From f5f82cd18732d828bcd1ec308c4e8c55012e84b0 Mon Sep 17 00:00:00 2001 From: David Howells Date: Tue, 6 Jun 2023 14:08:50 +0100 Subject: Move netfs_extract_iter_to_sg() to lib/scatterlist.c 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 cc: Jeff Layton cc: Steve French cc: Shyam Prasad N cc: Rohith Surabattula cc: Jens Axboe cc: Herbert Xu cc: "David S. Miller" cc: Eric Dumazet cc: Jakub Kicinski cc: Paolo Abeni cc: Matthew Wilcox 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 --- fs/netfs/iterator.c | 267 ---------------------------------------------------- 1 file changed, 267 deletions(-) (limited to 'fs/netfs') diff --git a/fs/netfs/iterator.c b/fs/netfs/iterator.c index 9f09dc30ceb6..2ff07ba655a0 100644 --- a/fs/netfs/iterator.c +++ b/fs/netfs/iterator.c @@ -101,270 +101,3 @@ ssize_t netfs_extract_user_iter(struct iov_iter *orig, size_t orig_len, return npages; } EXPORT_SYMBOL_GPL(netfs_extract_user_iter); - -/* - * Extract and pin a list of up to sg_max pages from UBUF- or IOVEC-class - * iterators, and add them to the scatterlist. - */ -static ssize_t extract_user_to_sg(struct iov_iter *iter, - ssize_t maxsize, - struct sg_table *sgtable, - unsigned int sg_max, - iov_iter_extraction_t extraction_flags) -{ - struct scatterlist *sg = sgtable->sgl + sgtable->nents; - struct page **pages; - unsigned int npages; - ssize_t ret = 0, res; - size_t len, off; - - /* We decant the page list into the tail of the scatterlist */ - pages = (void *)sgtable->sgl + - array_size(sg_max, sizeof(struct scatterlist)); - pages -= sg_max; - - do { - res = iov_iter_extract_pages(iter, &pages, maxsize, sg_max, - extraction_flags, &off); - if (res < 0) - goto failed; - - len = res; - maxsize -= len; - ret += len; - npages = DIV_ROUND_UP(off + len, PAGE_SIZE); - sg_max -= npages; - - for (; npages > 0; npages--) { - struct page *page = *pages; - size_t seg = min_t(size_t, PAGE_SIZE - off, len); - - *pages++ = NULL; - sg_set_page(sg, page, seg, off); - sgtable->nents++; - sg++; - len -= seg; - off = 0; - } - } while (maxsize > 0 && sg_max > 0); - - return ret; - -failed: - while (sgtable->nents > sgtable->orig_nents) - put_page(sg_page(&sgtable->sgl[--sgtable->nents])); - return res; -} - -/* - * Extract up to sg_max pages from a BVEC-type iterator and add them to the - * scatterlist. The pages are not pinned. - */ -static ssize_t extract_bvec_to_sg(struct iov_iter *iter, - ssize_t maxsize, - struct sg_table *sgtable, - unsigned int sg_max, - iov_iter_extraction_t extraction_flags) -{ - const struct bio_vec *bv = iter->bvec; - struct scatterlist *sg = sgtable->sgl + sgtable->nents; - unsigned long start = iter->iov_offset; - unsigned int i; - ssize_t ret = 0; - - for (i = 0; i < iter->nr_segs; i++) { - size_t off, len; - - len = bv[i].bv_len; - if (start >= len) { - start -= len; - continue; - } - - len = min_t(size_t, maxsize, len - start); - off = bv[i].bv_offset + start; - - sg_set_page(sg, bv[i].bv_page, len, off); - sgtable->nents++; - sg++; - sg_max--; - - ret += len; - maxsize -= len; - if (maxsize <= 0 || sg_max == 0) - break; - start = 0; - } - - if (ret > 0) - iov_iter_advance(iter, ret); - return ret; -} - -/* - * Extract up to sg_max pages from a KVEC-type iterator and add them to the - * scatterlist. This can deal with vmalloc'd buffers as well as kmalloc'd or - * static buffers. The pages are not pinned. - */ -static ssize_t extract_kvec_to_sg(struct iov_iter *iter, - ssize_t maxsize, - struct sg_table *sgtable, - unsigned int sg_max, - iov_iter_extraction_t extraction_flags) -{ - const struct kvec *kv = iter->kvec; - struct scatterlist *sg = sgtable->sgl + sgtable->nents; - unsigned long start = iter->iov_offset; - unsigned int i; - ssize_t ret = 0; - - for (i = 0; i < iter->nr_segs; i++) { - struct page *page; - unsigned long kaddr; - size_t off, len, seg; - - len = kv[i].iov_len; - if (start >= len) { - start -= len; - continue; - } - - kaddr = (unsigned long)kv[i].iov_base + start; - off = kaddr & ~PAGE_MASK; - len = min_t(size_t, maxsize, len - start); - kaddr &= PAGE_MASK; - - maxsize -= len; - ret += len; - do { - seg = min_t(size_t, len, PAGE_SIZE - off); - if (is_vmalloc_or_module_addr((void *)kaddr)) - page = vmalloc_to_page((void *)kaddr); - else - page = virt_to_page(kaddr); - - sg_set_page(sg, page, len, off); - sgtable->nents++; - sg++; - sg_max--; - - len -= seg; - kaddr += PAGE_SIZE; - off = 0; - } while (len > 0 && sg_max > 0); - - if (maxsize <= 0 || sg_max == 0) - break; - start = 0; - } - - if (ret > 0) - iov_iter_advance(iter, ret); - return ret; -} - -/* - * Extract up to sg_max folios from an XARRAY-type iterator and add them to - * the scatterlist. The pages are not pinned. - */ -static ssize_t extract_xarray_to_sg(struct iov_iter *iter, - ssize_t maxsize, - struct sg_table *sgtable, - unsigned int sg_max, - iov_iter_extraction_t extraction_flags) -{ - struct scatterlist *sg = sgtable->sgl + sgtable->nents; - struct xarray *xa = iter->xarray; - struct folio *folio; - loff_t start = iter->xarray_start + iter->iov_offset; - pgoff_t index = start / PAGE_SIZE; - ssize_t ret = 0; - size_t offset, len; - XA_STATE(xas, xa, index); - - rcu_read_lock(); - - xas_for_each(&xas, folio, ULONG_MAX) { - if (xas_retry(&xas, folio)) - continue; - if (WARN_ON(xa_is_value(folio))) - break; - if (WARN_ON(folio_test_hugetlb(folio))) - break; - - offset = offset_in_folio(folio, start); - len = min_t(size_t, maxsize, folio_size(folio) - offset); - - sg_set_page(sg, folio_page(folio, 0), len, offset); - sgtable->nents++; - sg++; - sg_max--; - - maxsize -= len; - ret += len; - if (maxsize <= 0 || sg_max == 0) - break; - } - - rcu_read_unlock(); - if (ret > 0) - iov_iter_advance(iter, ret); - return ret; -} - -/** - * extract_iter_to_sg - Extract pages from an iterator and add to an sglist - * @iter: The iterator to extract from - * @maxsize: The amount of iterator to copy - * @sgtable: The scatterlist table to fill in - * @sg_max: Maximum number of elements in @sgtable that may be filled - * @extraction_flags: Flags to qualify the request - * - * Extract the page fragments from the given amount of the source iterator and - * add them to a scatterlist that refers to all of those bits, to a maximum - * addition of @sg_max elements. - * - * The pages referred to by UBUF- and IOVEC-type iterators are extracted and - * pinned; BVEC-, KVEC- and XARRAY-type are extracted but aren't pinned; PIPE- - * and DISCARD-type are not supported. - * - * No end mark is placed on the scatterlist; that's left to the caller. - * - * @extraction_flags can have ITER_ALLOW_P2PDMA set to request peer-to-peer DMA - * be allowed on the pages extracted. - * - * If successful, @sgtable->nents is updated to include the number of elements - * added and the number of bytes added is returned. @sgtable->orig_nents is - * left unaltered. - * - * The iov_iter_extract_mode() function should be used to query how cleanup - * should be performed. - */ -ssize_t extract_iter_to_sg(struct iov_iter *iter, size_t maxsize, - struct sg_table *sgtable, unsigned int sg_max, - iov_iter_extraction_t extraction_flags) -{ - if (maxsize == 0) - return 0; - - switch (iov_iter_type(iter)) { - case ITER_UBUF: - case ITER_IOVEC: - return extract_user_to_sg(iter, maxsize, sgtable, sg_max, - extraction_flags); - case ITER_BVEC: - return extract_bvec_to_sg(iter, maxsize, sgtable, sg_max, - extraction_flags); - case ITER_KVEC: - return extract_kvec_to_sg(iter, maxsize, sgtable, sg_max, - extraction_flags); - case ITER_XARRAY: - return extract_xarray_to_sg(iter, maxsize, sgtable, sg_max, - extraction_flags); - default: - pr_err("%s(%u) unsupported\n", __func__, iov_iter_type(iter)); - WARN_ON_ONCE(1); - return -EIO; - } -} -EXPORT_SYMBOL_GPL(extract_iter_to_sg); -- cgit v1.2.3-58-ga151