1 // SPDX-License-Identifier: GPL-2.0
3 * Functions related to mapping data to requests
5 #include <linux/kernel.h>
6 #include <linux/sched/task_stack.h>
7 #include <linux/module.h>
9 #include <linux/blkdev.h>
10 #include <linux/uio.h>
15 bool is_our_pages : 1;
16 bool is_null_mapped : 1;
21 static struct bio_map_data *bio_alloc_map_data(struct iov_iter *data,
24 struct bio_map_data *bmd;
26 if (data->nr_segs > UIO_MAXIOV)
29 bmd = kmalloc(struct_size(bmd, iov, data->nr_segs), gfp_mask);
33 if (iter_is_iovec(data)) {
34 memcpy(bmd->iov, iter_iov(data), sizeof(struct iovec) * data->nr_segs);
35 bmd->iter.__iov = bmd->iov;
41 * bio_copy_from_iter - copy all pages from iov_iter to bio
42 * @bio: The &struct bio which describes the I/O as destination
43 * @iter: iov_iter as source
45 * Copy all pages from iov_iter to bio.
46 * Returns 0 on success, or error on failure.
48 static int bio_copy_from_iter(struct bio *bio, struct iov_iter *iter)
51 struct bvec_iter_all iter_all;
53 bio_for_each_segment_all(bvec, bio, iter_all) {
56 ret = copy_page_from_iter(bvec->bv_page,
61 if (!iov_iter_count(iter))
64 if (ret < bvec->bv_len)
72 * bio_copy_to_iter - copy all pages from bio to iov_iter
73 * @bio: The &struct bio which describes the I/O as source
74 * @iter: iov_iter as destination
76 * Copy all pages from bio to iov_iter.
77 * Returns 0 on success, or error on failure.
79 static int bio_copy_to_iter(struct bio *bio, struct iov_iter iter)
82 struct bvec_iter_all iter_all;
84 bio_for_each_segment_all(bvec, bio, iter_all) {
87 ret = copy_page_to_iter(bvec->bv_page,
92 if (!iov_iter_count(&iter))
95 if (ret < bvec->bv_len)
103 * bio_uncopy_user - finish previously mapped bio
104 * @bio: bio being terminated
106 * Free pages allocated from bio_copy_user_iov() and write back data
107 * to user space in case of a read.
109 static int bio_uncopy_user(struct bio *bio)
111 struct bio_map_data *bmd = bio->bi_private;
114 if (!bmd->is_null_mapped) {
116 * if we're in a workqueue, the request is orphaned, so
117 * don't copy into a random user address space, just free
118 * and return -EINTR so user space doesn't expect any data.
122 else if (bio_data_dir(bio) == READ)
123 ret = bio_copy_to_iter(bio, bmd->iter);
124 if (bmd->is_our_pages)
131 static int bio_copy_user_iov(struct request *rq, struct rq_map_data *map_data,
132 struct iov_iter *iter, gfp_t gfp_mask)
134 struct bio_map_data *bmd;
139 unsigned int len = iter->count;
140 unsigned int offset = map_data ? offset_in_page(map_data->offset) : 0;
142 bmd = bio_alloc_map_data(iter, gfp_mask);
147 * We need to do a deep copy of the iov_iter including the iovecs.
148 * The caller provided iov might point to an on-stack or otherwise
151 bmd->is_our_pages = !map_data;
152 bmd->is_null_mapped = (map_data && map_data->null_mapped);
154 nr_pages = bio_max_segs(DIV_ROUND_UP(offset + len, PAGE_SIZE));
157 bio = bio_kmalloc(nr_pages, gfp_mask);
160 bio_init(bio, NULL, bio->bi_inline_vecs, nr_pages, req_op(rq));
163 nr_pages = 1U << map_data->page_order;
164 i = map_data->offset / PAGE_SIZE;
167 unsigned int bytes = PAGE_SIZE;
175 if (i == map_data->nr_entries * nr_pages) {
180 page = map_data->pages[i / nr_pages];
181 page += (i % nr_pages);
185 page = alloc_page(GFP_NOIO | gfp_mask);
192 if (bio_add_pc_page(rq->q, bio, page, bytes, offset) < bytes) {
203 map_data->offset += bio->bi_iter.bi_size;
208 if ((iov_iter_rw(iter) == WRITE &&
209 (!map_data || !map_data->null_mapped)) ||
210 (map_data && map_data->from_user)) {
211 ret = bio_copy_from_iter(bio, iter);
215 if (bmd->is_our_pages)
217 iov_iter_advance(iter, bio->bi_iter.bi_size);
220 bio->bi_private = bmd;
222 ret = blk_rq_append_bio(rq, bio);
236 static void blk_mq_map_bio_put(struct bio *bio)
238 if (bio->bi_opf & REQ_ALLOC_CACHE) {
246 static struct bio *blk_rq_map_bio_alloc(struct request *rq,
247 unsigned int nr_vecs, gfp_t gfp_mask)
251 if (rq->cmd_flags & REQ_ALLOC_CACHE) {
252 bio = bio_alloc_bioset(NULL, nr_vecs, rq->cmd_flags, gfp_mask,
257 bio = bio_kmalloc(nr_vecs, gfp_mask);
260 bio_init(bio, NULL, bio->bi_inline_vecs, nr_vecs, req_op(rq));
265 static int bio_map_user_iov(struct request *rq, struct iov_iter *iter,
268 iov_iter_extraction_t extraction_flags = 0;
269 unsigned int max_sectors = queue_max_hw_sectors(rq->q);
270 unsigned int nr_vecs = iov_iter_npages(iter, BIO_MAX_VECS);
275 if (!iov_iter_count(iter))
278 bio = blk_rq_map_bio_alloc(rq, nr_vecs, gfp_mask);
282 if (blk_queue_pci_p2pdma(rq->q))
283 extraction_flags |= ITER_ALLOW_P2PDMA;
284 if (iov_iter_extract_will_pin(iter))
285 bio_set_flag(bio, BIO_PAGE_PINNED);
287 while (iov_iter_count(iter)) {
288 struct page *stack_pages[UIO_FASTIOV];
289 struct page **pages = stack_pages;
294 if (nr_vecs > ARRAY_SIZE(stack_pages))
297 bytes = iov_iter_extract_pages(iter, &pages, LONG_MAX,
298 nr_vecs, extraction_flags, &offs);
299 if (unlikely(bytes <= 0)) {
300 ret = bytes ? bytes : -EFAULT;
304 npages = DIV_ROUND_UP(offs + bytes, PAGE_SIZE);
306 if (unlikely(offs & queue_dma_alignment(rq->q)))
309 for (j = 0; j < npages; j++) {
310 struct page *page = pages[j];
311 unsigned int n = PAGE_SIZE - offs;
312 bool same_page = false;
317 if (!bio_add_hw_page(rq->q, bio, page, n, offs,
318 max_sectors, &same_page)) {
320 bio_release_page(bio, page);
329 * release the pages we didn't map into the bio, if any
332 bio_release_page(bio, pages[j++]);
333 if (pages != stack_pages)
335 /* couldn't stuff something into bio? */
337 iov_iter_revert(iter, bytes);
342 ret = blk_rq_append_bio(rq, bio);
348 bio_release_pages(bio, false);
349 blk_mq_map_bio_put(bio);
353 static void bio_invalidate_vmalloc_pages(struct bio *bio)
355 #ifdef ARCH_IMPLEMENTS_FLUSH_KERNEL_VMAP_RANGE
356 if (bio->bi_private && !op_is_write(bio_op(bio))) {
357 unsigned long i, len = 0;
359 for (i = 0; i < bio->bi_vcnt; i++)
360 len += bio->bi_io_vec[i].bv_len;
361 invalidate_kernel_vmap_range(bio->bi_private, len);
366 static void bio_map_kern_endio(struct bio *bio)
368 bio_invalidate_vmalloc_pages(bio);
374 * bio_map_kern - map kernel address into bio
375 * @q: the struct request_queue for the bio
376 * @data: pointer to buffer to map
377 * @len: length in bytes
378 * @gfp_mask: allocation flags for bio allocation
380 * Map the kernel address into a bio suitable for io to a block
381 * device. Returns an error pointer in case of error.
383 static struct bio *bio_map_kern(struct request_queue *q, void *data,
384 unsigned int len, gfp_t gfp_mask)
386 unsigned long kaddr = (unsigned long)data;
387 unsigned long end = (kaddr + len + PAGE_SIZE - 1) >> PAGE_SHIFT;
388 unsigned long start = kaddr >> PAGE_SHIFT;
389 const int nr_pages = end - start;
390 bool is_vmalloc = is_vmalloc_addr(data);
395 bio = bio_kmalloc(nr_pages, gfp_mask);
397 return ERR_PTR(-ENOMEM);
398 bio_init(bio, NULL, bio->bi_inline_vecs, nr_pages, 0);
401 flush_kernel_vmap_range(data, len);
402 bio->bi_private = data;
405 offset = offset_in_page(kaddr);
406 for (i = 0; i < nr_pages; i++) {
407 unsigned int bytes = PAGE_SIZE - offset;
416 page = virt_to_page(data);
418 page = vmalloc_to_page(data);
419 if (bio_add_pc_page(q, bio, page, bytes,
421 /* we don't support partial mappings */
424 return ERR_PTR(-EINVAL);
432 bio->bi_end_io = bio_map_kern_endio;
436 static void bio_copy_kern_endio(struct bio *bio)
443 static void bio_copy_kern_endio_read(struct bio *bio)
445 char *p = bio->bi_private;
446 struct bio_vec *bvec;
447 struct bvec_iter_all iter_all;
449 bio_for_each_segment_all(bvec, bio, iter_all) {
450 memcpy_from_bvec(p, bvec);
454 bio_copy_kern_endio(bio);
458 * bio_copy_kern - copy kernel address into bio
459 * @q: the struct request_queue for the bio
460 * @data: pointer to buffer to copy
461 * @len: length in bytes
462 * @gfp_mask: allocation flags for bio and page allocation
463 * @reading: data direction is READ
465 * copy the kernel address into a bio suitable for io to a block
466 * device. Returns an error pointer in case of error.
468 static struct bio *bio_copy_kern(struct request_queue *q, void *data,
469 unsigned int len, gfp_t gfp_mask, int reading)
471 unsigned long kaddr = (unsigned long)data;
472 unsigned long end = (kaddr + len + PAGE_SIZE - 1) >> PAGE_SHIFT;
473 unsigned long start = kaddr >> PAGE_SHIFT;
482 return ERR_PTR(-EINVAL);
484 nr_pages = end - start;
485 bio = bio_kmalloc(nr_pages, gfp_mask);
487 return ERR_PTR(-ENOMEM);
488 bio_init(bio, NULL, bio->bi_inline_vecs, nr_pages, 0);
492 unsigned int bytes = PAGE_SIZE;
497 page = alloc_page(GFP_NOIO | __GFP_ZERO | gfp_mask);
502 memcpy(page_address(page), p, bytes);
504 if (bio_add_pc_page(q, bio, page, bytes, 0) < bytes)
512 bio->bi_end_io = bio_copy_kern_endio_read;
513 bio->bi_private = data;
515 bio->bi_end_io = bio_copy_kern_endio;
524 return ERR_PTR(-ENOMEM);
528 * Append a bio to a passthrough request. Only works if the bio can be merged
529 * into the request based on the driver constraints.
531 int blk_rq_append_bio(struct request *rq, struct bio *bio)
533 struct bvec_iter iter;
535 unsigned int nr_segs = 0;
537 bio_for_each_bvec(bv, bio, iter)
541 blk_rq_bio_prep(rq, bio, nr_segs);
543 if (!ll_back_merge_fn(rq, bio, nr_segs))
545 rq->biotail->bi_next = bio;
547 rq->__data_len += (bio)->bi_iter.bi_size;
548 bio_crypt_free_ctx(bio);
553 EXPORT_SYMBOL(blk_rq_append_bio);
555 /* Prepare bio for passthrough IO given ITER_BVEC iter */
556 static int blk_rq_map_user_bvec(struct request *rq, const struct iov_iter *iter)
558 struct request_queue *q = rq->q;
559 size_t nr_iter = iov_iter_count(iter);
560 size_t nr_segs = iter->nr_segs;
561 struct bio_vec *bvecs, *bvprvp = NULL;
562 const struct queue_limits *lim = &q->limits;
563 unsigned int nsegs = 0, bytes = 0;
567 if (!nr_iter || (nr_iter >> SECTOR_SHIFT) > queue_max_hw_sectors(q))
569 if (nr_segs > queue_max_segments(q))
572 /* no iovecs to alloc, as we already have a BVEC iterator */
573 bio = blk_rq_map_bio_alloc(rq, 0, GFP_KERNEL);
577 bio_iov_bvec_set(bio, (struct iov_iter *)iter);
578 blk_rq_bio_prep(rq, bio, nr_segs);
580 /* loop to perform a bunch of sanity checks */
581 bvecs = (struct bio_vec *)iter->bvec;
582 for (i = 0; i < nr_segs; i++) {
583 struct bio_vec *bv = &bvecs[i];
586 * If the queue doesn't support SG gaps and adding this
587 * offset would create a gap, fallback to copy.
589 if (bvprvp && bvec_gap_to_prev(lim, bvprvp, bv->bv_offset)) {
590 blk_mq_map_bio_put(bio);
593 /* check full condition */
594 if (nsegs >= nr_segs || bytes > UINT_MAX - bv->bv_len)
596 if (bytes + bv->bv_len > nr_iter)
598 if (bv->bv_offset + bv->bv_len > PAGE_SIZE)
607 blk_mq_map_bio_put(bio);
612 * blk_rq_map_user_iov - map user data to a request, for passthrough requests
613 * @q: request queue where request should be inserted
614 * @rq: request to map data to
615 * @map_data: pointer to the rq_map_data holding pages (if necessary)
616 * @iter: iovec iterator
617 * @gfp_mask: memory allocation flags
620 * Data will be mapped directly for zero copy I/O, if possible. Otherwise
621 * a kernel bounce buffer is used.
623 * A matching blk_rq_unmap_user() must be issued at the end of I/O, while
624 * still in process context.
626 int blk_rq_map_user_iov(struct request_queue *q, struct request *rq,
627 struct rq_map_data *map_data,
628 const struct iov_iter *iter, gfp_t gfp_mask)
630 bool copy = false, map_bvec = false;
631 unsigned long align = q->dma_pad_mask | queue_dma_alignment(q);
632 struct bio *bio = NULL;
638 else if (blk_queue_may_bounce(q))
640 else if (iov_iter_alignment(iter) & align)
642 else if (iov_iter_is_bvec(iter))
644 else if (!user_backed_iter(iter))
646 else if (queue_virt_boundary(q))
647 copy = queue_virt_boundary(q) & iov_iter_gap_alignment(iter);
650 ret = blk_rq_map_user_bvec(rq, iter);
653 if (ret != -EREMOTEIO)
655 /* fall back to copying the data on limits mismatches */
662 ret = bio_copy_user_iov(rq, map_data, &i, gfp_mask);
664 ret = bio_map_user_iov(rq, &i, gfp_mask);
669 } while (iov_iter_count(&i));
674 blk_rq_unmap_user(bio);
679 EXPORT_SYMBOL(blk_rq_map_user_iov);
681 int blk_rq_map_user(struct request_queue *q, struct request *rq,
682 struct rq_map_data *map_data, void __user *ubuf,
683 unsigned long len, gfp_t gfp_mask)
686 int ret = import_ubuf(rq_data_dir(rq), ubuf, len, &i);
688 if (unlikely(ret < 0))
691 return blk_rq_map_user_iov(q, rq, map_data, &i, gfp_mask);
693 EXPORT_SYMBOL(blk_rq_map_user);
695 int blk_rq_map_user_io(struct request *req, struct rq_map_data *map_data,
696 void __user *ubuf, unsigned long buf_len, gfp_t gfp_mask,
697 bool vec, int iov_count, bool check_iter_count, int rw)
702 struct iovec fast_iov[UIO_FASTIOV];
703 struct iovec *iov = fast_iov;
704 struct iov_iter iter;
706 ret = import_iovec(rw, ubuf, iov_count ? iov_count : buf_len,
707 UIO_FASTIOV, &iov, &iter);
712 /* SG_IO howto says that the shorter of the two wins */
713 iov_iter_truncate(&iter, buf_len);
714 if (check_iter_count && !iov_iter_count(&iter)) {
720 ret = blk_rq_map_user_iov(req->q, req, map_data, &iter,
723 } else if (buf_len) {
724 ret = blk_rq_map_user(req->q, req, map_data, ubuf, buf_len,
729 EXPORT_SYMBOL(blk_rq_map_user_io);
732 * blk_rq_unmap_user - unmap a request with user data
733 * @bio: start of bio list
736 * Unmap a rq previously mapped by blk_rq_map_user(). The caller must
737 * supply the original rq->bio from the blk_rq_map_user() return, since
738 * the I/O completion may have changed rq->bio.
740 int blk_rq_unmap_user(struct bio *bio)
742 struct bio *next_bio;
746 if (bio->bi_private) {
747 ret2 = bio_uncopy_user(bio);
751 bio_release_pages(bio, bio_data_dir(bio) == READ);
756 blk_mq_map_bio_put(next_bio);
761 EXPORT_SYMBOL(blk_rq_unmap_user);
764 * blk_rq_map_kern - map kernel data to a request, for passthrough requests
765 * @q: request queue where request should be inserted
766 * @rq: request to fill
767 * @kbuf: the kernel buffer
768 * @len: length of user data
769 * @gfp_mask: memory allocation flags
772 * Data will be mapped directly if possible. Otherwise a bounce
773 * buffer is used. Can be called multiple times to append multiple
776 int blk_rq_map_kern(struct request_queue *q, struct request *rq, void *kbuf,
777 unsigned int len, gfp_t gfp_mask)
779 int reading = rq_data_dir(rq) == READ;
780 unsigned long addr = (unsigned long) kbuf;
784 if (len > (queue_max_hw_sectors(q) << 9))
789 if (!blk_rq_aligned(q, addr, len) || object_is_on_stack(kbuf) ||
790 blk_queue_may_bounce(q))
791 bio = bio_copy_kern(q, kbuf, len, gfp_mask, reading);
793 bio = bio_map_kern(q, kbuf, len, gfp_mask);
798 bio->bi_opf &= ~REQ_OP_MASK;
799 bio->bi_opf |= req_op(rq);
801 ret = blk_rq_append_bio(rq, bio);
808 EXPORT_SYMBOL(blk_rq_map_kern);