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Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni , Willem de Bruijn , David Ahern , Matthew Wilcox , Jens Axboe , linux-crypto@vger.kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, Jeff Layton , Steve French , Shyam Prasad N , Rohith Surabattula , linux-cachefs@redhat.com, linux-cifs@vger.kernel.org, linux-fsdevel@vger.kernel.org Subject: [PATCH net-next v2 04/10] Move netfs_extract_iter_to_sg() to lib/scatterlist.c Date: Tue, 30 May 2023 15:16:28 +0100 Message-ID: <20230530141635.136968-5-dhowells@redhat.com> In-Reply-To: <20230530141635.136968-1-dhowells@redhat.com> References: <20230530141635.136968-1-dhowells@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 3.1 on 10.11.54.2 X-Rspamd-Queue-Id: 4165B180015 X-Rspam-User: X-Rspamd-Server: rspam11 X-Stat-Signature: 64zj6ukhkbwcyzik7cm9ogdniz9xfdfy X-HE-Tag: 1685456248-598276 X-HE-Meta: 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 bgHiTmej 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 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: 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 --- fs/netfs/iterator.c | 267 ----------------------------------------- include/linux/netfs.h | 4 - include/linux/uio.h | 5 + lib/scatterlist.c | 269 ++++++++++++++++++++++++++++++++++++++++++ 4 files changed, 274 insertions(+), 271 deletions(-) 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); diff --git a/include/linux/netfs.h b/include/linux/netfs.h index 55e201c3a841..b11a84f6c32b 100644 --- a/include/linux/netfs.h +++ b/include/linux/netfs.h @@ -300,10 +300,6 @@ void netfs_stats_show(struct seq_file *); 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 sg_table; -ssize_t extract_iter_to_sg(struct iov_iter *iter, size_t len, - struct sg_table *sgtable, unsigned int sg_max, - iov_iter_extraction_t extraction_flags); /** * netfs_inode - Get the netfs inode context from the inode diff --git a/include/linux/uio.h b/include/linux/uio.h index 044c1d8c230c..0ccb983cf645 100644 --- a/include/linux/uio.h +++ b/include/linux/uio.h @@ -433,4 +433,9 @@ static inline bool iov_iter_extract_will_pin(const struct iov_iter *iter) return user_backed_iter(iter); } +struct sg_table; +ssize_t extract_iter_to_sg(struct iov_iter *iter, size_t len, + struct sg_table *sgtable, unsigned int sg_max, + iov_iter_extraction_t extraction_flags); + #endif diff --git a/lib/scatterlist.c b/lib/scatterlist.c index 8d7519a8f308..e97d7060329e 100644 --- a/lib/scatterlist.c +++ b/lib/scatterlist.c @@ -9,6 +9,8 @@ #include #include #include +#include +#include /** * sg_next - return the next scatterlist entry in a list @@ -1095,3 +1097,270 @@ size_t sg_zero_buffer(struct scatterlist *sgl, unsigned int nents, return offset; } EXPORT_SYMBOL(sg_zero_buffer); + +/* + * 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);