[PATCH net-next v5 14/14] tls/device: Convert tls_device_sendpage() to use MSG_SPLICE_PAGES

David Howells
2023-06-07T14:47:11Z

Convert tls_device_sendpage() to use sendmsg() with MSG_SPLICE_PAGES rather
than directly splicing in the pages itself. With that, the tls_iter_offset
union is no longer necessary and can be replaced with an iov_iter pointer
and the zc_page argument to tls_push_data() can also be removed.

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: Chuck Lever <chuck.lever@oracle.com>
cc: Boris Pismenny <borisp@nvidia.com>
cc: John Fastabend <john.fastabend@gmail.com>
cc: Jakub Kicinski <kuba@kernel.org>
cc: Eric Dumazet <edumazet@google.com>
cc: "David S. Miller" <davem@davemloft.net>
cc: Paolo Abeni <pabeni@redhat.com>
cc: Jens Axboe <axboe@kernel.dk>
cc: Matthew Wilcox <willy@infradead.org>
cc: netdev@vger.kernel.org
---
net/tls/tls_device.c | 92 +++++++++++---------------------------------
1 file changed, 23 insertions(+), 69 deletions(-)

diff --git a/net/tls/tls_device.c b/net/tls/tls_device.c
index bb3bb523544e..b4864d55900f 100644
--- a/net/tls/tls_device.c
+++ b/net/tls/tls_device.c
@@ -422,16 +422,10 @@ static int tls_device_copy_data(void *addr, size_t bytes, struct iov_iter *i)
return 0;
}

-union tls_iter_offset {
- struct iov_iter *msg_iter;
- int offset;
-};
-
static int tls_push_data(struct sock *sk,
- union tls_iter_offset iter_offset,
+ struct iov_iter *iter,
size_t size, int flags,
- unsigned char record_type,
- struct page *zc_page)
+ unsigned char record_type)
{
struct tls_context *tls_ctx = tls_get_ctx(sk);
struct tls_prot_info *prot = &tls_ctx->prot_info;
@@ -500,22 +494,13 @@ static int tls_push_data(struct sock *sk,
record = ctx->open_record;

copy = min_t(size_t, size, max_open_record_len - record->len);
- if (copy && zc_page) {
- struct page_frag zc_pfrag;
-
- zc_pfrag.page = zc_page;
- zc_pfrag.offset = iter_offset.offset;
- zc_pfrag.size = copy;
- tls_append_frag(record, &zc_pfrag, copy);
-
- iter_offset.offset += copy;
- } else if (copy && (flags & MSG_SPLICE_PAGES)) {
+ if (copy && (flags & MSG_SPLICE_PAGES)) {
struct page_frag zc_pfrag;
struct page **pages = &zc_pfrag.page;
size_t off;

- rc = iov_iter_extract_pages(iter_offset.msg_iter,
- &pages, copy, 1, 0, &off);
+ rc = iov_iter_extract_pages(iter, &pages,
+ copy, 1, 0, &off);
if (rc <= 0) {
if (rc == 0)
rc = -EIO;
@@ -524,7 +509,7 @@ static int tls_push_data(struct sock *sk,
copy = rc;

if (WARN_ON_ONCE(!sendpage_ok(zc_pfrag.page))) {
- iov_iter_revert(iter_offset.msg_iter, copy);
+ iov_iter_revert(iter, copy);
rc = -EIO;
goto handle_error;
}
@@ -537,7 +522,7 @@ static int tls_push_data(struct sock *sk,

rc = tls_device_copy_data(page_address(pfrag->page) +
pfrag->offset, copy,
- iter_offset.msg_iter);
+ iter);
if (rc)
goto handle_error;
tls_append_frag(record, pfrag, copy);
@@ -592,7 +577,6 @@ int tls_device_sendmsg(struct sock *sk, struct msghdr *msg, size_t size)
{
unsigned char record_type = TLS_RECORD_TYPE_DATA;
struct tls_context *tls_ctx = tls_get_ctx(sk);
- union tls_iter_offset iter;
int rc;

if (!tls_ctx->zerocopy_sendfile)
@@ -607,8 +591,8 @@ int tls_device_sendmsg(struct sock *sk, struct msghdr *msg, size_t size)
goto out;
}

- iter.msg_iter = &msg->msg_iter;
- rc = tls_push_data(sk, iter, size, msg->msg_flags, record_type, NULL);
+ rc = tls_push_data(sk, &msg->msg_iter, size, msg->msg_flags,
+ record_type);

out:
release_sock(sk);
@@ -620,8 +604,7 @@ void tls_device_splice_eof(struct socket *sock)
{
struct sock *sk = sock->sk;
struct tls_context *tls_ctx = tls_get_ctx(sk);
- union tls_iter_offset iter;
- struct iov_iter iov_iter = {};
+ struct iov_iter iter = {};

if (!tls_is_partially_sent_record(tls_ctx))
return;
@@ -630,9 +613,8 @@ void tls_device_splice_eof(struct socket *sock)
lock_sock(sk);

if (tls_is_partially_sent_record(tls_ctx)) {
- iov_iter_bvec(&iov_iter, ITER_SOURCE, NULL, 0, 0);
- iter.msg_iter = &iov_iter;
- tls_push_data(sk, iter, 0, 0, TLS_RECORD_TYPE_DATA, NULL);
+ iov_iter_bvec(&iter, ITER_SOURCE, NULL, 0, 0);
+ tls_push_data(sk, &iter, 0, 0, TLS_RECORD_TYPE_DATA);
}

release_sock(sk);
@@ -642,44 +624,18 @@ void tls_device_splice_eof(struct socket *sock)
int tls_device_sendpage(struct sock *sk, struct page *page,
int offset, size_t size, int flags)
{
- struct tls_context *tls_ctx = tls_get_ctx(sk);
- union tls_iter_offset iter_offset;
- struct iov_iter msg_iter;
- char *kaddr;
- struct kvec iov;
- int rc;
+ struct bio_vec bvec;
+ struct msghdr msg = { .msg_flags = flags | MSG_SPLICE_PAGES, };

if (flags & MSG_SENDPAGE_NOTLAST)
- flags |= MSG_MORE;
-
- mutex_lock(&tls_ctx->tx_lock);
- lock_sock(sk);
+ msg.msg_flags |= MSG_MORE;

- if (flags & MSG_OOB) {
- rc = -EOPNOTSUPP;
- goto out;
- }
-
- if (tls_ctx->zerocopy_sendfile) {
- iter_offset.offset = offset;
- rc = tls_push_data(sk, iter_offset, size,
- flags, TLS_RECORD_TYPE_DATA, page);
- goto out;
- }
-
- kaddr = kmap(page);
- iov.iov_base = kaddr + offset;
- iov.iov_len = size;
- iov_iter_kvec(&msg_iter, ITER_SOURCE, &iov, 1, size);
- iter_offset.msg_iter = &msg_iter;
- rc = tls_push_data(sk, iter_offset, size, flags, TLS_RECORD_TYPE_DATA,
- NULL);
- kunmap(page);
+ if (flags & MSG_OOB)
+ return -EOPNOTSUPP;

-out:
- release_sock(sk);
- mutex_unlock(&tls_ctx->tx_lock);
- return rc;
+ bvec_set_page(&bvec, page, size, offset);
+ iov_iter_bvec(&msg.msg_iter, ITER_SOURCE, &bvec, 1, size);
+ return tls_device_sendmsg(sk, &msg, size);
}

struct tls_record_info *tls_get_record(struct tls_offload_context_tx *context,
@@ -744,12 +700,10 @@ EXPORT_SYMBOL(tls_get_record);

static int tls_device_push_pending_record(struct sock *sk, int flags)
{
- union tls_iter_offset iter;
- struct iov_iter msg_iter;
+ struct iov_iter iter;

- iov_iter_kvec(&msg_iter, ITER_SOURCE, NULL, 0, 0);
- iter.msg_iter = &msg_iter;
- return tls_push_data(sk, iter, 0, flags, TLS_RECORD_TYPE_DATA, NULL);
+ iov_iter_kvec(&iter, ITER_SOURCE, NULL, 0, 0);
+ return tls_push_data(sk, &iter, 0, flags, TLS_RECORD_TYPE_DATA);
}

void tls_device_write_space(struct sock *sk, struct tls_context *ctx)