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block: rewrite and split __bio_copy_iov()

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Rewrite __bio_copy_iov using the copy_page_{from,to}_iter helpers, and
split it into two simpler functions.

This commit should contain only literal replacements, without
functional changes.

Cc: Kent Overstreet <kmo@daterainc.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Dongsu Park <dongsu.park@profitbricks.com>
[hch: removed the __bio_copy_iov wrapper]
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Ming Lei <tom.leiming@gmail.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
This commit is contained in:
Dongsu Park 2015-01-18 16:16:34 +01:00 committed by Jens Axboe
parent 37f19e57a0
commit 9124d3fe21
1 changed files with 54 additions and 32 deletions
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86
block/bio.c
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@ -1036,43 +1036,66 @@ static struct bio_map_data *bio_alloc_map_data(unsigned int iov_count,
sizeof(struct iovec) * iov_count, gfp_mask);
}
static int __bio_copy_iov(struct bio *bio, const struct iov_iter *iter,
int to_user, int from_user)
/**
* bio_copy_from_iter - copy all pages from iov_iter to bio
* @bio: The &struct bio which describes the I/O as destination
* @iter: iov_iter as source
*
* Copy all pages from iov_iter to bio.
* Returns 0 on success, or error on failure.
*/
static int bio_copy_from_iter(struct bio *bio, struct iov_iter iter)
{
int ret = 0, i;
int i;
struct bio_vec *bvec;
struct iov_iter iov_iter = *iter;
bio_for_each_segment_all(bvec, bio, i) {
char *bv_addr = page_address(bvec->bv_page);
unsigned int bv_len = bvec->bv_len;
ssize_t ret;
while (bv_len && iov_iter.count) {
struct iovec iov = iov_iter_iovec(&iov_iter);
unsigned int bytes = min_t(unsigned int, bv_len,
iov.iov_len);
ret = copy_page_from_iter(bvec->bv_page,
bvec->bv_offset,
bvec->bv_len,
&iter);
if (!ret) {
if (to_user)
ret = copy_to_user(iov.iov_base,
bv_addr, bytes);
if (!iov_iter_count(&iter))
break;
if (from_user)
ret = copy_from_user(bv_addr,
iov.iov_base,
bytes);
if (ret)
ret = -EFAULT;
}
bv_len -= bytes;
bv_addr += bytes;
iov_iter_advance(&iov_iter, bytes);
}
if (ret < bvec->bv_len)
return -EFAULT;
}
return ret;
return 0;
}
/**
* bio_copy_to_iter - copy all pages from bio to iov_iter
* @bio: The &struct bio which describes the I/O as source
* @iter: iov_iter as destination
*
* Copy all pages from bio to iov_iter.
* Returns 0 on success, or error on failure.
*/
static int bio_copy_to_iter(struct bio *bio, struct iov_iter iter)
{
int i;
struct bio_vec *bvec;
bio_for_each_segment_all(bvec, bio, i) {
ssize_t ret;
ret = copy_page_to_iter(bvec->bv_page,
bvec->bv_offset,
bvec->bv_len,
&iter);
if (!iov_iter_count(&iter))
break;
if (ret < bvec->bv_len)
return -EFAULT;
}
return 0;
}
static void bio_free_pages(struct bio *bio)
@ -1101,9 +1124,8 @@ int bio_uncopy_user(struct bio *bio)
* if we're in a workqueue, the request is orphaned, so
* don't copy into a random user address space, just free.
*/
if (current->mm)
ret = __bio_copy_iov(bio, &bmd->iter,
bio_data_dir(bio) == READ, 0);
if (current->mm && bio_data_dir(bio) == READ)
ret = bio_copy_to_iter(bio, bmd->iter);
if (bmd->is_our_pages)
bio_free_pages(bio);
}
@ -1228,7 +1250,7 @@ struct bio *bio_copy_user_iov(struct request_queue *q,
*/
if (((iter->type & WRITE) && (!map_data || !map_data->null_mapped)) ||
(map_data && map_data->from_user)) {
ret = __bio_copy_iov(bio, iter, 0, 1);
ret = bio_copy_from_iter(bio, *iter);
if (ret)
goto cleanup;
}