399 err = io_scm_file_account(ctx, file);
404 *io_get_tag_slot(data, i) = tag;
405 io_fixed_file_set(file_slot, file);
406 io_file_bitmap_set(&ctx->file_table, i);
409 return done ? done : err;
412 static int __io_sqe_buffers_update(struct io_ring_ctx *ctx,
413 struct io_uring_rsrc_update2 *up,
414 unsigned int nr_args)
416 u64 __user *tags = u64_to_user_ptr(up->tags);
417 struct iovec iov, __user *iovs = u64_to_user_ptr(up->data);
418 struct page *last_hpage = NULL;
424 if (up->offset + nr_args > ctx->nr_user_bufs)
427 for (done = 0; done < nr_args; done++) {
428 struct io_mapped_ubuf *imu;
431 err = io_copy_iov(ctx, &iov, iovs, done);
434 if (tags && copy_from_user(&tag, &tags[done], sizeof(tag))) {
438 err = io_buffer_validate(&iov);
441 if (!iov.iov_base && tag) {
445 err = io_sqe_buffer_register(ctx, &iov, &imu, &last_hpage);
449 i = array_index_nospec(up->offset + done, ctx->nr_user_bufs);
450 if (ctx->user_bufs[i] != ctx->dummy_ubuf) {
451 err = io_queue_rsrc_removal(ctx->buf_data, i,
454 io_buffer_unmap(ctx, &imu);
457 ctx->user_bufs[i] = ctx->dummy_ubuf;
460 ctx->user_bufs[i] = imu;
461 *io_get_tag_slot(ctx->buf_data, i) = tag;
463 return done ? done : err;
466 static int __io_register_rsrc_update(struct io_ring_ctx *ctx, unsigned type,
467 struct io_uring_rsrc_update2 *up,
472 lockdep_assert_held(&ctx->uring_lock);
474 if (check_add_overflow(up->offset, nr_args, &tmp))
478 case IORING_RSRC_FILE:
479 return __io_sqe_files_update(ctx, up, nr_args);
480 case IORING_RSRC_BUFFER:
481 return __io_sqe_buffers_update(ctx, up, nr_args);
486 int io_register_files_update(struct io_ring_ctx *ctx, void __user *arg,
489 struct io_uring_rsrc_update2 up;
493 memset(&up, 0, sizeof(up));
494 if (copy_from_user(&up, arg, sizeof(struct io_uring_rsrc_update)))
496 if (up.resv || up.resv2)
498 return __io_register_rsrc_update(ctx, IORING_RSRC_FILE, &up, nr_args);
501 int io_register_rsrc_update(struct io_ring_ctx *ctx, void __user *arg,
502 unsigned size, unsigned type)
504 struct io_uring_rsrc_update2 up;
506 if (size != sizeof(up))
508 if (copy_from_user(&up, arg, sizeof(up)))
510 if (!up.nr || up.resv || up.resv2)
512 return __io_register_rsrc_update(ctx, type, &up, up.nr);
515 __cold int io_register_rsrc(struct io_ring_ctx *ctx, void __user *arg,
516 unsigned int size, unsigned int type)
518 struct io_uring_rsrc_register rr;
520 /* keep it extendible */
521 if (size != sizeof(rr))
524 memset(&rr, 0, sizeof(rr));
525 if (copy_from_user(&rr, arg, size))
527 if (!rr.nr || rr.resv2)
529 if (rr.flags & ~IORING_RSRC_REGISTER_SPARSE)
533 case IORING_RSRC_FILE:
534 if (rr.flags & IORING_RSRC_REGISTER_SPARSE && rr.data)
536 return io_sqe_files_register(ctx, u64_to_user_ptr(rr.data),
537 rr.nr, u64_to_user_ptr(rr.tags));
538 case IORING_RSRC_BUFFER:
539 if (rr.flags & IORING_RSRC_REGISTER_SPARSE && rr.data)
541 return io_sqe_buffers_register(ctx, u64_to_user_ptr(rr.data),
542 rr.nr, u64_to_user_ptr(rr.tags));
547 int io_files_update_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
549 struct io_rsrc_update *up = io_kiocb_to_cmd(req, struct io_rsrc_update);
551 if (unlikely(req->flags & (REQ_F_FIXED_FILE | REQ_F_BUFFER_SELECT)))
553 if (sqe->rw_flags || sqe->splice_fd_in)
556 up->offset = READ_ONCE(sqe->off);
557 up->nr_args = READ_ONCE(sqe->len);
560 up->arg = READ_ONCE(sqe->addr);
564 static int io_files_update_with_index_alloc(struct io_kiocb *req,
565 unsigned int issue_flags)
567 struct io_rsrc_update *up = io_kiocb_to_cmd(req, struct io_rsrc_update);
568 __s32 __user *fds = u64_to_user_ptr(up->arg);
573 if (!req->ctx->file_data)
576 for (done = 0; done < up->nr_args; done++) {
577 if (copy_from_user(&fd, &fds[done], sizeof(fd))) {
587 ret = io_fixed_fd_install(req, issue_flags, file,
588 IORING_FILE_INDEX_ALLOC);
591 if (copy_to_user(&fds[done], &ret, sizeof(ret))) {
592 __io_close_fixed(req->ctx, issue_flags, ret);
603 int io_files_update(struct io_kiocb *req, unsigned int issue_flags)
605 struct io_rsrc_update *up = io_kiocb_to_cmd(req, struct io_rsrc_update);
606 struct io_ring_ctx *ctx = req->ctx;
607 struct io_uring_rsrc_update2 up2;
610 up2.offset = up->offset;
617 if (up->offset == IORING_FILE_INDEX_ALLOC) {
618 ret = io_files_update_with_index_alloc(req, issue_flags);
620 io_ring_submit_lock(ctx, issue_flags);
621 ret = __io_register_rsrc_update(ctx, IORING_RSRC_FILE,
623 io_ring_submit_unlock(ctx, issue_flags);
628 io_req_set_res(req, ret, 0);
632 int io_queue_rsrc_removal(struct io_rsrc_data *data, unsigned idx, void *rsrc)
634 struct io_ring_ctx *ctx = data->ctx;
635 struct io_rsrc_node *node = ctx->rsrc_node;
636 u64 *tag_slot = io_get_tag_slot(data, idx);
638 ctx->rsrc_node = io_rsrc_node_alloc(ctx);
639 if (unlikely(!ctx->rsrc_node)) {
640 ctx->rsrc_node = node;
644 node->item.rsrc = rsrc;
645 node->item.tag = *tag_slot;
648 node->rsrc_data = data;
649 list_add_tail(&node->node, &ctx->rsrc_ref_list);
650 io_put_rsrc_node(ctx, node);
654 void __io_sqe_files_unregister(struct io_ring_ctx *ctx)
658 for (i = 0; i < ctx->nr_user_files; i++) {
659 struct file *file = io_file_from_index(&ctx->file_table, i);
661 /* skip scm accounted files, they'll be freed by ->ring_sock */
662 if (!file || io_file_need_scm(file))
664 io_file_bitmap_clear(&ctx->file_table, i);
668 #if defined(CONFIG_UNIX)
669 if (ctx->ring_sock) {
670 struct sock *sock = ctx->ring_sock->sk;
673 while ((skb = skb_dequeue(&sock->sk_receive_queue)) != NULL)
677 io_free_file_tables(&ctx->file_table);
678 io_file_table_set_alloc_range(ctx, 0, 0);
679 io_rsrc_data_free(ctx->file_data);
680 ctx->file_data = NULL;
681 ctx->nr_user_files = 0;
684 int io_sqe_files_unregister(struct io_ring_ctx *ctx)
686 unsigned nr = ctx->nr_user_files;
693 * Quiesce may unlock ->uring_lock, and while it's not held
694 * prevent new requests using the table.
696 ctx->nr_user_files = 0;
697 ret = io_rsrc_ref_quiesce(ctx->file_data, ctx);
698 ctx->nr_user_files = nr;
700 __io_sqe_files_unregister(ctx);
705 * Ensure the UNIX gc is aware of our file set, so we are certain that
706 * the io_uring can be safely unregistered on process exit, even if we have
707 * loops in the file referencing. We account only files that can hold other
708 * files because otherwise they can't form a loop and so are not interesting
711 int __io_scm_file_account(struct io_ring_ctx *ctx, struct file *file)
713 #if defined(CONFIG_UNIX)
714 struct sock *sk = ctx->ring_sock->sk;
715 struct sk_buff_head *head = &sk->sk_receive_queue;
716 struct scm_fp_list *fpl;
719 if (likely(!io_file_need_scm(file)))
723 * See if we can merge this file into an existing skb SCM_RIGHTS
724 * file set. If there's no room, fall back to allocating a new skb
727 spin_lock_irq(&head->lock);
728 skb = skb_peek(head);
729 if (skb && UNIXCB(skb).fp->count < SCM_MAX_FD)
730 __skb_unlink(skb, head);
733 spin_unlock_irq(&head->lock);
736 fpl = kzalloc(sizeof(*fpl), GFP_KERNEL);
740 skb = alloc_skb(0, GFP_KERNEL);
746 fpl->user = get_uid(current_user());
747 fpl->max = SCM_MAX_FD;
750 UNIXCB(skb).fp = fpl;
752 skb->scm_io_uring = 1;
753 skb->destructor = unix_destruct_scm;
754 refcount_add(skb->truesize, &sk->sk_wmem_alloc);
757 fpl = UNIXCB(skb).fp;
758 fpl->fp[fpl->count++] = get_file(file);
759 unix_inflight(fpl->user, file);
760 skb_queue_head(head, skb);
766 static __cold void io_rsrc_file_scm_put(struct io_ring_ctx *ctx, struct file *file)
768 #if defined(CONFIG_UNIX)
769 struct sock *sock = ctx->ring_sock->sk;
770 struct sk_buff_head list, *head = &sock->sk_receive_queue;
774 __skb_queue_head_init(&list);
777 * Find the skb that holds this file in its SCM_RIGHTS. When found,
778 * remove this entry and rearrange the file array.
780 skb = skb_dequeue(head);
782 struct scm_fp_list *fp;
785 for (i = 0; i < fp->count; i++) {
788 if (fp->fp[i] != file)
791 unix_notinflight(fp->user, fp->fp[i]);
792 left = fp->count - 1 - i;
794 memmove(&fp->fp[i], &fp->fp[i + 1],
795 left * sizeof(struct file *));
802 __skb_queue_tail(&list, skb);
812 __skb_queue_tail(&list, skb);
814 skb = skb_dequeue(head);
817 if (skb_peek(&list)) {
818 spin_lock_irq(&head->lock);
819 while ((skb = __skb_dequeue(&list)) != NULL)
820 __skb_queue_tail(head, skb);
821 spin_unlock_irq(&head->lock);
826 static void io_rsrc_file_put(struct io_ring_ctx *ctx, struct io_rsrc_put *prsrc)
828 struct file *file = prsrc->file;
830 if (likely(!io_file_need_scm(file)))
833 io_rsrc_file_scm_put(ctx, file);
836 int io_sqe_files_register(struct io_ring_ctx *ctx, void __user *arg,
837 unsigned nr_args, u64 __user *tags)
839 __s32 __user *fds = (__s32 __user *) arg;
848 if (nr_args > IORING_MAX_FIXED_FILES)
850 if (nr_args > rlimit(RLIMIT_NOFILE))
852 ret = io_rsrc_data_alloc(ctx, io_rsrc_file_put, tags, nr_args,
857 if (!io_alloc_file_tables(&ctx->file_table, nr_args)) {
858 io_rsrc_data_free(ctx->file_data);
859 ctx->file_data = NULL;
863 for (i = 0; i < nr_args; i++, ctx->nr_user_files++) {
864 struct io_fixed_file *file_slot;
866 if (fds && copy_from_user(&fd, &fds[i], sizeof(fd))) {
870 /* allow sparse sets */
871 if (!fds || fd == -1) {
873 if (unlikely(*io_get_tag_slot(ctx->file_data, i)))
884 * Don't allow io_uring instances to be registered. If UNIX
885 * isn't enabled, then this causes a reference cycle and this
886 * instance can never get freed. If UNIX is enabled we'll
887 * handle it just fine, but there's still no point in allowing
888 * a ring fd as it doesn't support regular read/write anyway.
890 if (io_is_uring_fops(file)) {
894 ret = io_scm_file_account(ctx, file);
899 file_slot = io_fixed_file_slot(&ctx->file_table, i);
900 io_fixed_file_set(file_slot, file);
901 io_file_bitmap_set(&ctx->file_table, i);
904 /* default it to the whole table */
905 io_file_table_set_alloc_range(ctx, 0, ctx->nr_user_files);
908 __io_sqe_files_unregister(ctx);
912 static void io_rsrc_buf_put(struct io_ring_ctx *ctx, struct io_rsrc_put *prsrc)
914 io_buffer_unmap(ctx, &prsrc->buf);
918 void __io_sqe_buffers_unregister(struct io_ring_ctx *ctx)
922 for (i = 0; i < ctx->nr_user_bufs; i++)
923 io_buffer_unmap(ctx, &ctx->user_bufs[i]);
924 kfree(ctx->user_bufs);
925 io_rsrc_data_free(ctx->buf_data);
926 ctx->user_bufs = NULL;
927 ctx->buf_data = NULL;
928 ctx->nr_user_bufs = 0;
931 int io_sqe_buffers_unregister(struct io_ring_ctx *ctx)
933 unsigned nr = ctx->nr_user_bufs;
940 * Quiesce may unlock ->uring_lock, and while it's not held
941 * prevent new requests using the table.
943 ctx->nr_user_bufs = 0;
944 ret = io_rsrc_ref_quiesce(ctx->buf_data, ctx);
945 ctx->nr_user_bufs = nr;
947 __io_sqe_buffers_unregister(ctx);
952 * Not super efficient, but this is just a registration time. And we do cache
953 * the last compound head, so generally we'll only do a full search if we don't
956 * We check if the given compound head page has already been accounted, to
957 * avoid double accounting it. This allows us to account the full size of the
958 * page, not just the constituent pages of a huge page.
960 static bool headpage_already_acct(struct io_ring_ctx *ctx, struct page **pages,
961 int nr_pages, struct page *hpage)
965 /* check current page array */
966 for (i = 0; i < nr_pages; i++) {
967 if (!PageCompound(pages[i]))
969 if (compound_head(pages[i]) == hpage)
973 /* check previously registered pages */
974 for (i = 0; i < ctx->nr_user_bufs; i++) {
975 struct io_mapped_ubuf *imu = ctx->user_bufs[i];
977 for (j = 0; j < imu->nr_bvecs; j++) {
978 if (!PageCompound(imu->bvec[j].bv_page))
980 if (compound_head(imu->bvec[j].bv_page) == hpage)
988 static int io_buffer_account_pin(struct io_ring_ctx *ctx, struct page **pages,
989 int nr_pages, struct io_mapped_ubuf *imu,
990 struct page **last_hpage)
995 for (i = 0; i < nr_pages; i++) {
996 if (!PageCompound(pages[i])) {
1001 hpage = compound_head(pages[i]);
1002 if (hpage == *last_hpage)
1004 *last_hpage = hpage;
1005 if (headpage_already_acct(ctx, pages, i, hpage))
1007 imu->acct_pages += page_size(hpage) >> PAGE_SHIFT;
1011 if (!imu->acct_pages)
1014 ret = io_account_mem(ctx, imu->acct_pages);
1016 imu->acct_pages = 0;
1020 struct page **io_pin_pages(unsigned long ubuf, unsigned long len, int *npages)
1022 unsigned long start, end, nr_pages;
1023 struct vm_area_struct **vmas = NULL;
1024 struct page **pages = NULL;
1025 int i, pret, ret = -ENOMEM;
1027 end = (ubuf + len + PAGE_SIZE - 1) >> PAGE_SHIFT;
1028 start = ubuf >> PAGE_SHIFT;
1029 nr_pages = end - start;
1031 pages = kvmalloc_array(nr_pages, sizeof(struct page *), GFP_KERNEL);
1035 vmas = kvmalloc_array(nr_pages, sizeof(struct vm_area_struct *),
1041 mmap_read_lock(current->mm);
1042 pret = pin_user_pages(ubuf, nr_pages, FOLL_WRITE | FOLL_LONGTERM,
1044 if (pret == nr_pages) {
1045 struct file *file = vmas[0]->vm_file;
1047 /* don't support file backed memory */
1048 for (i = 0; i < nr_pages; i++) {
1049 if (vmas[i]->vm_file != file) {
1055 if (!vma_is_shmem(vmas[i]) && !is_file_hugepages(file)) {
1062 ret = pret < 0 ? pret : -EFAULT;
1064 mmap_read_unlock(current->mm);
1067 * if we did partial map, or found file backed vmas,
1068 * release any pages we did get
1071 unpin_user_pages(pages, pret);
1079 pages = ERR_PTR(ret);
1084 static int io_sqe_buffer_register(struct io_ring_ctx *ctx, struct iovec *iov,
1085 struct io_mapped_ubuf **pimu,
1086 struct page **last_hpage)
1088 struct io_mapped_ubuf *imu = NULL;
1089 struct page **pages = NULL;
1092 int ret, nr_pages, i;
1093 struct folio *folio = NULL;
1095 *pimu = ctx->dummy_ubuf;
1100 pages = io_pin_pages((unsigned long) iov->iov_base, iov->iov_len,
1102 if (IS_ERR(pages)) {
1103 ret = PTR_ERR(pages);
1108 /* If it's a huge page, try to coalesce them into a single bvec entry */
1110 folio = page_folio(pages[0]);
1111 for (i = 1; i < nr_pages; i++) {
1112 if (page_folio(pages[i]) != folio) {
1119 * The pages are bound to the folio, it doesn't
1120 * actually unpin them but drops all but one reference,
1121 * which is usually put down by io_buffer_unmap().
1122 * Note, needs a better helper.
1124 unpin_user_pages(&pages[1], nr_pages - 1);
1129 imu = kvmalloc(struct_size(imu, bvec, nr_pages), GFP_KERNEL);
1133 ret = io_buffer_account_pin(ctx, pages, nr_pages, imu, last_hpage);
1135 unpin_user_pages(pages, nr_pages);
1139 off = (unsigned long) iov->iov_base & ~PAGE_MASK;
1140 size = iov->iov_len;
1141 /* store original address for later verification */
1142 imu->ubuf = (unsigned long) iov->iov_base;
1143 imu->ubuf_end = imu->ubuf + iov->iov_len;
1144 imu->nr_bvecs = nr_pages;
1149 bvec_set_page(&imu->bvec[0], pages[0], size, off);
1152 for (i = 0; i < nr_pages; i++) {
1155 vec_len = min_t(size_t, size, PAGE_SIZE - off);
1156 bvec_set_page(&imu->bvec[i], pages[i], vec_len, off);
1167 static int io_buffers_map_alloc(struct io_ring_ctx *ctx, unsigned int nr_args)
1169 ctx->user_bufs = kcalloc(nr_args, sizeof(*ctx->user_bufs), GFP_KERNEL);
1170 return ctx->user_bufs ? 0 : -ENOMEM;
1173 int io_sqe_buffers_register(struct io_ring_ctx *ctx, void __user *arg,
1174 unsigned int nr_args, u64 __user *tags)
1176 struct page *last_hpage = NULL;
1177 struct io_rsrc_data *data;
1181 BUILD_BUG_ON(IORING_MAX_REG_BUFFERS >= (1u << 16));
1185 if (!nr_args || nr_args > IORING_MAX_REG_BUFFERS)
1187 ret = io_rsrc_data_alloc(ctx, io_rsrc_buf_put, tags, nr_args, &data);
1190 ret = io_buffers_map_alloc(ctx, nr_args);
1192 io_rsrc_data_free(data);
1196 for (i = 0; i < nr_args; i++, ctx->nr_user_bufs++) {
1198 ret = io_copy_iov(ctx, &iov, arg, i);
1201 ret = io_buffer_validate(&iov);
1205 memset(&iov, 0, sizeof(iov));
1208 if (!iov.iov_base && *io_get_tag_slot(data, i)) {
1213 ret = io_sqe_buffer_register(ctx, &iov, &ctx->user_bufs[i],
1219 WARN_ON_ONCE(ctx->buf_data);
1221 ctx->buf_data = data;
1223 __io_sqe_buffers_unregister(ctx);
1227 int io_import_fixed(int ddir, struct iov_iter *iter,
1228 struct io_mapped_ubuf *imu,
1229 u64 buf_addr, size_t len)
1234 if (WARN_ON_ONCE(!imu))
1236 if (unlikely(check_add_overflow(buf_addr, (u64)len, &buf_end)))
1238 /* not inside the mapped region */
1239 if (unlikely(buf_addr < imu->ubuf || buf_end > imu->ubuf_end))
1243 * Might not be a start of buffer, set size appropriately
1244 * and advance us to the beginning.
1246 offset = buf_addr - imu->ubuf;
1247 iov_iter_bvec(iter, ddir, imu->bvec, imu->nr_bvecs, offset + len);
1251 * Don't use iov_iter_advance() here, as it's really slow for
1252 * using the latter parts of a big fixed buffer - it iterates
1253 * over each segment manually. We can cheat a bit here, because
1256 * 1) it's a BVEC iter, we set it up
1257 * 2) all bvecs are PAGE_SIZE in size, except potentially the
1258 * first and last bvec
1260 * So just find our index, and adjust the iterator afterwards.
1261 * If the offset is within the first bvec (or the whole first
1262 * bvec, just use iov_iter_advance(). This makes it easier
1263 * since we can just skip the first segment, which may not
1264 * be PAGE_SIZE aligned.
1266 const struct bio_vec *bvec = imu->bvec;
1268 if (offset <= bvec->bv_len) {
1270 * Note, huge pages buffers consists of one large
1271 * bvec entry and should always go this way. The other
1272 * branch doesn't expect non PAGE_SIZE'd chunks.
1275 iter->nr_segs = bvec->bv_len;
1276 iter->count -= offset;
1277 iter->iov_offset = offset;
1279 unsigned long seg_skip;
1281 /* skip first vec */
1282 offset -= bvec->bv_len;
1283 seg_skip = 1 + (offset >> PAGE_SHIFT);
1285 iter->bvec = bvec + seg_skip;
1286 iter->nr_segs -= seg_skip;
1287 iter->count -= bvec->bv_len + offset;
1288 iter->iov_offset = offset & ~PAGE_MASK;