mirror of
https://github.com/torvalds/linux.git
synced 2024-11-22 20:22:09 +00:00
f5f82cd187
Move netfs_extract_iter_to_sg() to lib/scatterlist.c as it's going to be used by more than just network filesystems (AF_ALG, for example). Signed-off-by: David Howells <dhowells@redhat.com> cc: Jeff Layton <jlayton@kernel.org> cc: Steve French <sfrench@samba.org> cc: Shyam Prasad N <nspmangalore@gmail.com> cc: Rohith Surabattula <rohiths.msft@gmail.com> cc: Jens Axboe <axboe@kernel.dk> cc: Herbert Xu <herbert@gondor.apana.org.au> cc: "David S. Miller" <davem@davemloft.net> cc: Eric Dumazet <edumazet@google.com> cc: Jakub Kicinski <kuba@kernel.org> cc: Paolo Abeni <pabeni@redhat.com> cc: Matthew Wilcox <willy@infradead.org> cc: linux-crypto@vger.kernel.org cc: linux-cachefs@redhat.com cc: linux-cifs@vger.kernel.org cc: linux-fsdevel@vger.kernel.org cc: netdev@vger.kernel.org Signed-off-by: Paolo Abeni <pabeni@redhat.com>
104 lines
2.9 KiB
C
104 lines
2.9 KiB
C
// SPDX-License-Identifier: GPL-2.0-or-later
|
|
/* Iterator helpers.
|
|
*
|
|
* Copyright (C) 2022 Red Hat, Inc. All Rights Reserved.
|
|
* Written by David Howells (dhowells@redhat.com)
|
|
*/
|
|
|
|
#include <linux/export.h>
|
|
#include <linux/slab.h>
|
|
#include <linux/mm.h>
|
|
#include <linux/uio.h>
|
|
#include <linux/scatterlist.h>
|
|
#include <linux/netfs.h>
|
|
#include "internal.h"
|
|
|
|
/**
|
|
* netfs_extract_user_iter - Extract the pages from a user iterator into a bvec
|
|
* @orig: The original iterator
|
|
* @orig_len: The amount of iterator to copy
|
|
* @new: The iterator to be set up
|
|
* @extraction_flags: Flags to qualify the request
|
|
*
|
|
* Extract the page fragments from the given amount of the source iterator and
|
|
* build up a second iterator that refers to all of those bits. This allows
|
|
* the original iterator to disposed of.
|
|
*
|
|
* @extraction_flags can have ITER_ALLOW_P2PDMA set to request peer-to-peer DMA be
|
|
* allowed on the pages extracted.
|
|
*
|
|
* On success, the number of elements in the bvec is returned, the original
|
|
* iterator will have been advanced by the amount extracted.
|
|
*
|
|
* The iov_iter_extract_mode() function should be used to query how cleanup
|
|
* should be performed.
|
|
*/
|
|
ssize_t netfs_extract_user_iter(struct iov_iter *orig, size_t orig_len,
|
|
struct iov_iter *new,
|
|
iov_iter_extraction_t extraction_flags)
|
|
{
|
|
struct bio_vec *bv = NULL;
|
|
struct page **pages;
|
|
unsigned int cur_npages;
|
|
unsigned int max_pages;
|
|
unsigned int npages = 0;
|
|
unsigned int i;
|
|
ssize_t ret;
|
|
size_t count = orig_len, offset, len;
|
|
size_t bv_size, pg_size;
|
|
|
|
if (WARN_ON_ONCE(!iter_is_ubuf(orig) && !iter_is_iovec(orig)))
|
|
return -EIO;
|
|
|
|
max_pages = iov_iter_npages(orig, INT_MAX);
|
|
bv_size = array_size(max_pages, sizeof(*bv));
|
|
bv = kvmalloc(bv_size, GFP_KERNEL);
|
|
if (!bv)
|
|
return -ENOMEM;
|
|
|
|
/* Put the page list at the end of the bvec list storage. bvec
|
|
* elements are larger than page pointers, so as long as we work
|
|
* 0->last, we should be fine.
|
|
*/
|
|
pg_size = array_size(max_pages, sizeof(*pages));
|
|
pages = (void *)bv + bv_size - pg_size;
|
|
|
|
while (count && npages < max_pages) {
|
|
ret = iov_iter_extract_pages(orig, &pages, count,
|
|
max_pages - npages, extraction_flags,
|
|
&offset);
|
|
if (ret < 0) {
|
|
pr_err("Couldn't get user pages (rc=%zd)\n", ret);
|
|
break;
|
|
}
|
|
|
|
if (ret > count) {
|
|
pr_err("get_pages rc=%zd more than %zu\n", ret, count);
|
|
break;
|
|
}
|
|
|
|
count -= ret;
|
|
ret += offset;
|
|
cur_npages = DIV_ROUND_UP(ret, PAGE_SIZE);
|
|
|
|
if (npages + cur_npages > max_pages) {
|
|
pr_err("Out of bvec array capacity (%u vs %u)\n",
|
|
npages + cur_npages, max_pages);
|
|
break;
|
|
}
|
|
|
|
for (i = 0; i < cur_npages; i++) {
|
|
len = ret > PAGE_SIZE ? PAGE_SIZE : ret;
|
|
bvec_set_page(bv + npages + i, *pages++, len - offset, offset);
|
|
ret -= len;
|
|
offset = 0;
|
|
}
|
|
|
|
npages += cur_npages;
|
|
}
|
|
|
|
iov_iter_bvec(new, orig->data_source, bv, npages, orig_len - count);
|
|
return npages;
|
|
}
|
|
EXPORT_SYMBOL_GPL(netfs_extract_user_iter);
|