[PATCH net-next 0/8] crypto, splice, net: Make AF_ALG handle sendmsg(MSG_SPLICE_PAGES)

[PATCH net-next 0/8] crypto, splice, net: Make AF_ALG handle sendmsg(MSG_SPLICE_PAGES)

[David Howells]

Here's the fourth tranche of patches towards providing a MSG_SPLICE_PAGES
internal sendmsg flag that is intended to replace the ->sendpage() op with
calls to sendmsg().  MSG_SPLICE_PAGES is a hint that tells the protocol
that it should splice the pages supplied if it can.

This set consists of the following parts:

 (1) Move netfs_extract_iter_to_sg() to somewhere more general and rename
     it to drop the "netfs" prefix.  We use this to extract directly from
     an iterator into a scatterlist.

 (2) Make AF_ALG use iov_iter_extract_pages().  This has the additional
     effect of pinning pages obtained from userspace rather than taking
     refs on them.  Pages from kernel-backed iterators would not be pinned,
     but AF_ALG isn't really meant for use by kernel services.

 (3) Change AF_ALG still further to use extract_iter_to_sg().

 (4) Make af_alg_sendmsg() support MSG_SPLICE_PAGES support and make
     af_alg_sendpage() just a wrapper around sendmsg().  This has to take
     refs on the pages pinned for the moment.

 (5) Make hash_sendmsg() support MSG_SPLICE_PAGES by simply ignoring it.
     hash_sendpage() is left untouched to be removed later, after the
     splice core has been changed to call sendmsg().

I've pushed the patches here also:

	https://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-fs.git/log/?h=sendpage-4

David

Link: https://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next.git/commit/?id=51c78a4d532efe9543a4df019ff405f05c6157f6 # part 1

David Howells (8):
  Move netfs_extract_iter_to_sg() to lib/scatterlist.c
  Drop the netfs_ prefix from netfs_extract_iter_to_sg()
  crypto: af_alg: Pin pages rather than ref'ing if appropriate
  crypto: af_alg: Use extract_iter_to_sg() to create scatterlists
  crypto: af_alg: Indent the loop in af_alg_sendmsg()
  crypto: af_alg: Support MSG_SPLICE_PAGES
  crypto: af_alg: Convert af_alg_sendpage() to use MSG_SPLICE_PAGES
  crypto: af_alg/hash: Support MSG_SPLICE_PAGES

 crypto/af_alg.c             | 183 +++++++++++-------------
 crypto/algif_aead.c         |  34 ++---
 crypto/algif_hash.c         | 110 +++++++++------
 crypto/algif_skcipher.c     |  10 +-
 fs/cifs/smb2ops.c           |   4 +-
 fs/cifs/smbdirect.c         |   2 +-
 fs/netfs/iterator.c         | 266 -----------------------------------
 include/crypto/if_alg.h     |   7 +-
 include/linux/netfs.h       |   4 -
 include/linux/scatterlist.h |   1 +
 include/linux/uio.h         |   5 +
 lib/scatterlist.c           | 267 ++++++++++++++++++++++++++++++++++++
 12 files changed, 449 insertions(+), 444 deletions(-)

[PATCH net-next 1/8] Move netfs_extract_iter_to_sg() to lib/scatterlist.c

[David Howells]

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: 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         | 266 -----------------------------------
 include/linux/netfs.h       |   4 -
 include/linux/scatterlist.h |   1 +
 include/linux/uio.h         |   5 +
 lib/scatterlist.c           | 267 ++++++++++++++++++++++++++++++++++++
 5 files changed, 273 insertions(+), 270 deletions(-)

diff --git a/fs/netfs/iterator.c b/fs/netfs/iterator.c
index 8a4c86687429..2ff07ba655a0 100644
--- a/fs/netfs/iterator.c
+++ b/fs/netfs/iterator.c
@@ -101,269 +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 netfs_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 netfs_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 netfs_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 netfs_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;
-}
-
-/**
- * netfs_extract_iter_to_sg - Extract pages from an iterator and add ot 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 successul, @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 netfs_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 netfs_extract_user_to_sg(iter, maxsize, sgtable, sg_max,
-						extraction_flags);
-	case ITER_BVEC:
-		return netfs_extract_bvec_to_sg(iter, maxsize, sgtable, sg_max,
-						extraction_flags);
-	case ITER_KVEC:
-		return netfs_extract_kvec_to_sg(iter, maxsize, sgtable, sg_max,
-						extraction_flags);
-	case ITER_XARRAY:
-		return netfs_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(netfs_extract_iter_to_sg);
diff --git a/include/linux/netfs.h b/include/linux/netfs.h
index a1f3522daa69..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 netfs_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/scatterlist.h b/include/linux/scatterlist.h
index 375a5e90d86a..9e6a4457f4fc 100644
--- a/include/linux/scatterlist.h
+++ b/include/linux/scatterlist.h
@@ -6,6 +6,7 @@
 #include <linux/types.h>
 #include <linux/bug.h>
 #include <linux/mm.h>
+#include <linux/bvec.h>
 #include <asm/io.h>
 
 struct scatterlist {
diff --git a/include/linux/uio.h b/include/linux/uio.h
index 044c1d8c230c..09b8b107956e 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 netfs_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..31ef86e6a33a 100644
--- a/lib/scatterlist.c
+++ b/lib/scatterlist.c
@@ -9,6 +9,7 @@
 #include <linux/scatterlist.h>
 #include <linux/highmem.h>
 #include <linux/kmemleak.h>
+#include <linux/uio.h>
 
 /**
  * sg_next - return the next scatterlist entry in a list
@@ -1095,3 +1096,269 @@ 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 netfs_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 netfs_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 netfs_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 netfs_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;
+}
+
+/**
+ * netfs_extract_iter_to_sg - Extract pages from an iterator and add ot 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 successul, @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 netfs_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 netfs_extract_user_to_sg(iter, maxsize, sgtable, sg_max,
+						extraction_flags);
+	case ITER_BVEC:
+		return netfs_extract_bvec_to_sg(iter, maxsize, sgtable, sg_max,
+						extraction_flags);
+	case ITER_KVEC:
+		return netfs_extract_kvec_to_sg(iter, maxsize, sgtable, sg_max,
+						extraction_flags);
+	case ITER_XARRAY:
+		return netfs_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(netfs_extract_iter_to_sg);

[PATCH net-next 2/8] Drop the netfs_ prefix from netfs_extract_iter_to_sg()

[David Howells]

Rename netfs_extract_iter_to_sg() and its auxiliary functions to drop the
netfs_ prefix.

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: 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/cifs/smb2ops.c   |  4 +--
 fs/cifs/smbdirect.c |  2 +-
 include/linux/uio.h |  6 ++---
 lib/scatterlist.c   | 66 ++++++++++++++++++++++-----------------------
 4 files changed, 39 insertions(+), 39 deletions(-)

diff --git a/fs/cifs/smb2ops.c b/fs/cifs/smb2ops.c
index a295e4c2d54e..196bc49e73b8 100644
--- a/fs/cifs/smb2ops.c
+++ b/fs/cifs/smb2ops.c
@@ -4335,8 +4335,8 @@ static void *smb2_get_aead_req(struct crypto_aead *tfm, struct smb_rqst *rqst,
 		}
 		sgtable.orig_nents = sgtable.nents;
 
-		rc = netfs_extract_iter_to_sg(iter, count, &sgtable,
-					      num_sgs - sgtable.nents, 0);
+		rc = extract_iter_to_sg(iter, count, &sgtable,
+					num_sgs - sgtable.nents, 0);
 		iov_iter_revert(iter, rc);
 		sgtable.orig_nents = sgtable.nents;
 	}
diff --git a/fs/cifs/smbdirect.c b/fs/cifs/smbdirect.c
index 0362ebd4fa0f..223e17c16b60 100644
--- a/fs/cifs/smbdirect.c
+++ b/fs/cifs/smbdirect.c
@@ -2227,7 +2227,7 @@ static int smbd_iter_to_mr(struct smbd_connection *info,
 
 	memset(sgt->sgl, 0, max_sg * sizeof(struct scatterlist));
 
-	ret = netfs_extract_iter_to_sg(iter, iov_iter_count(iter), sgt, max_sg, 0);
+	ret = extract_iter_to_sg(iter, iov_iter_count(iter), sgt, max_sg, 0);
 	WARN_ON(ret < 0);
 	if (sgt->nents > 0)
 		sg_mark_end(&sgt->sgl[sgt->nents - 1]);
diff --git a/include/linux/uio.h b/include/linux/uio.h
index 09b8b107956e..0ccb983cf645 100644
--- a/include/linux/uio.h
+++ b/include/linux/uio.h
@@ -434,8 +434,8 @@ static inline bool iov_iter_extract_will_pin(const struct iov_iter *iter)
 }
 
 struct sg_table;
-ssize_t netfs_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);
+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 31ef86e6a33a..8612b9deaa7e 100644
--- a/lib/scatterlist.c
+++ b/lib/scatterlist.c
@@ -1101,11 +1101,11 @@ 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 netfs_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)
+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;
@@ -1154,11 +1154,11 @@ static ssize_t netfs_extract_user_to_sg(struct iov_iter *iter,
  * 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 netfs_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)
+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;
@@ -1200,11 +1200,11 @@ static ssize_t netfs_extract_bvec_to_sg(struct iov_iter *iter,
  * scatterlist.  This can deal with vmalloc'd buffers as well as kmalloc'd or
  * static buffers.  The pages are not pinned.
  */
-static ssize_t netfs_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)
+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;
@@ -1261,11 +1261,11 @@ static ssize_t netfs_extract_kvec_to_sg(struct iov_iter *iter,
  * 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 netfs_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)
+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;
@@ -1307,7 +1307,7 @@ static ssize_t netfs_extract_xarray_to_sg(struct iov_iter *iter,
 }
 
 /**
- * netfs_extract_iter_to_sg - Extract pages from an iterator and add ot an sglist
+ * extract_iter_to_sg - Extract pages from an iterator and add ot an sglist
  * @iter: The iterator to extract from
  * @maxsize: The amount of iterator to copy
  * @sgtable: The scatterlist table to fill in
@@ -1334,9 +1334,9 @@ static ssize_t netfs_extract_xarray_to_sg(struct iov_iter *iter,
  * The iov_iter_extract_mode() function should be used to query how cleanup
  * should be performed.
  */
-ssize_t netfs_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)
+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;
@@ -1344,21 +1344,21 @@ ssize_t netfs_extract_iter_to_sg(struct iov_iter *iter, size_t maxsize,
 	switch (iov_iter_type(iter)) {
 	case ITER_UBUF:
 	case ITER_IOVEC:
-		return netfs_extract_user_to_sg(iter, maxsize, sgtable, sg_max,
-						extraction_flags);
+		return extract_user_to_sg(iter, maxsize, sgtable, sg_max,
+					  extraction_flags);
 	case ITER_BVEC:
-		return netfs_extract_bvec_to_sg(iter, maxsize, sgtable, sg_max,
-						extraction_flags);
+		return extract_bvec_to_sg(iter, maxsize, sgtable, sg_max,
+					  extraction_flags);
 	case ITER_KVEC:
-		return netfs_extract_kvec_to_sg(iter, maxsize, sgtable, sg_max,
-						extraction_flags);
+		return extract_kvec_to_sg(iter, maxsize, sgtable, sg_max,
+					  extraction_flags);
 	case ITER_XARRAY:
-		return netfs_extract_xarray_to_sg(iter, maxsize, sgtable, sg_max,
-						  extraction_flags);
+		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(netfs_extract_iter_to_sg);
+EXPORT_SYMBOL_GPL(extract_iter_to_sg);

[PATCH net-next 3/8] crypto: af_alg: Pin pages rather than ref'ing if appropriate

[David Howells]

Convert AF_ALG to use iov_iter_extract_pages() instead of
iov_iter_get_pages().  This will pin pages or leave them unaltered rather
than getting a ref on them as appropriate to the iterator.

The pages need to be pinned for DIO-read rather than having refs taken on
them to prevent VM copy-on-write from malfunctioning during a concurrent
fork() (the result of the I/O would otherwise end up only visible to the
child process and not the parent).

Signed-off-by: David Howells <dhowells@redhat.com>
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: Jens Axboe <axboe@kernel.dk>
cc: Matthew Wilcox <willy@infradead.org>
cc: linux-crypto@vger.kernel.org
cc: netdev@vger.kernel.org
---
 crypto/af_alg.c         | 10 +++++++---
 include/crypto/if_alg.h |  1 +
 2 files changed, 8 insertions(+), 3 deletions(-)

diff --git a/crypto/af_alg.c b/crypto/af_alg.c
index 5f7252a5b7b4..7caff10df643 100644
--- a/crypto/af_alg.c
+++ b/crypto/af_alg.c
@@ -533,14 +533,17 @@ static const struct net_proto_family alg_family = {
 
 int af_alg_make_sg(struct af_alg_sgl *sgl, struct iov_iter *iter, int len)
 {
+	struct page **pages = sgl->pages;
 	size_t off;
 	ssize_t n;
 	int npages, i;
 
-	n = iov_iter_get_pages2(iter, sgl->pages, len, ALG_MAX_PAGES, &off);
+	n = iov_iter_extract_pages(iter, &pages, len, ALG_MAX_PAGES, 0, &off);
 	if (n < 0)
 		return n;
 
+	sgl->need_unpin = iov_iter_extract_will_pin(iter);
+
 	npages = DIV_ROUND_UP(off + n, PAGE_SIZE);
 	if (WARN_ON(npages == 0))
 		return -EINVAL;
@@ -573,8 +576,9 @@ void af_alg_free_sg(struct af_alg_sgl *sgl)
 {
 	int i;
 
-	for (i = 0; i < sgl->npages; i++)
-		put_page(sgl->pages[i]);
+	if (sgl->need_unpin)
+		for (i = 0; i < sgl->npages; i++)
+			unpin_user_page(sgl->pages[i]);
 }
 EXPORT_SYMBOL_GPL(af_alg_free_sg);
 
diff --git a/include/crypto/if_alg.h b/include/crypto/if_alg.h
index 7e76623f9ec3..46494b33f5bc 100644
--- a/include/crypto/if_alg.h
+++ b/include/crypto/if_alg.h
@@ -59,6 +59,7 @@ struct af_alg_sgl {
 	struct scatterlist sg[ALG_MAX_PAGES + 1];
 	struct page *pages[ALG_MAX_PAGES];
 	unsigned int npages;
+	bool need_unpin;
 };
 
 /* TX SGL entry */

[PATCH net-next 4/8] crypto: af_alg: Use extract_iter_to_sg() to create scatterlists

[David Howells]

Use extract_iter_to_sg() to decant the destination iterator into a
scatterlist in af_alg_get_rsgl().  af_alg_make_sg() can then be removed.

Signed-off-by: David Howells <dhowells@redhat.com>
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: Jens Axboe <axboe@kernel.dk>
cc: Matthew Wilcox <willy@infradead.org>
cc: linux-crypto@vger.kernel.org
cc: netdev@vger.kernel.org
---
 crypto/af_alg.c         | 56 +++++++++++------------------------------
 crypto/algif_aead.c     | 12 ++++-----
 crypto/algif_hash.c     | 18 +++++++++----
 crypto/algif_skcipher.c |  2 +-
 include/crypto/if_alg.h |  6 ++---
 5 files changed, 36 insertions(+), 58 deletions(-)

diff --git a/crypto/af_alg.c b/crypto/af_alg.c
index 7caff10df643..8a35f1364ac3 100644
--- a/crypto/af_alg.c
+++ b/crypto/af_alg.c
@@ -531,45 +531,11 @@ static const struct net_proto_family alg_family = {
 	.owner	=	THIS_MODULE,
 };
 
-int af_alg_make_sg(struct af_alg_sgl *sgl, struct iov_iter *iter, int len)
-{
-	struct page **pages = sgl->pages;
-	size_t off;
-	ssize_t n;
-	int npages, i;
-
-	n = iov_iter_extract_pages(iter, &pages, len, ALG_MAX_PAGES, 0, &off);
-	if (n < 0)
-		return n;
-
-	sgl->need_unpin = iov_iter_extract_will_pin(iter);
-
-	npages = DIV_ROUND_UP(off + n, PAGE_SIZE);
-	if (WARN_ON(npages == 0))
-		return -EINVAL;
-	/* Add one extra for linking */
-	sg_init_table(sgl->sg, npages + 1);
-
-	for (i = 0, len = n; i < npages; i++) {
-		int plen = min_t(int, len, PAGE_SIZE - off);
-
-		sg_set_page(sgl->sg + i, sgl->pages[i], plen, off);
-
-		off = 0;
-		len -= plen;
-	}
-	sg_mark_end(sgl->sg + npages - 1);
-	sgl->npages = npages;
-
-	return n;
-}
-EXPORT_SYMBOL_GPL(af_alg_make_sg);
-
 static void af_alg_link_sg(struct af_alg_sgl *sgl_prev,
 			   struct af_alg_sgl *sgl_new)
 {
-	sg_unmark_end(sgl_prev->sg + sgl_prev->npages - 1);
-	sg_chain(sgl_prev->sg, sgl_prev->npages + 1, sgl_new->sg);
+	sg_unmark_end(sgl_prev->sgt.sgl + sgl_prev->sgt.nents - 1);
+	sg_chain(sgl_prev->sgt.sgl, sgl_prev->sgt.nents + 1, sgl_new->sgt.sgl);
 }
 
 void af_alg_free_sg(struct af_alg_sgl *sgl)
@@ -577,8 +543,8 @@ void af_alg_free_sg(struct af_alg_sgl *sgl)
 	int i;
 
 	if (sgl->need_unpin)
-		for (i = 0; i < sgl->npages; i++)
-			unpin_user_page(sgl->pages[i]);
+		for (i = 0; i < sgl->sgt.nents; i++)
+			unpin_user_page(sg_page(&sgl->sgt.sgl[i]));
 }
 EXPORT_SYMBOL_GPL(af_alg_free_sg);
 
@@ -1292,8 +1258,8 @@ int af_alg_get_rsgl(struct sock *sk, struct msghdr *msg, int flags,
 
 	while (maxsize > len && msg_data_left(msg)) {
 		struct af_alg_rsgl *rsgl;
+		ssize_t err;
 		size_t seglen;
-		int err;
 
 		/* limit the amount of readable buffers */
 		if (!af_alg_readable(sk))
@@ -1310,16 +1276,22 @@ int af_alg_get_rsgl(struct sock *sk, struct msghdr *msg, int flags,
 				return -ENOMEM;
 		}
 
-		rsgl->sgl.npages = 0;
+		rsgl->sgl.sgt.sgl = rsgl->sgl.sgl;
+		rsgl->sgl.sgt.nents = 0;
+		rsgl->sgl.sgt.orig_nents = 0;
 		list_add_tail(&rsgl->list, &areq->rsgl_list);
 
-		/* make one iovec available as scatterlist */
-		err = af_alg_make_sg(&rsgl->sgl, &msg->msg_iter, seglen);
+		sg_init_table(rsgl->sgl.sgt.sgl, ALG_MAX_PAGES);
+		err = extract_iter_to_sg(&msg->msg_iter, seglen, &rsgl->sgl.sgt,
+					 ALG_MAX_PAGES, 0);
 		if (err < 0) {
 			rsgl->sg_num_bytes = 0;
 			return err;
 		}
 
+		sg_mark_end(rsgl->sgl.sgt.sgl + rsgl->sgl.sgt.nents - 1);
+		rsgl->sgl.need_unpin = iov_iter_extract_will_pin(&msg->msg_iter);
+
 		/* chain the new scatterlist with previous one */
 		if (areq->last_rsgl)
 			af_alg_link_sg(&areq->last_rsgl->sgl, &rsgl->sgl);
diff --git a/crypto/algif_aead.c b/crypto/algif_aead.c
index 42493b4d8ce4..f6aa3856d8d5 100644
--- a/crypto/algif_aead.c
+++ b/crypto/algif_aead.c
@@ -210,7 +210,7 @@ static int _aead_recvmsg(struct socket *sock, struct msghdr *msg,
 	 */
 
 	/* Use the RX SGL as source (and destination) for crypto op. */
-	rsgl_src = areq->first_rsgl.sgl.sg;
+	rsgl_src = areq->first_rsgl.sgl.sgt.sgl;
 
 	if (ctx->enc) {
 		/*
@@ -224,7 +224,7 @@ static int _aead_recvmsg(struct socket *sock, struct msghdr *msg,
 		 * RX SGL: AAD || PT || Tag
 		 */
 		err = crypto_aead_copy_sgl(null_tfm, tsgl_src,
-					   areq->first_rsgl.sgl.sg, processed);
+					   areq->first_rsgl.sgl.sgt.sgl, processed);
 		if (err)
 			goto free;
 		af_alg_pull_tsgl(sk, processed, NULL, 0);
@@ -242,7 +242,7 @@ static int _aead_recvmsg(struct socket *sock, struct msghdr *msg,
 
 		 /* Copy AAD || CT to RX SGL buffer for in-place operation. */
 		err = crypto_aead_copy_sgl(null_tfm, tsgl_src,
-					   areq->first_rsgl.sgl.sg, outlen);
+					   areq->first_rsgl.sgl.sgt.sgl, outlen);
 		if (err)
 			goto free;
 
@@ -268,8 +268,8 @@ static int _aead_recvmsg(struct socket *sock, struct msghdr *msg,
 			/* RX SGL present */
 			struct af_alg_sgl *sgl_prev = &areq->last_rsgl->sgl;
 
-			sg_unmark_end(sgl_prev->sg + sgl_prev->npages - 1);
-			sg_chain(sgl_prev->sg, sgl_prev->npages + 1,
+			sg_unmark_end(sgl_prev->sgt.sgl + sgl_prev->sgt.nents - 1);
+			sg_chain(sgl_prev->sgt.sgl, sgl_prev->sgt.nents + 1,
 				 areq->tsgl);
 		} else
 			/* no RX SGL present (e.g. authentication only) */
@@ -278,7 +278,7 @@ static int _aead_recvmsg(struct socket *sock, struct msghdr *msg,
 
 	/* Initialize the crypto operation */
 	aead_request_set_crypt(&areq->cra_u.aead_req, rsgl_src,
-			       areq->first_rsgl.sgl.sg, used, ctx->iv);
+			       areq->first_rsgl.sgl.sgt.sgl, used, ctx->iv);
 	aead_request_set_ad(&areq->cra_u.aead_req, ctx->aead_assoclen);
 	aead_request_set_tfm(&areq->cra_u.aead_req, tfm);
 
diff --git a/crypto/algif_hash.c b/crypto/algif_hash.c
index 63af72e19fa8..16c69c4b9c62 100644
--- a/crypto/algif_hash.c
+++ b/crypto/algif_hash.c
@@ -91,13 +91,21 @@ static int hash_sendmsg(struct socket *sock, struct msghdr *msg,
 		if (len > limit)
 			len = limit;
 
-		len = af_alg_make_sg(&ctx->sgl, &msg->msg_iter, len);
+		ctx->sgl.sgt.sgl = ctx->sgl.sgl;
+		ctx->sgl.sgt.nents = 0;
+		ctx->sgl.sgt.orig_nents = 0;
+
+		len = extract_iter_to_sg(&msg->msg_iter, len, &ctx->sgl.sgt,
+					 ALG_MAX_PAGES, 0);
 		if (len < 0) {
 			err = copied ? 0 : len;
 			goto unlock;
 		}
+		sg_mark_end(ctx->sgl.sgt.sgl + ctx->sgl.sgt.nents);
+
+		ctx->sgl.need_unpin = iov_iter_extract_will_pin(&msg->msg_iter);
 
-		ahash_request_set_crypt(&ctx->req, ctx->sgl.sg, NULL, len);
+		ahash_request_set_crypt(&ctx->req, ctx->sgl.sgt.sgl, NULL, len);
 
 		err = crypto_wait_req(crypto_ahash_update(&ctx->req),
 				      &ctx->wait);
@@ -141,8 +149,8 @@ static ssize_t hash_sendpage(struct socket *sock, struct page *page,
 		flags |= MSG_MORE;
 
 	lock_sock(sk);
-	sg_init_table(ctx->sgl.sg, 1);
-	sg_set_page(ctx->sgl.sg, page, size, offset);
+	sg_init_table(ctx->sgl.sgl, 1);
+	sg_set_page(ctx->sgl.sgl, page, size, offset);
 
 	if (!(flags & MSG_MORE)) {
 		err = hash_alloc_result(sk, ctx);
@@ -151,7 +159,7 @@ static ssize_t hash_sendpage(struct socket *sock, struct page *page,
 	} else if (!ctx->more)
 		hash_free_result(sk, ctx);
 
-	ahash_request_set_crypt(&ctx->req, ctx->sgl.sg, ctx->result, size);
+	ahash_request_set_crypt(&ctx->req, ctx->sgl.sgl, ctx->result, size);
 
 	if (!(flags & MSG_MORE)) {
 		if (ctx->more)
diff --git a/crypto/algif_skcipher.c b/crypto/algif_skcipher.c
index ee8890ee8f33..a251cd6bd5b9 100644
--- a/crypto/algif_skcipher.c
+++ b/crypto/algif_skcipher.c
@@ -105,7 +105,7 @@ static int _skcipher_recvmsg(struct socket *sock, struct msghdr *msg,
 	/* Initialize the crypto operation */
 	skcipher_request_set_tfm(&areq->cra_u.skcipher_req, tfm);
 	skcipher_request_set_crypt(&areq->cra_u.skcipher_req, areq->tsgl,
-				   areq->first_rsgl.sgl.sg, len, ctx->iv);
+				   areq->first_rsgl.sgl.sgt.sgl, len, ctx->iv);
 
 	if (msg->msg_iocb && !is_sync_kiocb(msg->msg_iocb)) {
 		/* AIO operation */
diff --git a/include/crypto/if_alg.h b/include/crypto/if_alg.h
index 46494b33f5bc..34224e77f5a2 100644
--- a/include/crypto/if_alg.h
+++ b/include/crypto/if_alg.h
@@ -56,9 +56,8 @@ struct af_alg_type {
 };
 
 struct af_alg_sgl {
-	struct scatterlist sg[ALG_MAX_PAGES + 1];
-	struct page *pages[ALG_MAX_PAGES];
-	unsigned int npages;
+	struct sg_table sgt;
+	struct scatterlist sgl[ALG_MAX_PAGES + 1];
 	bool need_unpin;
 };
 
@@ -164,7 +163,6 @@ int af_alg_release(struct socket *sock);
 void af_alg_release_parent(struct sock *sk);
 int af_alg_accept(struct sock *sk, struct socket *newsock, bool kern);
 
-int af_alg_make_sg(struct af_alg_sgl *sgl, struct iov_iter *iter, int len);
 void af_alg_free_sg(struct af_alg_sgl *sgl);
 
 static inline struct alg_sock *alg_sk(struct sock *sk)

[PATCH net-next 5/8] crypto: af_alg: Indent the loop in af_alg_sendmsg()

[David Howells]

Put the loop in af_alg_sendmsg() into an if-statement to indent it to make
the next patch easier to review as that will add another branch to handle
MSG_SPLICE_PAGES to the if-statement.

Signed-off-by: David Howells <dhowells@redhat.com>
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: Jens Axboe <axboe@kernel.dk>
cc: Matthew Wilcox <willy@infradead.org>
cc: linux-crypto@vger.kernel.org
cc: netdev@vger.kernel.org
---
 crypto/af_alg.c | 50 +++++++++++++++++++++++++------------------------
 1 file changed, 26 insertions(+), 24 deletions(-)

diff --git a/crypto/af_alg.c b/crypto/af_alg.c
index 8a35f1364ac3..17ecaae50af7 100644
--- a/crypto/af_alg.c
+++ b/crypto/af_alg.c
@@ -1030,35 +1030,37 @@ int af_alg_sendmsg(struct socket *sock, struct msghdr *msg, size_t size,
 		if (sgl->cur)
 			sg_unmark_end(sg + sgl->cur - 1);
 
-		do {
-			struct page *pg;
-			unsigned int i = sgl->cur;
+		if (1 /* TODO check MSG_SPLICE_PAGES */) {
+			do {
+				struct page *pg;
+				unsigned int i = sgl->cur;
 
-			plen = min_t(size_t, len, PAGE_SIZE);
+				plen = min_t(size_t, len, PAGE_SIZE);
 
-			pg = alloc_page(GFP_KERNEL);
-			if (!pg) {
-				err = -ENOMEM;
-				goto unlock;
-			}
+				pg = alloc_page(GFP_KERNEL);
+				if (!pg) {
+					err = -ENOMEM;
+					goto unlock;
+				}
 
-			sg_assign_page(sg + i, pg);
+				sg_assign_page(sg + i, pg);
 
-			err = memcpy_from_msg(page_address(sg_page(sg + i)),
-					      msg, plen);
-			if (err) {
-				__free_page(sg_page(sg + i));
-				sg_assign_page(sg + i, NULL);
-				goto unlock;
-			}
+				err = memcpy_from_msg(page_address(sg_page(sg + i)),
+						      msg, plen);
+				if (err) {
+					__free_page(sg_page(sg + i));
+					sg_assign_page(sg + i, NULL);
+					goto unlock;
+				}
 
-			sg[i].length = plen;
-			len -= plen;
-			ctx->used += plen;
-			copied += plen;
-			size -= plen;
-			sgl->cur++;
-		} while (len && sgl->cur < MAX_SGL_ENTS);
+				sg[i].length = plen;
+				len -= plen;
+				ctx->used += plen;
+				copied += plen;
+				size -= plen;
+				sgl->cur++;
+			} while (len && sgl->cur < MAX_SGL_ENTS);
+		}
 
 		if (!size)
 			sg_mark_end(sg + sgl->cur - 1);

[PATCH net-next 6/8] crypto: af_alg: Support MSG_SPLICE_PAGES

[David Howells]

Make AF_ALG sendmsg() support MSG_SPLICE_PAGES.  This causes pages to be
spliced from the source iterator.

This allows ->sendpage() to be replaced by something that can handle
multiple multipage folios in a single transaction.

Signed-off-by: David Howells <dhowells@redhat.com>
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: Jens Axboe <axboe@kernel.dk>
cc: Matthew Wilcox <willy@infradead.org>
cc: linux-crypto@vger.kernel.org
cc: netdev@vger.kernel.org
---
 crypto/af_alg.c         | 28 ++++++++++++++++++++++++++--
 crypto/algif_aead.c     | 22 +++++++++++-----------
 crypto/algif_skcipher.c |  8 ++++----
 3 files changed, 41 insertions(+), 17 deletions(-)

diff --git a/crypto/af_alg.c b/crypto/af_alg.c
index 17ecaae50af7..979033600185 100644
--- a/crypto/af_alg.c
+++ b/crypto/af_alg.c
@@ -940,6 +940,10 @@ int af_alg_sendmsg(struct socket *sock, struct msghdr *msg, size_t size,
 	bool init = false;
 	int err = 0;
 
+	if ((msg->msg_flags & MSG_SPLICE_PAGES) &&
+	    !iov_iter_is_bvec(&msg->msg_iter))
+		return -EINVAL;
+
 	if (msg->msg_controllen) {
 		err = af_alg_cmsg_send(msg, &con);
 		if (err)
@@ -985,7 +989,7 @@ int af_alg_sendmsg(struct socket *sock, struct msghdr *msg, size_t size,
 	while (size) {
 		struct scatterlist *sg;
 		size_t len = size;
-		size_t plen;
+		ssize_t plen;
 
 		/* use the existing memory in an allocated page */
 		if (ctx->merge) {
@@ -1030,7 +1034,27 @@ int af_alg_sendmsg(struct socket *sock, struct msghdr *msg, size_t size,
 		if (sgl->cur)
 			sg_unmark_end(sg + sgl->cur - 1);
 
-		if (1 /* TODO check MSG_SPLICE_PAGES */) {
+		if (msg->msg_flags & MSG_SPLICE_PAGES) {
+			struct sg_table sgtable = {
+				.sgl		= sg,
+				.nents		= sgl->cur,
+				.orig_nents	= sgl->cur,
+			};
+
+			plen = extract_iter_to_sg(&msg->msg_iter, len, &sgtable,
+						  MAX_SGL_ENTS, 0);
+			if (plen < 0) {
+				err = plen;
+				goto unlock;
+			}
+
+			for (; sgl->cur < sgtable.nents; sgl->cur++)
+				get_page(sg_page(&sg[sgl->cur]));
+			len -= plen;
+			ctx->used += plen;
+			copied += plen;
+			size -= plen;
+		} else {
 			do {
 				struct page *pg;
 				unsigned int i = sgl->cur;
diff --git a/crypto/algif_aead.c b/crypto/algif_aead.c
index f6aa3856d8d5..b16111a3025a 100644
--- a/crypto/algif_aead.c
+++ b/crypto/algif_aead.c
@@ -9,8 +9,8 @@
  * The following concept of the memory management is used:
  *
  * The kernel maintains two SGLs, the TX SGL and the RX SGL. The TX SGL is
- * filled by user space with the data submitted via sendpage/sendmsg. Filling
- * up the TX SGL does not cause a crypto operation -- the data will only be
+ * filled by user space with the data submitted via sendpage. Filling up
+ * the TX SGL does not cause a crypto operation -- the data will only be
  * tracked by the kernel. Upon receipt of one recvmsg call, the caller must
  * provide a buffer which is tracked with the RX SGL.
  *
@@ -113,19 +113,19 @@ static int _aead_recvmsg(struct socket *sock, struct msghdr *msg,
 	}
 
 	/*
-	 * Data length provided by caller via sendmsg/sendpage that has not
-	 * yet been processed.
+	 * Data length provided by caller via sendmsg that has not yet been
+	 * processed.
 	 */
 	used = ctx->used;
 
 	/*
-	 * Make sure sufficient data is present -- note, the same check is
-	 * also present in sendmsg/sendpage. The checks in sendpage/sendmsg
-	 * shall provide an information to the data sender that something is
-	 * wrong, but they are irrelevant to maintain the kernel integrity.
-	 * We need this check here too in case user space decides to not honor
-	 * the error message in sendmsg/sendpage and still call recvmsg. This
-	 * check here protects the kernel integrity.
+	 * Make sure sufficient data is present -- note, the same check is also
+	 * present in sendmsg. The checks in sendmsg shall provide an
+	 * information to the data sender that something is wrong, but they are
+	 * irrelevant to maintain the kernel integrity.  We need this check
+	 * here too in case user space decides to not honor the error message
+	 * in sendmsg and still call recvmsg. This check here protects the
+	 * kernel integrity.
 	 */
 	if (!aead_sufficient_data(sk))
 		return -EINVAL;
diff --git a/crypto/algif_skcipher.c b/crypto/algif_skcipher.c
index a251cd6bd5b9..b1f321b9f846 100644
--- a/crypto/algif_skcipher.c
+++ b/crypto/algif_skcipher.c
@@ -9,10 +9,10 @@
  * The following concept of the memory management is used:
  *
  * The kernel maintains two SGLs, the TX SGL and the RX SGL. The TX SGL is
- * filled by user space with the data submitted via sendpage/sendmsg. Filling
- * up the TX SGL does not cause a crypto operation -- the data will only be
- * tracked by the kernel. Upon receipt of one recvmsg call, the caller must
- * provide a buffer which is tracked with the RX SGL.
+ * filled by user space with the data submitted via sendmsg. Filling up the TX
+ * SGL does not cause a crypto operation -- the data will only be tracked by
+ * the kernel. Upon receipt of one recvmsg call, the caller must provide a
+ * buffer which is tracked with the RX SGL.
  *
  * During the processing of the recvmsg operation, the cipher request is
  * allocated and prepared. As part of the recvmsg operation, the processed

[PATCH net-next 7/8] crypto: af_alg: Convert af_alg_sendpage() to use MSG_SPLICE_PAGES

[David Howells]

Convert af_alg_sendpage() to use sendmsg() with MSG_SPLICE_PAGES rather
than directly splicing in the pages itself.

This allows ->sendpage() to be replaced by something that can handle
multiple multipage folios in a single transaction.

Signed-off-by: David Howells <dhowells@redhat.com>
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: Jens Axboe <axboe@kernel.dk>
cc: Matthew Wilcox <willy@infradead.org>
cc: linux-crypto@vger.kernel.org
cc: netdev@vger.kernel.org
---
 crypto/af_alg.c | 52 ++++++++-----------------------------------------
 1 file changed, 8 insertions(+), 44 deletions(-)

diff --git a/crypto/af_alg.c b/crypto/af_alg.c
index 979033600185..105afd77a064 100644
--- a/crypto/af_alg.c
+++ b/crypto/af_alg.c
@@ -1117,53 +1117,17 @@ EXPORT_SYMBOL_GPL(af_alg_sendmsg);
 ssize_t af_alg_sendpage(struct socket *sock, struct page *page,
 			int offset, size_t size, int flags)
 {
-	struct sock *sk = sock->sk;
-	struct alg_sock *ask = alg_sk(sk);
-	struct af_alg_ctx *ctx = ask->private;
-	struct af_alg_tsgl *sgl;
-	int err = -EINVAL;
+	struct bio_vec bvec;
+	struct msghdr msg = {
+		.msg_flags = flags | MSG_SPLICE_PAGES,
+	};
 
 	if (flags & MSG_SENDPAGE_NOTLAST)
-		flags |= MSG_MORE;
-
-	lock_sock(sk);
-	if (!ctx->more && ctx->used)
-		goto unlock;
-
-	if (!size)
-		goto done;
-
-	if (!af_alg_writable(sk)) {
-		err = af_alg_wait_for_wmem(sk, flags);
-		if (err)
-			goto unlock;
-	}
-
-	err = af_alg_alloc_tsgl(sk);
-	if (err)
-		goto unlock;
-
-	ctx->merge = 0;
-	sgl = list_entry(ctx->tsgl_list.prev, struct af_alg_tsgl, list);
-
-	if (sgl->cur)
-		sg_unmark_end(sgl->sg + sgl->cur - 1);
-
-	sg_mark_end(sgl->sg + sgl->cur);
-
-	get_page(page);
-	sg_set_page(sgl->sg + sgl->cur, page, size, offset);
-	sgl->cur++;
-	ctx->used += size;
-
-done:
-	ctx->more = flags & MSG_MORE;
-
-unlock:
-	af_alg_data_wakeup(sk);
-	release_sock(sk);
+		msg.msg_flags |= MSG_MORE;
 
-	return err ?: size;
+	bvec_set_page(&bvec, page, size, offset);
+	iov_iter_bvec(&msg.msg_iter, ITER_SOURCE, &bvec, 1, size);
+	return sock_sendmsg(sock, &msg);
 }
 EXPORT_SYMBOL_GPL(af_alg_sendpage);
 

[PATCH net-next 8/8] crypto: af_alg/hash: Support MSG_SPLICE_PAGES

[David Howells]

Make AF_ALG sendmsg() support MSG_SPLICE_PAGES in the hashing code.  This
causes pages to be spliced from the source iterator if possible.

This allows ->sendpage() to be replaced by something that can handle
multiple multipage folios in a single transaction.

Signed-off-by: David Howells <dhowells@redhat.com>
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: Jens Axboe <axboe@kernel.dk>
cc: Matthew Wilcox <willy@infradead.org>
cc: linux-crypto@vger.kernel.org
cc: netdev@vger.kernel.org
---
 crypto/af_alg.c     |  11 +++--
 crypto/algif_hash.c | 100 +++++++++++++++++++++++++++-----------------
 2 files changed, 70 insertions(+), 41 deletions(-)

diff --git a/crypto/af_alg.c b/crypto/af_alg.c
index 105afd77a064..1965fc4641ed 100644
--- a/crypto/af_alg.c
+++ b/crypto/af_alg.c
@@ -542,9 +542,14 @@ void af_alg_free_sg(struct af_alg_sgl *sgl)
 {
 	int i;
 
-	if (sgl->need_unpin)
-		for (i = 0; i < sgl->sgt.nents; i++)
-			unpin_user_page(sg_page(&sgl->sgt.sgl[i]));
+	if (sgl->sgt.sgl) {
+		if (sgl->need_unpin)
+			for (i = 0; i < sgl->sgt.nents; i++)
+				unpin_user_page(sg_page(&sgl->sgt.sgl[i]));
+		if (sgl->sgt.sgl != sgl->sgl)
+			kvfree(sgl->sgt.sgl);
+		sgl->sgt.sgl = NULL;
+	}
 }
 EXPORT_SYMBOL_GPL(af_alg_free_sg);
 
diff --git a/crypto/algif_hash.c b/crypto/algif_hash.c
index 16c69c4b9c62..3d96c0e06ca6 100644
--- a/crypto/algif_hash.c
+++ b/crypto/algif_hash.c
@@ -63,78 +63,102 @@ static void hash_free_result(struct sock *sk, struct hash_ctx *ctx)
 static int hash_sendmsg(struct socket *sock, struct msghdr *msg,
 			size_t ignored)
 {
-	int limit = ALG_MAX_PAGES * PAGE_SIZE;
 	struct sock *sk = sock->sk;
 	struct alg_sock *ask = alg_sk(sk);
 	struct hash_ctx *ctx = ask->private;
-	long copied = 0;
+	ssize_t copied = 0;
+	size_t len, max_pages = ALG_MAX_PAGES, npages;
+	bool continuing = ctx->more, need_init = false;
 	int err;
 
-	if (limit > sk->sk_sndbuf)
-		limit = sk->sk_sndbuf;
+	/* Don't limit to ALG_MAX_PAGES if the pages are all already pinned. */
+	if (!user_backed_iter(&msg->msg_iter))
+		max_pages = INT_MAX;
+	else
+		max_pages = min_t(size_t, max_pages,
+				  DIV_ROUND_UP(sk->sk_sndbuf, PAGE_SIZE));
 
 	lock_sock(sk);
-	if (!ctx->more) {
+	if (!continuing) {
 		if ((msg->msg_flags & MSG_MORE))
 			hash_free_result(sk, ctx);
-
-		err = crypto_wait_req(crypto_ahash_init(&ctx->req), &ctx->wait);
-		if (err)
-			goto unlock;
+		need_init = true;
 	}
 
 	ctx->more = false;
 
 	while (msg_data_left(msg)) {
-		int len = msg_data_left(msg);
-
-		if (len > limit)
-			len = limit;
-
 		ctx->sgl.sgt.sgl = ctx->sgl.sgl;
 		ctx->sgl.sgt.nents = 0;
 		ctx->sgl.sgt.orig_nents = 0;
 
-		len = extract_iter_to_sg(&msg->msg_iter, len, &ctx->sgl.sgt,
-					 ALG_MAX_PAGES, 0);
-		if (len < 0) {
-			err = copied ? 0 : len;
-			goto unlock;
+		err = -EIO;
+		npages = iov_iter_npages(&msg->msg_iter, max_pages);
+		if (npages == 0)
+			goto unlock_free;
+
+		if (npages > ARRAY_SIZE(ctx->sgl.sgl)) {
+			err = -ENOMEM;
+			ctx->sgl.sgt.sgl =
+				kvmalloc(array_size(npages, sizeof(*ctx->sgl.sgt.sgl)),
+					GFP_KERNEL);
+			if (!ctx->sgl.sgt.sgl)
+				goto unlock_free;
 		}
-		sg_mark_end(ctx->sgl.sgt.sgl + ctx->sgl.sgt.nents);
+		sg_init_table(ctx->sgl.sgl, npages);
 
 		ctx->sgl.need_unpin = iov_iter_extract_will_pin(&msg->msg_iter);
 
-		ahash_request_set_crypt(&ctx->req, ctx->sgl.sgt.sgl, NULL, len);
+		err = extract_iter_to_sg(&msg->msg_iter, LONG_MAX,
+					 &ctx->sgl.sgt, npages, 0);
+		if (err < 0)
+			goto unlock_free;
+		len = err;
+		sg_mark_end(ctx->sgl.sgt.sgl + ctx->sgl.sgt.nents - 1);
 
-		err = crypto_wait_req(crypto_ahash_update(&ctx->req),
-				      &ctx->wait);
-		af_alg_free_sg(&ctx->sgl);
-		if (err) {
-			iov_iter_revert(&msg->msg_iter, len);
-			goto unlock;
+		if (!msg_data_left(msg)) {
+			err = hash_alloc_result(sk, ctx);
+			if (err)
+				goto unlock_free;
 		}
 
-		copied += len;
-	}
+		ahash_request_set_crypt(&ctx->req, ctx->sgl.sgt.sgl, ctx->result, len);
 
-	err = 0;
+		if (!msg_data_left(msg) && !continuing && !(msg->msg_flags & MSG_MORE)) {
+			err = crypto_ahash_digest(&ctx->req);
+		} else {
+			if (need_init) {
+				err = crypto_wait_req(crypto_ahash_init(&ctx->req),
+						      &ctx->wait);
+				if (err)
+					goto unlock_free;
+				need_init = false;
+			}
+
+			if (msg_data_left(msg) || (msg->msg_flags & MSG_MORE))
+				err = crypto_ahash_update(&ctx->req);
+			else
+				err = crypto_ahash_finup(&ctx->req);
+			continuing = true;
+		}
 
-	ctx->more = msg->msg_flags & MSG_MORE;
-	if (!ctx->more) {
-		err = hash_alloc_result(sk, ctx);
+		err = crypto_wait_req(err, &ctx->wait);
 		if (err)
-			goto unlock;
+			goto unlock_free;
 
-		ahash_request_set_crypt(&ctx->req, NULL, ctx->result, 0);
-		err = crypto_wait_req(crypto_ahash_final(&ctx->req),
-				      &ctx->wait);
+		copied += len;
+		af_alg_free_sg(&ctx->sgl);
 	}
 
+	ctx->more = msg->msg_flags & MSG_MORE;
+	err = 0;
 unlock:
 	release_sock(sk);
+	return copied ?: err;
 
-	return err ?: copied;
+unlock_free:
+	af_alg_free_sg(&ctx->sgl);
+	goto unlock;
 }
 
 static ssize_t hash_sendpage(struct socket *sock, struct page *page,

Re: [PATCH net-next 1/8] Move netfs_extract_iter_to_sg() to lib/scatterlist.c

[Simon Horman]

On Fri, May 26, 2023 at 03:30:57PM +0100, David Howells wrote:

...

> +/**
> + * netfs_extract_iter_to_sg - Extract pages from an iterator and add ot 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 successul, @sgtable->nents is updated to include the number of elements

Hi David,

I know you are just moving things about here.
But if you need to re-spin for some other reason,
perhaps you could correct the spelling of successful.

> + * 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.
> + */

...

Re: [PATCH net-next 2/8] Drop the netfs_ prefix from netfs_extract_iter_to_sg()

[Simon Horman]

On Fri, May 26, 2023 at 03:30:58PM +0100, David Howells wrote:

...

> @@ -1307,7 +1307,7 @@ static ssize_t netfs_extract_xarray_to_sg(struct iov_iter *iter,
>  }
>  
>  /**
> - * netfs_extract_iter_to_sg - Extract pages from an iterator and add ot an sglist
> + * extract_iter_to_sg - Extract pages from an iterator and add ot an sglist

nit: While we are here, perhaps

     s/and add ot an/and add to an/

>   * @iter: The iterator to extract from
>   * @maxsize: The amount of iterator to copy
>   * @sgtable: The scatterlist table to fill in

..

Re: [PATCH net-next 1/8] Move netfs_extract_iter_to_sg() to lib/scatterlist.c

[David Howells]

If it comes to a respin, I'll stick in an extra patch to fix the spellings -
and if not, I'll submit the patch separately.  It shouldn't be changed in with
the movement of code to give git analysis a better chance of tracking the
movement.

David