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_one(struct io_rsrc_data *rsrc_data,
144 struct io_rsrc_put *prsrc)
146 struct io_ring_ctx *ctx = rsrc_data->ctx;
149 io_post_aux_cqe(ctx, prsrc->tag, 0, 0);
150 rsrc_data->do_put(ctx, prsrc);
153 static void __io_rsrc_put_work(struct io_rsrc_node *ref_node)
155 struct io_rsrc_data *rsrc_data = ref_node->rsrc_data;
157 if (likely(!ref_node->empty))
158 io_rsrc_put_work_one(rsrc_data, &ref_node->item);
160 io_rsrc_node_destroy(rsrc_data->ctx, ref_node);
163 void io_rsrc_node_destroy(struct io_ring_ctx *ctx, struct io_rsrc_node *node)
165 if (!io_alloc_cache_put(&ctx->rsrc_node_cache, &node->cache))
169 void io_rsrc_node_ref_zero(struct io_rsrc_node *node)
170 __must_hold(&node->rsrc_data->ctx->uring_lock)
172 struct io_ring_ctx *ctx = node->rsrc_data->ctx;
174 while (!list_empty(&ctx->rsrc_ref_list)) {
175 node = list_first_entry(&ctx->rsrc_ref_list,
176 struct io_rsrc_node, node);
177 /* recycle ref nodes in order */
180 list_del(&node->node);
181 __io_rsrc_put_work(node);
183 if (list_empty(&ctx->rsrc_ref_list) && unlikely(ctx->rsrc_quiesce))
184 wake_up_all(&ctx->rsrc_quiesce_wq);
187 struct io_rsrc_node *io_rsrc_node_alloc(struct io_ring_ctx *ctx)
189 struct io_rsrc_node *ref_node;
190 struct io_cache_entry *entry;
192 entry = io_alloc_cache_get(&ctx->rsrc_node_cache);
194 ref_node = container_of(entry, struct io_rsrc_node, cache);
196 ref_node = kzalloc(sizeof(*ref_node), GFP_KERNEL);
201 ref_node->rsrc_data = NULL;
207 __cold static int io_rsrc_ref_quiesce(struct io_rsrc_data *data,
208 struct io_ring_ctx *ctx)
210 struct io_rsrc_node *backup;
214 /* As We may drop ->uring_lock, other task may have started quiesce */
218 backup = io_rsrc_node_alloc(ctx);
221 ctx->rsrc_node->empty = true;
222 ctx->rsrc_node->rsrc_data = data;
223 list_add_tail(&ctx->rsrc_node->node, &ctx->rsrc_ref_list);
224 io_put_rsrc_node(ctx, ctx->rsrc_node);
225 ctx->rsrc_node = backup;
227 if (list_empty(&ctx->rsrc_ref_list))
230 if (ctx->flags & IORING_SETUP_DEFER_TASKRUN) {
231 atomic_set(&ctx->cq_wait_nr, 1);
236 data->quiesce = true;
238 prepare_to_wait(&ctx->rsrc_quiesce_wq, &we, TASK_INTERRUPTIBLE);
239 mutex_unlock(&ctx->uring_lock);
241 ret = io_run_task_work_sig(ctx);
243 mutex_lock(&ctx->uring_lock);
244 if (list_empty(&ctx->rsrc_ref_list))
250 __set_current_state(TASK_RUNNING);
251 mutex_lock(&ctx->uring_lock);
253 } while (!list_empty(&ctx->rsrc_ref_list));
255 finish_wait(&ctx->rsrc_quiesce_wq, &we);
256 data->quiesce = false;
259 if (ctx->flags & IORING_SETUP_DEFER_TASKRUN) {
260 atomic_set(&ctx->cq_wait_nr, 0);
266 static void io_free_page_table(void **table, size_t size)
268 unsigned i, nr_tables = DIV_ROUND_UP(size, PAGE_SIZE);
270 for (i = 0; i < nr_tables; i++)
275 static void io_rsrc_data_free(struct io_rsrc_data *data)
277 size_t size = data->nr * sizeof(data->tags[0][0]);
280 io_free_page_table((void **)data->tags, size);
284 static __cold void **io_alloc_page_table(size_t size)
286 unsigned i, nr_tables = DIV_ROUND_UP(size, PAGE_SIZE);
287 size_t init_size = size;
290 table = kcalloc(nr_tables, sizeof(*table), GFP_KERNEL_ACCOUNT);
294 for (i = 0; i < nr_tables; i++) {
295 unsigned int this_size = min_t(size_t, size, PAGE_SIZE);
297 table[i] = kzalloc(this_size, GFP_KERNEL_ACCOUNT);
299 io_free_page_table(table, init_size);
307 __cold static int io_rsrc_data_alloc(struct io_ring_ctx *ctx,
308 rsrc_put_fn *do_put, u64 __user *utags,
309 unsigned nr, struct io_rsrc_data **pdata)
311 struct io_rsrc_data *data;
315 data = kzalloc(sizeof(*data), GFP_KERNEL);
318 data->tags = (u64 **)io_alloc_page_table(nr * sizeof(data->tags[0][0]));
326 data->do_put = do_put;
329 for (i = 0; i < nr; i++) {
330 u64 *tag_slot = io_get_tag_slot(data, i);
332 if (copy_from_user(tag_slot, &utags[i],
340 io_rsrc_data_free(data);
344 static int __io_sqe_files_update(struct io_ring_ctx *ctx,
345 struct io_uring_rsrc_update2 *up,
348 u64 __user *tags = u64_to_user_ptr(up->tags);
349 __s32 __user *fds = u64_to_user_ptr(up->data);
350 struct io_rsrc_data *data = ctx->file_data;
351 struct io_fixed_file *file_slot;
358 if (up->offset + nr_args > ctx->nr_user_files)
361 for (done = 0; done < nr_args; done++) {
364 if ((tags && copy_from_user(&tag, &tags[done], sizeof(tag))) ||
365 copy_from_user(&fd, &fds[done], sizeof(fd))) {
369 if ((fd == IORING_REGISTER_FILES_SKIP || fd == -1) && tag) {
373 if (fd == IORING_REGISTER_FILES_SKIP)
376 i = array_index_nospec(up->offset + done, ctx->nr_user_files);
377 file_slot = io_fixed_file_slot(&ctx->file_table, i);
379 if (file_slot->file_ptr) {
380 file = (struct file *)(file_slot->file_ptr & FFS_MASK);
381 err = io_queue_rsrc_removal(data, i, file);
384 file_slot->file_ptr = 0;
385 io_file_bitmap_clear(&ctx->file_table, i);
394 * Don't allow io_uring instances to be registered. If
395 * UNIX isn't enabled, then this causes a reference
396 * cycle and this instance can never get freed. If UNIX
397 * is enabled we'll handle it just fine, but there's
398 * still no point in allowing a ring fd as it doesn't
399 * support regular read/write anyway.
401 if (io_is_uring_fops(file)) {
406 err = io_scm_file_account(ctx, file);
411 *io_get_tag_slot(data, i) = tag;
412 io_fixed_file_set(file_slot, file);
413 io_file_bitmap_set(&ctx->file_table, i);
416 return done ? done : err;
419 static int __io_sqe_buffers_update(struct io_ring_ctx *ctx,
420 struct io_uring_rsrc_update2 *up,
421 unsigned int nr_args)
423 u64 __user *tags = u64_to_user_ptr(up->tags);
424 struct iovec iov, __user *iovs = u64_to_user_ptr(up->data);
425 struct page *last_hpage = NULL;
431 if (up->offset + nr_args > ctx->nr_user_bufs)
434 for (done = 0; done < nr_args; done++) {
435 struct io_mapped_ubuf *imu;
438 err = io_copy_iov(ctx, &iov, iovs, done);
441 if (tags && copy_from_user(&tag, &tags[done], sizeof(tag))) {
445 err = io_buffer_validate(&iov);
448 if (!iov.iov_base && tag) {
452 err = io_sqe_buffer_register(ctx, &iov, &imu, &last_hpage);
456 i = array_index_nospec(up->offset + done, ctx->nr_user_bufs);
457 if (ctx->user_bufs[i] != ctx->dummy_ubuf) {
458 err = io_queue_rsrc_removal(ctx->buf_data, i,
461 io_buffer_unmap(ctx, &imu);
464 ctx->user_bufs[i] = ctx->dummy_ubuf;
467 ctx->user_bufs[i] = imu;
468 *io_get_tag_slot(ctx->buf_data, i) = tag;
470 return done ? done : err;
473 static int __io_register_rsrc_update(struct io_ring_ctx *ctx, unsigned type,
474 struct io_uring_rsrc_update2 *up,
479 lockdep_assert_held(&ctx->uring_lock);
481 if (check_add_overflow(up->offset, nr_args, &tmp))
485 case IORING_RSRC_FILE:
486 return __io_sqe_files_update(ctx, up, nr_args);
487 case IORING_RSRC_BUFFER:
488 return __io_sqe_buffers_update(ctx, up, nr_args);
493 int io_register_files_update(struct io_ring_ctx *ctx, void __user *arg,
496 struct io_uring_rsrc_update2 up;
500 memset(&up, 0, sizeof(up));
501 if (copy_from_user(&up, arg, sizeof(struct io_uring_rsrc_update)))
503 if (up.resv || up.resv2)
505 return __io_register_rsrc_update(ctx, IORING_RSRC_FILE, &up, nr_args);
508 int io_register_rsrc_update(struct io_ring_ctx *ctx, void __user *arg,
509 unsigned size, unsigned type)
511 struct io_uring_rsrc_update2 up;
513 if (size != sizeof(up))
515 if (copy_from_user(&up, arg, sizeof(up)))
517 if (!up.nr || up.resv || up.resv2)
519 return __io_register_rsrc_update(ctx, type, &up, up.nr);
522 __cold int io_register_rsrc(struct io_ring_ctx *ctx, void __user *arg,
523 unsigned int size, unsigned int type)
525 struct io_uring_rsrc_register rr;
527 /* keep it extendible */
528 if (size != sizeof(rr))
531 memset(&rr, 0, sizeof(rr));
532 if (copy_from_user(&rr, arg, size))
534 if (!rr.nr || rr.resv2)
536 if (rr.flags & ~IORING_RSRC_REGISTER_SPARSE)
540 case IORING_RSRC_FILE:
541 if (rr.flags & IORING_RSRC_REGISTER_SPARSE && rr.data)
543 return io_sqe_files_register(ctx, u64_to_user_ptr(rr.data),
544 rr.nr, u64_to_user_ptr(rr.tags));
545 case IORING_RSRC_BUFFER:
546 if (rr.flags & IORING_RSRC_REGISTER_SPARSE && rr.data)
548 return io_sqe_buffers_register(ctx, u64_to_user_ptr(rr.data),
549 rr.nr, u64_to_user_ptr(rr.tags));
554 int io_files_update_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
556 struct io_rsrc_update *up = io_kiocb_to_cmd(req, struct io_rsrc_update);
558 if (unlikely(req->flags & (REQ_F_FIXED_FILE | REQ_F_BUFFER_SELECT)))
560 if (sqe->rw_flags || sqe->splice_fd_in)
563 up->offset = READ_ONCE(sqe->off);
564 up->nr_args = READ_ONCE(sqe->len);
567 up->arg = READ_ONCE(sqe->addr);
571 static int io_files_update_with_index_alloc(struct io_kiocb *req,
572 unsigned int issue_flags)
574 struct io_rsrc_update *up = io_kiocb_to_cmd(req, struct io_rsrc_update);
575 __s32 __user *fds = u64_to_user_ptr(up->arg);
580 if (!req->ctx->file_data)
583 for (done = 0; done < up->nr_args; done++) {
584 if (copy_from_user(&fd, &fds[done], sizeof(fd))) {
594 ret = io_fixed_fd_install(req, issue_flags, file,
595 IORING_FILE_INDEX_ALLOC);
598 if (copy_to_user(&fds[done], &ret, sizeof(ret))) {
599 __io_close_fixed(req->ctx, issue_flags, ret);
610 int io_files_update(struct io_kiocb *req, unsigned int issue_flags)
612 struct io_rsrc_update *up = io_kiocb_to_cmd(req, struct io_rsrc_update);
613 struct io_ring_ctx *ctx = req->ctx;
614 struct io_uring_rsrc_update2 up2;
617 up2.offset = up->offset;
624 if (up->offset == IORING_FILE_INDEX_ALLOC) {
625 ret = io_files_update_with_index_alloc(req, issue_flags);
627 io_ring_submit_lock(ctx, issue_flags);
628 ret = __io_register_rsrc_update(ctx, IORING_RSRC_FILE,
630 io_ring_submit_unlock(ctx, issue_flags);
635 io_req_set_res(req, ret, 0);
639 int io_queue_rsrc_removal(struct io_rsrc_data *data, unsigned idx, void *rsrc)
641 struct io_ring_ctx *ctx = data->ctx;
642 struct io_rsrc_node *node = ctx->rsrc_node;
643 u64 *tag_slot = io_get_tag_slot(data, idx);
645 ctx->rsrc_node = io_rsrc_node_alloc(ctx);
646 if (unlikely(!ctx->rsrc_node)) {
647 ctx->rsrc_node = node;
651 node->item.rsrc = rsrc;
652 node->item.tag = *tag_slot;
655 node->rsrc_data = data;
656 list_add_tail(&node->node, &ctx->rsrc_ref_list);
657 io_put_rsrc_node(ctx, node);
661 void __io_sqe_files_unregister(struct io_ring_ctx *ctx)
665 for (i = 0; i < ctx->nr_user_files; i++) {
666 struct file *file = io_file_from_index(&ctx->file_table, i);
668 /* skip scm accounted files, they'll be freed by ->ring_sock */
669 if (!file || io_file_need_scm(file))
671 io_file_bitmap_clear(&ctx->file_table, i);
675 #if defined(CONFIG_UNIX)
676 if (ctx->ring_sock) {
677 struct sock *sock = ctx->ring_sock->sk;
680 while ((skb = skb_dequeue(&sock->sk_receive_queue)) != NULL)
684 io_free_file_tables(&ctx->file_table);
685 io_file_table_set_alloc_range(ctx, 0, 0);
686 io_rsrc_data_free(ctx->file_data);
687 ctx->file_data = NULL;
688 ctx->nr_user_files = 0;
691 int io_sqe_files_unregister(struct io_ring_ctx *ctx)
693 unsigned nr = ctx->nr_user_files;
700 * Quiesce may unlock ->uring_lock, and while it's not held
701 * prevent new requests using the table.
703 ctx->nr_user_files = 0;
704 ret = io_rsrc_ref_quiesce(ctx->file_data, ctx);
705 ctx->nr_user_files = nr;
707 __io_sqe_files_unregister(ctx);
712 * Ensure the UNIX gc is aware of our file set, so we are certain that
713 * the io_uring can be safely unregistered on process exit, even if we have
714 * loops in the file referencing. We account only files that can hold other
715 * files because otherwise they can't form a loop and so are not interesting
718 int __io_scm_file_account(struct io_ring_ctx *ctx, struct file *file)
720 #if defined(CONFIG_UNIX)
721 struct sock *sk = ctx->ring_sock->sk;
722 struct sk_buff_head *head = &sk->sk_receive_queue;
723 struct scm_fp_list *fpl;
726 if (likely(!io_file_need_scm(file)))
730 * See if we can merge this file into an existing skb SCM_RIGHTS
731 * file set. If there's no room, fall back to allocating a new skb
734 spin_lock_irq(&head->lock);
735 skb = skb_peek(head);
736 if (skb && UNIXCB(skb).fp->count < SCM_MAX_FD)
737 __skb_unlink(skb, head);
740 spin_unlock_irq(&head->lock);
743 fpl = kzalloc(sizeof(*fpl), GFP_KERNEL);
747 skb = alloc_skb(0, GFP_KERNEL);
753 fpl->user = get_uid(current_user());
754 fpl->max = SCM_MAX_FD;
757 UNIXCB(skb).fp = fpl;
759 skb->scm_io_uring = 1;
760 skb->destructor = unix_destruct_scm;
761 refcount_add(skb->truesize, &sk->sk_wmem_alloc);
764 fpl = UNIXCB(skb).fp;
765 fpl->fp[fpl->count++] = get_file(file);
766 unix_inflight(fpl->user, file);
767 skb_queue_head(head, skb);
773 static __cold void io_rsrc_file_scm_put(struct io_ring_ctx *ctx, struct file *file)
775 #if defined(CONFIG_UNIX)
776 struct sock *sock = ctx->ring_sock->sk;
777 struct sk_buff_head list, *head = &sock->sk_receive_queue;
781 __skb_queue_head_init(&list);
784 * Find the skb that holds this file in its SCM_RIGHTS. When found,
785 * remove this entry and rearrange the file array.
787 skb = skb_dequeue(head);
789 struct scm_fp_list *fp;
792 for (i = 0; i < fp->count; i++) {
795 if (fp->fp[i] != file)
798 unix_notinflight(fp->user, fp->fp[i]);
799 left = fp->count - 1 - i;
801 memmove(&fp->fp[i], &fp->fp[i + 1],
802 left * sizeof(struct file *));
809 __skb_queue_tail(&list, skb);
819 __skb_queue_tail(&list, skb);
821 skb = skb_dequeue(head);
824 if (skb_peek(&list)) {
825 spin_lock_irq(&head->lock);
826 while ((skb = __skb_dequeue(&list)) != NULL)
827 __skb_queue_tail(head, skb);
828 spin_unlock_irq(&head->lock);
833 static void io_rsrc_file_put(struct io_ring_ctx *ctx, struct io_rsrc_put *prsrc)
835 struct file *file = prsrc->file;
837 if (likely(!io_file_need_scm(file)))
840 io_rsrc_file_scm_put(ctx, file);
843 int io_sqe_files_register(struct io_ring_ctx *ctx, void __user *arg,
844 unsigned nr_args, u64 __user *tags)
846 __s32 __user *fds = (__s32 __user *) arg;
855 if (nr_args > IORING_MAX_FIXED_FILES)
857 if (nr_args > rlimit(RLIMIT_NOFILE))
859 ret = io_rsrc_data_alloc(ctx, io_rsrc_file_put, tags, nr_args,
864 if (!io_alloc_file_tables(&ctx->file_table, nr_args)) {
865 io_rsrc_data_free(ctx->file_data);
866 ctx->file_data = NULL;
870 for (i = 0; i < nr_args; i++, ctx->nr_user_files++) {
871 struct io_fixed_file *file_slot;
873 if (fds && copy_from_user(&fd, &fds[i], sizeof(fd))) {
877 /* allow sparse sets */
878 if (!fds || fd == -1) {
880 if (unlikely(*io_get_tag_slot(ctx->file_data, i)))
891 * Don't allow io_uring instances to be registered. If UNIX
892 * isn't enabled, then this causes a reference cycle and this
893 * instance can never get freed. If UNIX is enabled we'll
894 * handle it just fine, but there's still no point in allowing
895 * a ring fd as it doesn't support regular read/write anyway.
897 if (io_is_uring_fops(file)) {
901 ret = io_scm_file_account(ctx, file);
906 file_slot = io_fixed_file_slot(&ctx->file_table, i);
907 io_fixed_file_set(file_slot, file);
908 io_file_bitmap_set(&ctx->file_table, i);
911 /* default it to the whole table */
912 io_file_table_set_alloc_range(ctx, 0, ctx->nr_user_files);
915 __io_sqe_files_unregister(ctx);
919 static void io_rsrc_buf_put(struct io_ring_ctx *ctx, struct io_rsrc_put *prsrc)
921 io_buffer_unmap(ctx, &prsrc->buf);
925 void __io_sqe_buffers_unregister(struct io_ring_ctx *ctx)
929 for (i = 0; i < ctx->nr_user_bufs; i++)
930 io_buffer_unmap(ctx, &ctx->user_bufs[i]);
931 kfree(ctx->user_bufs);
932 io_rsrc_data_free(ctx->buf_data);
933 ctx->user_bufs = NULL;
934 ctx->buf_data = NULL;
935 ctx->nr_user_bufs = 0;
938 int io_sqe_buffers_unregister(struct io_ring_ctx *ctx)
940 unsigned nr = ctx->nr_user_bufs;
947 * Quiesce may unlock ->uring_lock, and while it's not held
948 * prevent new requests using the table.
950 ctx->nr_user_bufs = 0;
951 ret = io_rsrc_ref_quiesce(ctx->buf_data, ctx);
952 ctx->nr_user_bufs = nr;
954 __io_sqe_buffers_unregister(ctx);
959 * Not super efficient, but this is just a registration time. And we do cache
960 * the last compound head, so generally we'll only do a full search if we don't
963 * We check if the given compound head page has already been accounted, to
964 * avoid double accounting it. This allows us to account the full size of the
965 * page, not just the constituent pages of a huge page.
967 static bool headpage_already_acct(struct io_ring_ctx *ctx, struct page **pages,
968 int nr_pages, struct page *hpage)
972 /* check current page array */
973 for (i = 0; i < nr_pages; i++) {
974 if (!PageCompound(pages[i]))
976 if (compound_head(pages[i]) == hpage)
980 /* check previously registered pages */
981 for (i = 0; i < ctx->nr_user_bufs; i++) {
982 struct io_mapped_ubuf *imu = ctx->user_bufs[i];
984 for (j = 0; j < imu->nr_bvecs; j++) {
985 if (!PageCompound(imu->bvec[j].bv_page))
987 if (compound_head(imu->bvec[j].bv_page) == hpage)
995 static int io_buffer_account_pin(struct io_ring_ctx *ctx, struct page **pages,
996 int nr_pages, struct io_mapped_ubuf *imu,
997 struct page **last_hpage)
1001 imu->acct_pages = 0;
1002 for (i = 0; i < nr_pages; i++) {
1003 if (!PageCompound(pages[i])) {
1008 hpage = compound_head(pages[i]);
1009 if (hpage == *last_hpage)
1011 *last_hpage = hpage;
1012 if (headpage_already_acct(ctx, pages, i, hpage))
1014 imu->acct_pages += page_size(hpage) >> PAGE_SHIFT;
1018 if (!imu->acct_pages)
1021 ret = io_account_mem(ctx, imu->acct_pages);
1023 imu->acct_pages = 0;
1027 struct page **io_pin_pages(unsigned long ubuf, unsigned long len, int *npages)
1029 unsigned long start, end, nr_pages;
1030 struct vm_area_struct **vmas = NULL;
1031 struct page **pages = NULL;
1032 int i, pret, ret = -ENOMEM;
1034 end = (ubuf + len + PAGE_SIZE - 1) >> PAGE_SHIFT;
1035 start = ubuf >> PAGE_SHIFT;
1036 nr_pages = end - start;
1038 pages = kvmalloc_array(nr_pages, sizeof(struct page *), GFP_KERNEL);
1042 vmas = kvmalloc_array(nr_pages, sizeof(struct vm_area_struct *),
1048 mmap_read_lock(current->mm);
1049 pret = pin_user_pages(ubuf, nr_pages, FOLL_WRITE | FOLL_LONGTERM,
1051 if (pret == nr_pages) {
1052 struct file *file = vmas[0]->vm_file;
1054 /* don't support file backed memory */
1055 for (i = 0; i < nr_pages; i++) {
1056 if (vmas[i]->vm_file != file) {
1062 if (!vma_is_shmem(vmas[i]) && !is_file_hugepages(file)) {
1069 ret = pret < 0 ? pret : -EFAULT;
1071 mmap_read_unlock(current->mm);
1074 * if we did partial map, or found file backed vmas,
1075 * release any pages we did get
1078 unpin_user_pages(pages, pret);
1086 pages = ERR_PTR(ret);
1091 static int io_sqe_buffer_register(struct io_ring_ctx *ctx, struct iovec *iov,
1092 struct io_mapped_ubuf **pimu,
1093 struct page **last_hpage)
1095 struct io_mapped_ubuf *imu = NULL;
1096 struct page **pages = NULL;
1099 int ret, nr_pages, i;
1100 struct folio *folio = NULL;
1102 *pimu = ctx->dummy_ubuf;
1107 pages = io_pin_pages((unsigned long) iov->iov_base, iov->iov_len,
1109 if (IS_ERR(pages)) {
1110 ret = PTR_ERR(pages);
1115 /* If it's a huge page, try to coalesce them into a single bvec entry */
1117 folio = page_folio(pages[0]);
1118 for (i = 1; i < nr_pages; i++) {
1119 if (page_folio(pages[i]) != folio) {
1126 * The pages are bound to the folio, it doesn't
1127 * actually unpin them but drops all but one reference,
1128 * which is usually put down by io_buffer_unmap().
1129 * Note, needs a better helper.
1131 unpin_user_pages(&pages[1], nr_pages - 1);
1136 imu = kvmalloc(struct_size(imu, bvec, nr_pages), GFP_KERNEL);
1140 ret = io_buffer_account_pin(ctx, pages, nr_pages, imu, last_hpage);
1142 unpin_user_pages(pages, nr_pages);
1146 off = (unsigned long) iov->iov_base & ~PAGE_MASK;
1147 size = iov->iov_len;
1148 /* store original address for later verification */
1149 imu->ubuf = (unsigned long) iov->iov_base;
1150 imu->ubuf_end = imu->ubuf + iov->iov_len;
1151 imu->nr_bvecs = nr_pages;
1156 bvec_set_page(&imu->bvec[0], pages[0], size, off);
1159 for (i = 0; i < nr_pages; i++) {
1162 vec_len = min_t(size_t, size, PAGE_SIZE - off);
1163 bvec_set_page(&imu->bvec[i], pages[i], vec_len, off);
1174 static int io_buffers_map_alloc(struct io_ring_ctx *ctx, unsigned int nr_args)
1176 ctx->user_bufs = kcalloc(nr_args, sizeof(*ctx->user_bufs), GFP_KERNEL);
1177 return ctx->user_bufs ? 0 : -ENOMEM;
1180 int io_sqe_buffers_register(struct io_ring_ctx *ctx, void __user *arg,
1181 unsigned int nr_args, u64 __user *tags)
1183 struct page *last_hpage = NULL;
1184 struct io_rsrc_data *data;
1188 BUILD_BUG_ON(IORING_MAX_REG_BUFFERS >= (1u << 16));
1192 if (!nr_args || nr_args > IORING_MAX_REG_BUFFERS)
1194 ret = io_rsrc_data_alloc(ctx, io_rsrc_buf_put, tags, nr_args, &data);
1197 ret = io_buffers_map_alloc(ctx, nr_args);
1199 io_rsrc_data_free(data);
1203 for (i = 0; i < nr_args; i++, ctx->nr_user_bufs++) {
1205 ret = io_copy_iov(ctx, &iov, arg, i);
1208 ret = io_buffer_validate(&iov);
1212 memset(&iov, 0, sizeof(iov));
1215 if (!iov.iov_base && *io_get_tag_slot(data, i)) {
1220 ret = io_sqe_buffer_register(ctx, &iov, &ctx->user_bufs[i],
1226 WARN_ON_ONCE(ctx->buf_data);
1228 ctx->buf_data = data;
1230 __io_sqe_buffers_unregister(ctx);
1234 int io_import_fixed(int ddir, struct iov_iter *iter,
1235 struct io_mapped_ubuf *imu,
1236 u64 buf_addr, size_t len)
1241 if (WARN_ON_ONCE(!imu))
1243 if (unlikely(check_add_overflow(buf_addr, (u64)len, &buf_end)))
1245 /* not inside the mapped region */
1246 if (unlikely(buf_addr < imu->ubuf || buf_end > imu->ubuf_end))
1250 * Might not be a start of buffer, set size appropriately
1251 * and advance us to the beginning.
1253 offset = buf_addr - imu->ubuf;
1254 iov_iter_bvec(iter, ddir, imu->bvec, imu->nr_bvecs, offset + len);
1258 * Don't use iov_iter_advance() here, as it's really slow for
1259 * using the latter parts of a big fixed buffer - it iterates
1260 * over each segment manually. We can cheat a bit here, because
1263 * 1) it's a BVEC iter, we set it up
1264 * 2) all bvecs are PAGE_SIZE in size, except potentially the
1265 * first and last bvec
1267 * So just find our index, and adjust the iterator afterwards.
1268 * If the offset is within the first bvec (or the whole first
1269 * bvec, just use iov_iter_advance(). This makes it easier
1270 * since we can just skip the first segment, which may not
1271 * be PAGE_SIZE aligned.
1273 const struct bio_vec *bvec = imu->bvec;
1275 if (offset <= bvec->bv_len) {
1277 * Note, huge pages buffers consists of one large
1278 * bvec entry and should always go this way. The other
1279 * branch doesn't expect non PAGE_SIZE'd chunks.
1282 iter->nr_segs = bvec->bv_len;
1283 iter->count -= offset;
1284 iter->iov_offset = offset;
1286 unsigned long seg_skip;
1288 /* skip first vec */
1289 offset -= bvec->bv_len;
1290 seg_skip = 1 + (offset >> PAGE_SHIFT);
1292 iter->bvec = bvec + seg_skip;
1293 iter->nr_segs -= seg_skip;
1294 iter->count -= bvec->bv_len + offset;
1295 iter->iov_offset = offset & ~PAGE_MASK;