Release 4.14 block/blk-map.c

// SPDX-License-Identifier: GPL-2.0
/*
 * Functions related to mapping data to requests
 */
#include <linux/kernel.h>
#include <linux/sched/task_stack.h>
#include <linux/module.h>
#include <linux/bio.h>
#include <linux/blkdev.h>
#include <linux/uio.h>

#include "blk.h"

/*
 * Append a bio to a passthrough request.  Only works can be merged into
 * the request based on the driver constraints.
 */


int blk_rq_append_bio(struct request *rq, struct bio *bio)
{
	blk_queue_bounce(rq->q, &bio);

	if (!rq->bio) {
		blk_rq_bio_prep(rq->q, rq, bio);
	} else {
		if (!ll_back_merge_fn(rq->q, rq, bio))
			return -EINVAL;

		rq->biotail->bi_next = bio;
		rq->biotail = bio;
		rq->__data_len += bio->bi_iter.bi_size;
	}

	return 0;
}
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Jens Axboe
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77.42%
1
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Christoph Hellwig
18
19.35%
2
40.00%
Kent Overstreet
2
2.15%
1
20.00%
Tejun Heo
1
1.08%
1
20.00%
Total
93
100.00%
5
100.00%


EXPORT_SYMBOL(blk_rq_append_bio);



static int __blk_rq_unmap_user(struct bio *bio)
{
	int ret = 0;

	if (bio) {
		if (bio_flagged(bio, BIO_USER_MAPPED))
			bio_unmap_user(bio);
		else
			ret = bio_uncopy_user(bio);
	}

	return ret;
}

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static int __blk_rq_map_user_iov(struct request *rq,
		struct rq_map_data *map_data, struct iov_iter *iter,
		gfp_t gfp_mask, bool copy)
{
	struct request_queue *q = rq->q;
	struct bio *bio, *orig_bio;
	int ret;

	if (copy)
		bio = bio_copy_user_iov(q, map_data, iter, gfp_mask);
	else
		bio = bio_map_user_iov(q, iter, gfp_mask);

	if (IS_ERR(bio))
		return PTR_ERR(bio);

	bio->bi_opf &= ~REQ_OP_MASK;
	bio->bi_opf |= req_op(rq);

	if (map_data && map_data->null_mapped)
		bio_set_flag(bio, BIO_NULL_MAPPED);

	iov_iter_advance(iter, bio->bi_iter.bi_size);
	if (map_data)
		map_data->offset += bio->bi_iter.bi_size;

	orig_bio = bio;

	/*
         * We link the bounce buffer in and could have to traverse it
         * later so we have to get a ref to prevent it from being freed
         */
	ret = blk_rq_append_bio(rq, bio);
	bio_get(bio);
	if (ret) {
		bio_endio(bio);
		__blk_rq_unmap_user(orig_bio);
		bio_put(bio);
		return ret;
	}

	return 0;
}

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/**
 * blk_rq_map_user_iov - map user data to a request, for passthrough requests
 * @q:          request queue where request should be inserted
 * @rq:         request to map data to
 * @map_data:   pointer to the rq_map_data holding pages (if necessary)
 * @iter:       iovec iterator
 * @gfp_mask:   memory allocation flags
 *
 * Description:
 *    Data will be mapped directly for zero copy I/O, if possible. Otherwise
 *    a kernel bounce buffer is used.
 *
 *    A matching blk_rq_unmap_user() must be issued at the end of I/O, while
 *    still in process context.
 *
 *    Note: The mapped bio may need to be bounced through blk_queue_bounce()
 *    before being submitted to the device, as pages mapped may be out of
 *    reach. It's the callers responsibility to make sure this happens. The
 *    original bio must be passed back in to blk_rq_unmap_user() for proper
 *    unmapping.
 */


int blk_rq_map_user_iov(struct request_queue *q, struct request *rq,
			struct rq_map_data *map_data,
			const struct iov_iter *iter, gfp_t gfp_mask)
{
	bool copy = false;
	unsigned long align = q->dma_pad_mask | queue_dma_alignment(q);
	struct bio *bio = NULL;
	struct iov_iter i;
	int ret;

	if (!iter_is_iovec(iter))
		goto fail;

	if (map_data)
		copy = true;
	else if (iov_iter_alignment(iter) & align)
		copy = true;
	else if (queue_virt_boundary(q))
		copy = queue_virt_boundary(q) & iov_iter_gap_alignment(iter);

	i = *iter;
	do {
		ret =__blk_rq_map_user_iov(rq, map_data, &i, gfp_mask, copy);
		if (ret)
			goto unmap_rq;
		if (!bio)
			bio = rq->bio;
	} while (iov_iter_count(&i));

	if (!bio_flagged(bio, BIO_USER_MAPPED))
		rq->rq_flags |= RQF_COPY_USER;
	return 0;

unmap_rq:
	__blk_rq_unmap_user(bio);
fail:
	rq->bio = NULL;
	return -EINVAL;
}
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Christoph Hellwig
65
32.02%
3
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Jens Axboe
41
20.20%
2
13.33%
Al Viro
38
18.72%
2
13.33%
FUJITA Tomonori
35
17.24%
4
26.67%
Linus Torvalds
13
6.40%
1
6.67%
Sagi Grimberg
5
2.46%
1
6.67%
Kent Overstreet
3
1.48%
1
6.67%
Xiaotian Feng
3
1.48%
1
6.67%
Total
203
100.00%
15
100.00%


EXPORT_SYMBOL(blk_rq_map_user_iov);



int blk_rq_map_user(struct request_queue *q, struct request *rq,
		    struct rq_map_data *map_data, void __user *ubuf,
		    unsigned long len, gfp_t gfp_mask)
{
	struct iovec iov;
	struct iov_iter i;
	int ret = import_single_range(rq_data_dir(rq), ubuf, len, &iov, &i);

	if (unlikely(ret < 0))
		return ret;

	return blk_rq_map_user_iov(q, rq, map_data, &i, gfp_mask);
}
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1
33.33%
Kent Overstreet
20
22.73%
1
33.33%
Total
88
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3
100.00%


EXPORT_SYMBOL(blk_rq_map_user);

/**
 * blk_rq_unmap_user - unmap a request with user data
 * @bio:               start of bio list
 *
 * Description:
 *    Unmap a rq previously mapped by blk_rq_map_user(). The caller must
 *    supply the original rq->bio from the blk_rq_map_user() return, since
 *    the I/O completion may have changed rq->bio.
 */


int blk_rq_unmap_user(struct bio *bio)
{
	struct bio *mapped_bio;
	int ret = 0, ret2;

	while (bio) {
		mapped_bio = bio;
		if (unlikely(bio_flagged(bio, BIO_BOUNCED)))
			mapped_bio = bio->bi_private;

		ret2 = __blk_rq_unmap_user(mapped_bio);
		if (ret2 && !ret)
			ret = ret2;

		mapped_bio = bio;
		bio = bio->bi_next;
		bio_put(mapped_bio);
	}

	return ret;
}
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EXPORT_SYMBOL(blk_rq_unmap_user);

/**
 * blk_rq_map_kern - map kernel data to a request, for passthrough requests
 * @q:          request queue where request should be inserted
 * @rq:         request to fill
 * @kbuf:       the kernel buffer
 * @len:        length of user data
 * @gfp_mask:   memory allocation flags
 *
 * Description:
 *    Data will be mapped directly if possible. Otherwise a bounce
 *    buffer is used. Can be called multiple times to append multiple
 *    buffers.
 */


int blk_rq_map_kern(struct request_queue *q, struct request *rq, void *kbuf,
		    unsigned int len, gfp_t gfp_mask)
{
	int reading = rq_data_dir(rq) == READ;
	unsigned long addr = (unsigned long) kbuf;
	int do_copy = 0;
	struct bio *bio;
	int ret;

	if (len > (queue_max_hw_sectors(q) << 9))
		return -EINVAL;
	if (!len || !kbuf)
		return -EINVAL;

	do_copy = !blk_rq_aligned(q, addr, len) || object_is_on_stack(kbuf);
	if (do_copy)
		bio = bio_copy_kern(q, kbuf, len, gfp_mask, reading);
	else
		bio = bio_map_kern(q, kbuf, len, gfp_mask);

	if (IS_ERR(bio))
		return PTR_ERR(bio);

	bio->bi_opf &= ~REQ_OP_MASK;
	bio->bi_opf |= req_op(rq);

	if (do_copy)
		rq->rq_flags |= RQF_COPY_USER;

	ret = blk_rq_append_bio(rq, bio);
	if (unlikely(ret)) {
		/* request is too big */
		bio_put(bio);
		return ret;
	}

	return 0;
}
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Jens Axboe
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45.41%
1
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FUJITA Tomonori
59
28.50%
3
30.00%
James Bottomley
24
11.59%
1
10.00%
Christoph Hellwig
15
7.25%
2
20.00%
Namhyung Kim
11
5.31%
1
10.00%
Martin K. Petersen
3
1.45%
1
10.00%
Michael Christie
1
0.48%
1
10.00%
Total
207
100.00%
10
100.00%


EXPORT_SYMBOL(blk_rq_map_kern);
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366
37.85%
2
6.25%
Christoph Hellwig
347
35.88%
7
21.88%
FUJITA Tomonori
101
10.44%
7
21.88%
Al Viro
61
6.31%
3
9.38%
Kent Overstreet
26
2.69%
2
6.25%
James Bottomley
24
2.48%
1
3.12%
Linus Torvalds
13
1.34%
1
3.12%
Namhyung Kim
11
1.14%
1
3.12%
Sagi Grimberg
5
0.52%
1
3.12%
Ingo Molnar
3
0.31%
1
3.12%
Xiaotian Feng
3
0.31%
1
3.12%
Martin K. Petersen
3
0.31%
1
3.12%
Michael Christie
1
0.10%
1
3.12%
Tejun Heo
1
0.10%
1
3.12%
Randy Dunlap
1
0.10%
1
3.12%
Greg Kroah-Hartman
1
0.10%
1
3.12%
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32
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