mirror of
https://github.com/AuxXxilium/linux_dsm_epyc7002.git
synced 2024-12-15 09:06:52 +07:00
a0763b27bf
The tape drivers (and the sg driver in a special case that doesn't matter
here) use the null_mapped flag to tell blk_rq_map_user to not copy around
any data into or out of the bounce buffers. blk_rq_map_user_iov never
got that treatment, which didn't matter until I refactored blk_rq_map_user
to be implemented in terms of blk_rq_map_user_iov.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Fixes: ddad8dd0a1
("block: use blk_rq_map_user_iov to implement blk_rq_map_user")
Signed-off-by: Jens Axboe <axboe@fb.com>
221 lines
5.2 KiB
C
221 lines
5.2 KiB
C
/*
|
|
* Functions related to mapping data to requests
|
|
*/
|
|
#include <linux/kernel.h>
|
|
#include <linux/module.h>
|
|
#include <linux/bio.h>
|
|
#include <linux/blkdev.h>
|
|
#include <linux/uio.h>
|
|
|
|
#include "blk.h"
|
|
|
|
int blk_rq_append_bio(struct request_queue *q, struct request *rq,
|
|
struct bio *bio)
|
|
{
|
|
if (!rq->bio)
|
|
blk_rq_bio_prep(q, rq, bio);
|
|
else if (!ll_back_merge_fn(q, rq, bio))
|
|
return -EINVAL;
|
|
else {
|
|
rq->biotail->bi_next = bio;
|
|
rq->biotail = bio;
|
|
|
|
rq->__data_len += bio->bi_iter.bi_size;
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
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;
|
|
}
|
|
|
|
/**
|
|
* blk_rq_map_user_iov - map user data to a request, for REQ_TYPE_BLOCK_PC usage
|
|
* @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)
|
|
{
|
|
struct bio *bio;
|
|
int unaligned = 0;
|
|
struct iov_iter i;
|
|
struct iovec iov;
|
|
|
|
if (!iter || !iter->count)
|
|
return -EINVAL;
|
|
|
|
iov_for_each(iov, i, *iter) {
|
|
unsigned long uaddr = (unsigned long) iov.iov_base;
|
|
|
|
if (!iov.iov_len)
|
|
return -EINVAL;
|
|
|
|
/*
|
|
* Keep going so we check length of all segments
|
|
*/
|
|
if (uaddr & queue_dma_alignment(q))
|
|
unaligned = 1;
|
|
}
|
|
|
|
if (unaligned || (q->dma_pad_mask & iter->count) || map_data)
|
|
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);
|
|
|
|
if (map_data && map_data->null_mapped)
|
|
bio->bi_flags |= (1 << BIO_NULL_MAPPED);
|
|
|
|
if (bio->bi_iter.bi_size != iter->count) {
|
|
/*
|
|
* Grab an extra reference to this bio, as bio_unmap_user()
|
|
* expects to be able to drop it twice as it happens on the
|
|
* normal IO completion path
|
|
*/
|
|
bio_get(bio);
|
|
bio_endio(bio, 0);
|
|
__blk_rq_unmap_user(bio);
|
|
return -EINVAL;
|
|
}
|
|
|
|
if (!bio_flagged(bio, BIO_USER_MAPPED))
|
|
rq->cmd_flags |= REQ_COPY_USER;
|
|
|
|
blk_queue_bounce(q, &bio);
|
|
bio_get(bio);
|
|
blk_rq_bio_prep(q, rq, bio);
|
|
return 0;
|
|
}
|
|
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;
|
|
|
|
iov.iov_base = ubuf;
|
|
iov.iov_len = len;
|
|
iov_iter_init(&i, rq_data_dir(rq), &iov, 1, len);
|
|
|
|
return blk_rq_map_user_iov(q, rq, map_data, &i, gfp_mask);
|
|
}
|
|
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;
|
|
}
|
|
EXPORT_SYMBOL(blk_rq_unmap_user);
|
|
|
|
/**
|
|
* blk_rq_map_kern - map kernel data to a request, for REQ_TYPE_BLOCK_PC usage
|
|
* @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);
|
|
|
|
if (!reading)
|
|
bio->bi_rw |= REQ_WRITE;
|
|
|
|
if (do_copy)
|
|
rq->cmd_flags |= REQ_COPY_USER;
|
|
|
|
ret = blk_rq_append_bio(q, rq, bio);
|
|
if (unlikely(ret)) {
|
|
/* request is too big */
|
|
bio_put(bio);
|
|
return ret;
|
|
}
|
|
|
|
blk_queue_bounce(q, &rq->bio);
|
|
return 0;
|
|
}
|
|
EXPORT_SYMBOL(blk_rq_map_kern);
|