cregit-Linux how code gets into the kernel

Release 4.18 block/blk-map.c

Directory: block
// 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 if the bio can be merged
 * into the request based on the driver constraints.

int blk_rq_append_bio(struct request *rq, struct bio **bio) { struct bio *orig_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)) { if (orig_bio != *bio) { bio_put(*bio); *bio = orig_bio; } return -EINVAL; } rq->biotail->bi_next = *bio; rq->biotail = *bio; rq->__data_len += (*bio)->bi_iter.bi_size; } return 0; }


Jens Axboe11084.62%233.33%
Christoph Hellwig1713.08%233.33%
Kent Overstreet21.54%116.67%
Tejun Heo10.77%116.67%

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; }


Jens Axboe47100.00%1100.00%

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); 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); if (ret) { __blk_rq_unmap_user(orig_bio); return ret; } bio_get(bio); return 0; }


Christoph Hellwig13695.77%375.00%
Jens Axboe64.23%125.00%

/** * 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 = -EINVAL; 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 ret; }


Christoph Hellwig6330.73%318.75%
Jens Axboe4120.00%212.50%
Al Viro3818.54%212.50%
FUJITA Tomonori3517.07%425.00%
Linus Torvalds136.34%16.25%
Sagi Grimberg52.44%16.25%
Douglas Gilbert41.95%16.25%
Kent Overstreet31.46%16.25%
Xiaotian Feng31.46%16.25%

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); }


Christoph Hellwig4551.14%133.33%
Al Viro2326.14%133.33%
Kent Overstreet2022.73%133.33%

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; }


Jens Axboe86100.00%1100.00%

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, *orig_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; orig_bio = bio; ret = blk_rq_append_bio(rq, &bio); if (unlikely(ret)) { /* request is too big */ bio_put(orig_bio); return ret; } return 0; }


Jens Axboe10347.91%218.18%
FUJITA Tomonori5927.44%327.27%
James Bottomley2310.70%19.09%
Christoph Hellwig156.98%218.18%
Namhyung Kim115.12%19.09%
Martin K. Petersen31.40%19.09%
Michael Christie10.47%19.09%


Overall Contributors

Jens Axboe42043.52%38.82%
Christoph Hellwig28829.84%720.59%
FUJITA Tomonori10110.47%720.59%
Al Viro616.32%38.82%
Kent Overstreet262.69%25.88%
James Bottomley232.38%12.94%
Linus Torvalds131.35%12.94%
Namhyung Kim111.14%12.94%
Sagi Grimberg50.52%12.94%
Douglas Gilbert40.41%12.94%
Martin K. Petersen30.31%12.94%
Xiaotian Feng30.31%12.94%
Ingo Molnar30.31%12.94%
Greg Kroah-Hartman10.10%12.94%
Randy Dunlap10.10%12.94%
Michael Christie10.10%12.94%
Tejun Heo10.10%12.94%
Directory: block
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