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 static inline bool io_put_rsrc_data_ref(struct io_rsrc_data *rsrc_data)
36 return !--rsrc_data->refs;
39 int __io_account_mem(struct user_struct *user, unsigned long nr_pages)
41 unsigned long page_limit, cur_pages, new_pages;
46 /* Don't allow more pages than we can safely lock */
47 page_limit = rlimit(RLIMIT_MEMLOCK) >> PAGE_SHIFT;
49 cur_pages = atomic_long_read(&user->locked_vm);
51 new_pages = cur_pages + nr_pages;
52 if (new_pages > page_limit)
54 } while (!atomic_long_try_cmpxchg(&user->locked_vm,
55 &cur_pages, new_pages));
59 static void io_unaccount_mem(struct io_ring_ctx *ctx, unsigned long nr_pages)
62 __io_unaccount_mem(ctx->user, nr_pages);
65 atomic64_sub(nr_pages, &ctx->mm_account->pinned_vm);
68 static int io_account_mem(struct io_ring_ctx *ctx, unsigned long nr_pages)
73 ret = __io_account_mem(ctx->user, nr_pages);
79 atomic64_add(nr_pages, &ctx->mm_account->pinned_vm);
84 static int io_copy_iov(struct io_ring_ctx *ctx, struct iovec *dst,
85 void __user *arg, unsigned index)
87 struct iovec __user *src;
91 struct compat_iovec __user *ciovs;
92 struct compat_iovec ciov;
94 ciovs = (struct compat_iovec __user *) arg;
95 if (copy_from_user(&ciov, &ciovs[index], sizeof(ciov)))
98 dst->iov_base = u64_to_user_ptr((u64)ciov.iov_base);
99 dst->iov_len = ciov.iov_len;
103 src = (struct iovec __user *) arg;
104 if (copy_from_user(dst, &src[index], sizeof(*dst)))
109 static int io_buffer_validate(struct iovec *iov)
111 unsigned long tmp, acct_len = iov->iov_len + (PAGE_SIZE - 1);
114 * Don't impose further limits on the size and buffer
115 * constraints here, we'll -EINVAL later when IO is
116 * submitted if they are wrong.
119 return iov->iov_len ? -EFAULT : 0;
123 /* arbitrary limit, but we need something */
124 if (iov->iov_len > SZ_1G)
127 if (check_add_overflow((unsigned long)iov->iov_base, acct_len, &tmp))
133 static void io_buffer_unmap(struct io_ring_ctx *ctx, struct io_mapped_ubuf **slot)
135 struct io_mapped_ubuf *imu = *slot;
138 if (imu != ctx->dummy_ubuf) {
139 for (i = 0; i < imu->nr_bvecs; i++)
140 unpin_user_page(imu->bvec[i].bv_page);
142 io_unaccount_mem(ctx, imu->acct_pages);
148 static void io_rsrc_put_work_one(struct io_rsrc_data *rsrc_data,
149 struct io_rsrc_put *prsrc)
151 struct io_ring_ctx *ctx = rsrc_data->ctx;
154 io_post_aux_cqe(ctx, prsrc->tag, 0, 0);
155 rsrc_data->do_put(ctx, prsrc);
158 static void __io_rsrc_put_work(struct io_rsrc_node *ref_node)
160 struct io_rsrc_data *rsrc_data = ref_node->rsrc_data;
161 struct io_rsrc_put *prsrc, *tmp;
163 if (ref_node->inline_items)
164 io_rsrc_put_work_one(rsrc_data, &ref_node->item);
166 list_for_each_entry_safe(prsrc, tmp, &ref_node->item_list, list) {
167 list_del(&prsrc->list);
168 io_rsrc_put_work_one(rsrc_data, prsrc);
172 io_rsrc_node_destroy(rsrc_data->ctx, ref_node);
173 if (io_put_rsrc_data_ref(rsrc_data))
174 complete(&rsrc_data->done);
177 void io_wait_rsrc_data(struct io_rsrc_data *data)
179 if (data && !io_put_rsrc_data_ref(data))
180 wait_for_completion(&data->done);
183 void io_rsrc_node_destroy(struct io_ring_ctx *ctx, struct io_rsrc_node *node)
185 if (!io_alloc_cache_put(&ctx->rsrc_node_cache, &node->cache))
189 void io_rsrc_node_ref_zero(struct io_rsrc_node *node)
190 __must_hold(&node->rsrc_data->ctx->uring_lock)
192 struct io_ring_ctx *ctx = node->rsrc_data->ctx;
195 while (!list_empty(&ctx->rsrc_ref_list)) {
196 node = list_first_entry(&ctx->rsrc_ref_list,
197 struct io_rsrc_node, node);
198 /* recycle ref nodes in order */
202 list_del(&node->node);
203 __io_rsrc_put_work(node);
207 static struct io_rsrc_node *io_rsrc_node_alloc(struct io_ring_ctx *ctx)
209 struct io_rsrc_node *ref_node;
210 struct io_cache_entry *entry;
212 entry = io_alloc_cache_get(&ctx->rsrc_node_cache);
214 ref_node = container_of(entry, struct io_rsrc_node, cache);
216 ref_node = kzalloc(sizeof(*ref_node), GFP_KERNEL);
222 INIT_LIST_HEAD(&ref_node->node);
223 INIT_LIST_HEAD(&ref_node->item_list);
224 ref_node->done = false;
225 ref_node->inline_items = 0;
229 void io_rsrc_node_switch(struct io_ring_ctx *ctx,
230 struct io_rsrc_data *data_to_kill)
231 __must_hold(&ctx->uring_lock)
233 WARN_ON_ONCE(!ctx->rsrc_backup_node);
234 WARN_ON_ONCE(data_to_kill && !ctx->rsrc_node);
237 struct io_rsrc_node *rsrc_node = ctx->rsrc_node;
239 rsrc_node->rsrc_data = data_to_kill;
240 list_add_tail(&rsrc_node->node, &ctx->rsrc_ref_list);
242 data_to_kill->refs++;
244 io_put_rsrc_node(ctx, rsrc_node);
245 ctx->rsrc_node = NULL;
248 if (!ctx->rsrc_node) {
249 ctx->rsrc_node = ctx->rsrc_backup_node;
250 ctx->rsrc_backup_node = NULL;
254 int io_rsrc_node_switch_start(struct io_ring_ctx *ctx)
256 if (ctx->rsrc_backup_node)
258 ctx->rsrc_backup_node = io_rsrc_node_alloc(ctx);
259 return ctx->rsrc_backup_node ? 0 : -ENOMEM;
262 __cold static int io_rsrc_ref_quiesce(struct io_rsrc_data *data,
263 struct io_ring_ctx *ctx)
267 /* As we may drop ->uring_lock, other task may have started quiesce */
270 ret = io_rsrc_node_switch_start(ctx);
273 io_rsrc_node_switch(ctx, data);
275 /* kill initial ref */
276 if (io_put_rsrc_data_ref(data))
279 data->quiesce = true;
280 mutex_unlock(&ctx->uring_lock);
282 ret = io_run_task_work_sig(ctx);
284 mutex_lock(&ctx->uring_lock);
288 /* restore the master reference */
293 ret = wait_for_completion_interruptible(&data->done);
295 mutex_lock(&ctx->uring_lock);
299 * it has been revived by another thread while
302 mutex_unlock(&ctx->uring_lock);
305 data->quiesce = false;
310 static void io_free_page_table(void **table, size_t size)
312 unsigned i, nr_tables = DIV_ROUND_UP(size, PAGE_SIZE);
314 for (i = 0; i < nr_tables; i++)
319 static void io_rsrc_data_free(struct io_rsrc_data *data)
321 size_t size = data->nr * sizeof(data->tags[0][0]);
324 io_free_page_table((void **)data->tags, size);
328 static __cold void **io_alloc_page_table(size_t size)
330 unsigned i, nr_tables = DIV_ROUND_UP(size, PAGE_SIZE);
331 size_t init_size = size;
334 table = kcalloc(nr_tables, sizeof(*table), GFP_KERNEL_ACCOUNT);
338 for (i = 0; i < nr_tables; i++) {
339 unsigned int this_size = min_t(size_t, size, PAGE_SIZE);
341 table[i] = kzalloc(this_size, GFP_KERNEL_ACCOUNT);
343 io_free_page_table(table, init_size);
351 __cold static int io_rsrc_data_alloc(struct io_ring_ctx *ctx,
352 rsrc_put_fn *do_put, u64 __user *utags,
353 unsigned nr, struct io_rsrc_data **pdata)
355 struct io_rsrc_data *data;
359 data = kzalloc(sizeof(*data), GFP_KERNEL);
362 data->tags = (u64 **)io_alloc_page_table(nr * sizeof(data->tags[0][0]));
370 data->do_put = do_put;
374 for (i = 0; i < nr; i++) {
375 u64 *tag_slot = io_get_tag_slot(data, i);
377 if (copy_from_user(tag_slot, &utags[i],
382 init_completion(&data->done);
386 io_rsrc_data_free(data);
390 static int __io_sqe_files_update(struct io_ring_ctx *ctx,
391 struct io_uring_rsrc_update2 *up,
394 u64 __user *tags = u64_to_user_ptr(up->tags);
395 __s32 __user *fds = u64_to_user_ptr(up->data);
396 struct io_rsrc_data *data = ctx->file_data;
397 struct io_fixed_file *file_slot;
401 bool needs_switch = false;
405 if (up->offset + nr_args > ctx->nr_user_files)
408 for (done = 0; done < nr_args; done++) {
411 if ((tags && copy_from_user(&tag, &tags[done], sizeof(tag))) ||
412 copy_from_user(&fd, &fds[done], sizeof(fd))) {
416 if ((fd == IORING_REGISTER_FILES_SKIP || fd == -1) && tag) {
420 if (fd == IORING_REGISTER_FILES_SKIP)
423 i = array_index_nospec(up->offset + done, ctx->nr_user_files);
424 file_slot = io_fixed_file_slot(&ctx->file_table, i);
426 if (file_slot->file_ptr) {
427 file = (struct file *)(file_slot->file_ptr & FFS_MASK);
428 err = io_queue_rsrc_removal(data, i, ctx->rsrc_node, file);
431 file_slot->file_ptr = 0;
432 io_file_bitmap_clear(&ctx->file_table, i);
442 * Don't allow io_uring instances to be registered. If
443 * UNIX isn't enabled, then this causes a reference
444 * cycle and this instance can never get freed. If UNIX
445 * is enabled we'll handle it just fine, but there's
446 * still no point in allowing a ring fd as it doesn't
447 * support regular read/write anyway.
449 if (io_is_uring_fops(file)) {
454 err = io_scm_file_account(ctx, file);
459 *io_get_tag_slot(data, i) = tag;
460 io_fixed_file_set(file_slot, file);
461 io_file_bitmap_set(&ctx->file_table, i);
466 io_rsrc_node_switch(ctx, data);
467 return done ? done : err;
470 static int __io_sqe_buffers_update(struct io_ring_ctx *ctx,
471 struct io_uring_rsrc_update2 *up,
472 unsigned int nr_args)
474 u64 __user *tags = u64_to_user_ptr(up->tags);
475 struct iovec iov, __user *iovs = u64_to_user_ptr(up->data);
476 struct page *last_hpage = NULL;
477 bool needs_switch = false;
483 if (up->offset + nr_args > ctx->nr_user_bufs)
486 for (done = 0; done < nr_args; done++) {
487 struct io_mapped_ubuf *imu;
488 int offset = up->offset + done;
491 err = io_copy_iov(ctx, &iov, iovs, done);
494 if (tags && copy_from_user(&tag, &tags[done], sizeof(tag))) {
498 err = io_buffer_validate(&iov);
501 if (!iov.iov_base && tag) {
505 err = io_sqe_buffer_register(ctx, &iov, &imu, &last_hpage);
509 i = array_index_nospec(offset, ctx->nr_user_bufs);
510 if (ctx->user_bufs[i] != ctx->dummy_ubuf) {
511 err = io_queue_rsrc_removal(ctx->buf_data, i,
512 ctx->rsrc_node, ctx->user_bufs[i]);
514 io_buffer_unmap(ctx, &imu);
517 ctx->user_bufs[i] = ctx->dummy_ubuf;
521 ctx->user_bufs[i] = imu;
522 *io_get_tag_slot(ctx->buf_data, offset) = tag;
526 io_rsrc_node_switch(ctx, ctx->buf_data);
527 return done ? done : err;
530 static int __io_register_rsrc_update(struct io_ring_ctx *ctx, unsigned type,
531 struct io_uring_rsrc_update2 *up,
537 if (check_add_overflow(up->offset, nr_args, &tmp))
539 err = io_rsrc_node_switch_start(ctx);
544 case IORING_RSRC_FILE:
545 return __io_sqe_files_update(ctx, up, nr_args);
546 case IORING_RSRC_BUFFER:
547 return __io_sqe_buffers_update(ctx, up, nr_args);
552 int io_register_files_update(struct io_ring_ctx *ctx, void __user *arg,
555 struct io_uring_rsrc_update2 up;
559 memset(&up, 0, sizeof(up));
560 if (copy_from_user(&up, arg, sizeof(struct io_uring_rsrc_update)))
562 if (up.resv || up.resv2)
564 return __io_register_rsrc_update(ctx, IORING_RSRC_FILE, &up, nr_args);
567 int io_register_rsrc_update(struct io_ring_ctx *ctx, void __user *arg,
568 unsigned size, unsigned type)
570 struct io_uring_rsrc_update2 up;
572 if (size != sizeof(up))
574 if (copy_from_user(&up, arg, sizeof(up)))
576 if (!up.nr || up.resv || up.resv2)
578 return __io_register_rsrc_update(ctx, type, &up, up.nr);
581 __cold int io_register_rsrc(struct io_ring_ctx *ctx, void __user *arg,
582 unsigned int size, unsigned int type)
584 struct io_uring_rsrc_register rr;
586 /* keep it extendible */
587 if (size != sizeof(rr))
590 memset(&rr, 0, sizeof(rr));
591 if (copy_from_user(&rr, arg, size))
593 if (!rr.nr || rr.resv2)
595 if (rr.flags & ~IORING_RSRC_REGISTER_SPARSE)
599 case IORING_RSRC_FILE:
600 if (rr.flags & IORING_RSRC_REGISTER_SPARSE && rr.data)
602 return io_sqe_files_register(ctx, u64_to_user_ptr(rr.data),
603 rr.nr, u64_to_user_ptr(rr.tags));
604 case IORING_RSRC_BUFFER:
605 if (rr.flags & IORING_RSRC_REGISTER_SPARSE && rr.data)
607 return io_sqe_buffers_register(ctx, u64_to_user_ptr(rr.data),
608 rr.nr, u64_to_user_ptr(rr.tags));
613 int io_files_update_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
615 struct io_rsrc_update *up = io_kiocb_to_cmd(req, struct io_rsrc_update);
617 if (unlikely(req->flags & (REQ_F_FIXED_FILE | REQ_F_BUFFER_SELECT)))
619 if (sqe->rw_flags || sqe->splice_fd_in)
622 up->offset = READ_ONCE(sqe->off);
623 up->nr_args = READ_ONCE(sqe->len);
626 up->arg = READ_ONCE(sqe->addr);
630 static int io_files_update_with_index_alloc(struct io_kiocb *req,
631 unsigned int issue_flags)
633 struct io_rsrc_update *up = io_kiocb_to_cmd(req, struct io_rsrc_update);
634 __s32 __user *fds = u64_to_user_ptr(up->arg);
639 if (!req->ctx->file_data)
642 for (done = 0; done < up->nr_args; done++) {
643 if (copy_from_user(&fd, &fds[done], sizeof(fd))) {
653 ret = io_fixed_fd_install(req, issue_flags, file,
654 IORING_FILE_INDEX_ALLOC);
657 if (copy_to_user(&fds[done], &ret, sizeof(ret))) {
658 __io_close_fixed(req->ctx, issue_flags, ret);
669 int io_files_update(struct io_kiocb *req, unsigned int issue_flags)
671 struct io_rsrc_update *up = io_kiocb_to_cmd(req, struct io_rsrc_update);
672 struct io_ring_ctx *ctx = req->ctx;
673 struct io_uring_rsrc_update2 up2;
676 up2.offset = up->offset;
683 if (up->offset == IORING_FILE_INDEX_ALLOC) {
684 ret = io_files_update_with_index_alloc(req, issue_flags);
686 io_ring_submit_lock(ctx, issue_flags);
687 ret = __io_register_rsrc_update(ctx, IORING_RSRC_FILE,
689 io_ring_submit_unlock(ctx, issue_flags);
694 io_req_set_res(req, ret, 0);
698 int io_queue_rsrc_removal(struct io_rsrc_data *data, unsigned idx,
699 struct io_rsrc_node *node, void *rsrc)
701 u64 *tag_slot = io_get_tag_slot(data, idx);
702 struct io_rsrc_put *prsrc;
703 bool inline_item = true;
705 if (!node->inline_items) {
707 node->inline_items++;
709 prsrc = kzalloc(sizeof(*prsrc), GFP_KERNEL);
715 prsrc->tag = *tag_slot;
719 list_add(&prsrc->list, &node->item_list);
723 void __io_sqe_files_unregister(struct io_ring_ctx *ctx)
727 for (i = 0; i < ctx->nr_user_files; i++) {
728 struct file *file = io_file_from_index(&ctx->file_table, i);
730 /* skip scm accounted files, they'll be freed by ->ring_sock */
731 if (!file || io_file_need_scm(file))
733 io_file_bitmap_clear(&ctx->file_table, i);
737 #if defined(CONFIG_UNIX)
738 if (ctx->ring_sock) {
739 struct sock *sock = ctx->ring_sock->sk;
742 while ((skb = skb_dequeue(&sock->sk_receive_queue)) != NULL)
746 io_free_file_tables(&ctx->file_table);
747 io_file_table_set_alloc_range(ctx, 0, 0);
748 io_rsrc_data_free(ctx->file_data);
749 ctx->file_data = NULL;
750 ctx->nr_user_files = 0;
753 int io_sqe_files_unregister(struct io_ring_ctx *ctx)
755 unsigned nr = ctx->nr_user_files;
762 * Quiesce may unlock ->uring_lock, and while it's not held
763 * prevent new requests using the table.
765 ctx->nr_user_files = 0;
766 ret = io_rsrc_ref_quiesce(ctx->file_data, ctx);
767 ctx->nr_user_files = nr;
769 __io_sqe_files_unregister(ctx);
774 * Ensure the UNIX gc is aware of our file set, so we are certain that
775 * the io_uring can be safely unregistered on process exit, even if we have
776 * loops in the file referencing. We account only files that can hold other
777 * files because otherwise they can't form a loop and so are not interesting
780 int __io_scm_file_account(struct io_ring_ctx *ctx, struct file *file)
782 #if defined(CONFIG_UNIX)
783 struct sock *sk = ctx->ring_sock->sk;
784 struct sk_buff_head *head = &sk->sk_receive_queue;
785 struct scm_fp_list *fpl;
788 if (likely(!io_file_need_scm(file)))
792 * See if we can merge this file into an existing skb SCM_RIGHTS
793 * file set. If there's no room, fall back to allocating a new skb
796 spin_lock_irq(&head->lock);
797 skb = skb_peek(head);
798 if (skb && UNIXCB(skb).fp->count < SCM_MAX_FD)
799 __skb_unlink(skb, head);
802 spin_unlock_irq(&head->lock);
805 fpl = kzalloc(sizeof(*fpl), GFP_KERNEL);
809 skb = alloc_skb(0, GFP_KERNEL);
815 fpl->user = get_uid(current_user());
816 fpl->max = SCM_MAX_FD;
819 UNIXCB(skb).fp = fpl;
821 skb->scm_io_uring = 1;
822 skb->destructor = unix_destruct_scm;
823 refcount_add(skb->truesize, &sk->sk_wmem_alloc);
826 fpl = UNIXCB(skb).fp;
827 fpl->fp[fpl->count++] = get_file(file);
828 unix_inflight(fpl->user, file);
829 skb_queue_head(head, skb);
835 static void io_rsrc_file_put(struct io_ring_ctx *ctx, struct io_rsrc_put *prsrc)
837 struct file *file = prsrc->file;
838 #if defined(CONFIG_UNIX)
839 struct sock *sock = ctx->ring_sock->sk;
840 struct sk_buff_head list, *head = &sock->sk_receive_queue;
844 if (!io_file_need_scm(file)) {
849 __skb_queue_head_init(&list);
852 * Find the skb that holds this file in its SCM_RIGHTS. When found,
853 * remove this entry and rearrange the file array.
855 skb = skb_dequeue(head);
857 struct scm_fp_list *fp;
860 for (i = 0; i < fp->count; i++) {
863 if (fp->fp[i] != file)
866 unix_notinflight(fp->user, fp->fp[i]);
867 left = fp->count - 1 - i;
869 memmove(&fp->fp[i], &fp->fp[i + 1],
870 left * sizeof(struct file *));
877 __skb_queue_tail(&list, skb);
887 __skb_queue_tail(&list, skb);
889 skb = skb_dequeue(head);
892 if (skb_peek(&list)) {
893 spin_lock_irq(&head->lock);
894 while ((skb = __skb_dequeue(&list)) != NULL)
895 __skb_queue_tail(head, skb);
896 spin_unlock_irq(&head->lock);
903 int io_sqe_files_register(struct io_ring_ctx *ctx, void __user *arg,
904 unsigned nr_args, u64 __user *tags)
906 __s32 __user *fds = (__s32 __user *) arg;
915 if (nr_args > IORING_MAX_FIXED_FILES)
917 if (nr_args > rlimit(RLIMIT_NOFILE))
919 ret = io_rsrc_node_switch_start(ctx);
922 ret = io_rsrc_data_alloc(ctx, io_rsrc_file_put, tags, nr_args,
927 if (!io_alloc_file_tables(&ctx->file_table, nr_args)) {
928 io_rsrc_data_free(ctx->file_data);
929 ctx->file_data = NULL;
933 for (i = 0; i < nr_args; i++, ctx->nr_user_files++) {
934 struct io_fixed_file *file_slot;
936 if (fds && copy_from_user(&fd, &fds[i], sizeof(fd))) {
940 /* allow sparse sets */
941 if (!fds || fd == -1) {
943 if (unlikely(*io_get_tag_slot(ctx->file_data, i)))
954 * Don't allow io_uring instances to be registered. If UNIX
955 * isn't enabled, then this causes a reference cycle and this
956 * instance can never get freed. If UNIX is enabled we'll
957 * handle it just fine, but there's still no point in allowing
958 * a ring fd as it doesn't support regular read/write anyway.
960 if (io_is_uring_fops(file)) {
964 ret = io_scm_file_account(ctx, file);
969 file_slot = io_fixed_file_slot(&ctx->file_table, i);
970 io_fixed_file_set(file_slot, file);
971 io_file_bitmap_set(&ctx->file_table, i);
974 /* default it to the whole table */
975 io_file_table_set_alloc_range(ctx, 0, ctx->nr_user_files);
976 io_rsrc_node_switch(ctx, NULL);
979 __io_sqe_files_unregister(ctx);
983 static void io_rsrc_buf_put(struct io_ring_ctx *ctx, struct io_rsrc_put *prsrc)
985 io_buffer_unmap(ctx, &prsrc->buf);
989 void __io_sqe_buffers_unregister(struct io_ring_ctx *ctx)
993 for (i = 0; i < ctx->nr_user_bufs; i++)
994 io_buffer_unmap(ctx, &ctx->user_bufs[i]);
995 kfree(ctx->user_bufs);
996 io_rsrc_data_free(ctx->buf_data);
997 ctx->user_bufs = NULL;
998 ctx->buf_data = NULL;
999 ctx->nr_user_bufs = 0;
1002 int io_sqe_buffers_unregister(struct io_ring_ctx *ctx)
1004 unsigned nr = ctx->nr_user_bufs;
1011 * Quiesce may unlock ->uring_lock, and while it's not held
1012 * prevent new requests using the table.
1014 ctx->nr_user_bufs = 0;
1015 ret = io_rsrc_ref_quiesce(ctx->buf_data, ctx);
1016 ctx->nr_user_bufs = nr;
1018 __io_sqe_buffers_unregister(ctx);
1023 * Not super efficient, but this is just a registration time. And we do cache
1024 * the last compound head, so generally we'll only do a full search if we don't
1027 * We check if the given compound head page has already been accounted, to
1028 * avoid double accounting it. This allows us to account the full size of the
1029 * page, not just the constituent pages of a huge page.
1031 static bool headpage_already_acct(struct io_ring_ctx *ctx, struct page **pages,
1032 int nr_pages, struct page *hpage)
1036 /* check current page array */
1037 for (i = 0; i < nr_pages; i++) {
1038 if (!PageCompound(pages[i]))
1040 if (compound_head(pages[i]) == hpage)
1044 /* check previously registered pages */
1045 for (i = 0; i < ctx->nr_user_bufs; i++) {
1046 struct io_mapped_ubuf *imu = ctx->user_bufs[i];
1048 for (j = 0; j < imu->nr_bvecs; j++) {
1049 if (!PageCompound(imu->bvec[j].bv_page))
1051 if (compound_head(imu->bvec[j].bv_page) == hpage)
1059 static int io_buffer_account_pin(struct io_ring_ctx *ctx, struct page **pages,
1060 int nr_pages, struct io_mapped_ubuf *imu,
1061 struct page **last_hpage)
1065 imu->acct_pages = 0;
1066 for (i = 0; i < nr_pages; i++) {
1067 if (!PageCompound(pages[i])) {
1072 hpage = compound_head(pages[i]);
1073 if (hpage == *last_hpage)
1075 *last_hpage = hpage;
1076 if (headpage_already_acct(ctx, pages, i, hpage))
1078 imu->acct_pages += page_size(hpage) >> PAGE_SHIFT;
1082 if (!imu->acct_pages)
1085 ret = io_account_mem(ctx, imu->acct_pages);
1087 imu->acct_pages = 0;
1091 struct page **io_pin_pages(unsigned long ubuf, unsigned long len, int *npages)
1093 unsigned long start, end, nr_pages;
1094 struct vm_area_struct **vmas = NULL;
1095 struct page **pages = NULL;
1096 int i, pret, ret = -ENOMEM;
1098 end = (ubuf + len + PAGE_SIZE - 1) >> PAGE_SHIFT;
1099 start = ubuf >> PAGE_SHIFT;
1100 nr_pages = end - start;
1102 pages = kvmalloc_array(nr_pages, sizeof(struct page *), GFP_KERNEL);
1106 vmas = kvmalloc_array(nr_pages, sizeof(struct vm_area_struct *),
1112 mmap_read_lock(current->mm);
1113 pret = pin_user_pages(ubuf, nr_pages, FOLL_WRITE | FOLL_LONGTERM,
1115 if (pret == nr_pages) {
1116 struct file *file = vmas[0]->vm_file;
1118 /* don't support file backed memory */
1119 for (i = 0; i < nr_pages; i++) {
1120 if (vmas[i]->vm_file != file) {
1126 if (!vma_is_shmem(vmas[i]) && !is_file_hugepages(file)) {
1133 ret = pret < 0 ? pret : -EFAULT;
1135 mmap_read_unlock(current->mm);
1138 * if we did partial map, or found file backed vmas,
1139 * release any pages we did get
1142 unpin_user_pages(pages, pret);
1150 pages = ERR_PTR(ret);
1155 static int io_sqe_buffer_register(struct io_ring_ctx *ctx, struct iovec *iov,
1156 struct io_mapped_ubuf **pimu,
1157 struct page **last_hpage)
1159 struct io_mapped_ubuf *imu = NULL;
1160 struct page **pages = NULL;
1163 int ret, nr_pages, i;
1164 struct folio *folio = NULL;
1166 *pimu = ctx->dummy_ubuf;
1171 pages = io_pin_pages((unsigned long) iov->iov_base, iov->iov_len,
1173 if (IS_ERR(pages)) {
1174 ret = PTR_ERR(pages);
1179 /* If it's a huge page, try to coalesce them into a single bvec entry */
1181 folio = page_folio(pages[0]);
1182 for (i = 1; i < nr_pages; i++) {
1183 if (page_folio(pages[i]) != folio) {
1190 * The pages are bound to the folio, it doesn't
1191 * actually unpin them but drops all but one reference,
1192 * which is usually put down by io_buffer_unmap().
1193 * Note, needs a better helper.
1195 unpin_user_pages(&pages[1], nr_pages - 1);
1200 imu = kvmalloc(struct_size(imu, bvec, nr_pages), GFP_KERNEL);
1204 ret = io_buffer_account_pin(ctx, pages, nr_pages, imu, last_hpage);
1206 unpin_user_pages(pages, nr_pages);
1210 off = (unsigned long) iov->iov_base & ~PAGE_MASK;
1211 size = iov->iov_len;
1212 /* store original address for later verification */
1213 imu->ubuf = (unsigned long) iov->iov_base;
1214 imu->ubuf_end = imu->ubuf + iov->iov_len;
1215 imu->nr_bvecs = nr_pages;
1220 bvec_set_page(&imu->bvec[0], pages[0], size, off);
1223 for (i = 0; i < nr_pages; i++) {
1226 vec_len = min_t(size_t, size, PAGE_SIZE - off);
1227 bvec_set_page(&imu->bvec[i], pages[i], vec_len, off);
1238 static int io_buffers_map_alloc(struct io_ring_ctx *ctx, unsigned int nr_args)
1240 ctx->user_bufs = kcalloc(nr_args, sizeof(*ctx->user_bufs), GFP_KERNEL);
1241 return ctx->user_bufs ? 0 : -ENOMEM;
1244 int io_sqe_buffers_register(struct io_ring_ctx *ctx, void __user *arg,
1245 unsigned int nr_args, u64 __user *tags)
1247 struct page *last_hpage = NULL;
1248 struct io_rsrc_data *data;
1252 BUILD_BUG_ON(IORING_MAX_REG_BUFFERS >= (1u << 16));
1256 if (!nr_args || nr_args > IORING_MAX_REG_BUFFERS)
1258 ret = io_rsrc_node_switch_start(ctx);
1261 ret = io_rsrc_data_alloc(ctx, io_rsrc_buf_put, tags, nr_args, &data);
1264 ret = io_buffers_map_alloc(ctx, nr_args);
1266 io_rsrc_data_free(data);
1270 for (i = 0; i < nr_args; i++, ctx->nr_user_bufs++) {
1272 ret = io_copy_iov(ctx, &iov, arg, i);
1275 ret = io_buffer_validate(&iov);
1279 memset(&iov, 0, sizeof(iov));
1282 if (!iov.iov_base && *io_get_tag_slot(data, i)) {
1287 ret = io_sqe_buffer_register(ctx, &iov, &ctx->user_bufs[i],
1293 WARN_ON_ONCE(ctx->buf_data);
1295 ctx->buf_data = data;
1297 __io_sqe_buffers_unregister(ctx);
1299 io_rsrc_node_switch(ctx, NULL);
1303 int io_import_fixed(int ddir, struct iov_iter *iter,
1304 struct io_mapped_ubuf *imu,
1305 u64 buf_addr, size_t len)
1310 if (WARN_ON_ONCE(!imu))
1312 if (unlikely(check_add_overflow(buf_addr, (u64)len, &buf_end)))
1314 /* not inside the mapped region */
1315 if (unlikely(buf_addr < imu->ubuf || buf_end > imu->ubuf_end))
1319 * Might not be a start of buffer, set size appropriately
1320 * and advance us to the beginning.
1322 offset = buf_addr - imu->ubuf;
1323 iov_iter_bvec(iter, ddir, imu->bvec, imu->nr_bvecs, offset + len);
1327 * Don't use iov_iter_advance() here, as it's really slow for
1328 * using the latter parts of a big fixed buffer - it iterates
1329 * over each segment manually. We can cheat a bit here, because
1332 * 1) it's a BVEC iter, we set it up
1333 * 2) all bvecs are PAGE_SIZE in size, except potentially the
1334 * first and last bvec
1336 * So just find our index, and adjust the iterator afterwards.
1337 * If the offset is within the first bvec (or the whole first
1338 * bvec, just use iov_iter_advance(). This makes it easier
1339 * since we can just skip the first segment, which may not
1340 * be PAGE_SIZE aligned.
1342 const struct bio_vec *bvec = imu->bvec;
1344 if (offset <= bvec->bv_len) {
1346 * Note, huge pages buffers consists of one large
1347 * bvec entry and should always go this way. The other
1348 * branch doesn't expect non PAGE_SIZE'd chunks.
1351 iter->nr_segs = bvec->bv_len;
1352 iter->count -= offset;
1353 iter->iov_offset = offset;
1355 unsigned long seg_skip;
1357 /* skip first vec */
1358 offset -= bvec->bv_len;
1359 seg_skip = 1 + (offset >> PAGE_SHIFT);
1361 iter->bvec = bvec + seg_skip;
1362 iter->nr_segs -= seg_skip;
1363 iter->count -= bvec->bv_len + offset;
1364 iter->iov_offset = offset & ~PAGE_MASK;