cregit-Linux how code gets into the kernel

Release 4.12 block/blk-map.c

Directory: block
 * 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) { 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; }


Jens Axboe7286.75%125.00%
Christoph Hellwig89.64%125.00%
Kent Overstreet22.41%125.00%
Tejun Heo11.20%125.00%

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); 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; blk_queue_bounce(q, &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 */ bio_get(bio); ret = blk_rq_append_bio(rq, bio); if (ret) { bio_endio(bio); __blk_rq_unmap_user(orig_bio); bio_put(bio); return ret; } return 0; }


Christoph Hellwig199100.00%2100.00%

/** * 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; 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; }


Christoph Hellwig6532.02%320.00%
Jens Axboe4120.20%213.33%
Al Viro3818.72%213.33%
FUJITA Tomonori3517.24%426.67%
Linus Torvalds136.40%16.67%
Sagi Grimberg52.46%16.67%
Kent Overstreet31.48%16.67%
Xiaotian Feng31.48%16.67%

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; 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; } blk_queue_bounce(q, &rq->bio); return 0; }


Jens Axboe10447.93%110.00%
FUJITA Tomonori5927.19%330.00%
James Bottomley2411.06%110.00%
Christoph Hellwig156.91%220.00%
Namhyung Kim115.07%110.00%
Martin K. Petersen31.38%110.00%
Michael Christie10.46%110.00%


Overall Contributors

Jens Axboe37638.60%26.67%
Christoph Hellwig34535.42%620.00%
FUJITA Tomonori10110.37%723.33%
Al Viro616.26%310.00%
Kent Overstreet262.67%26.67%
James Bottomley242.46%13.33%
Linus Torvalds131.33%13.33%
Namhyung Kim111.13%13.33%
Sagi Grimberg50.51%13.33%
Martin K. Petersen30.31%13.33%
Xiaotian Feng30.31%13.33%
Ingo Molnar30.31%13.33%
Michael Christie10.10%13.33%
Tejun Heo10.10%13.33%
Randy Dunlap10.10%13.33%
Directory: block
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