tls/device: Support MSG_SPLICE_PAGES

Make TLS's device sendmsg() support MSG_SPLICE_PAGES.  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>
Reviewed-by: Jakub Kicinski <kuba@kernel.org>
cc: Chuck Lever <chuck.lever@oracle.com>
cc: Boris Pismenny <borisp@nvidia.com>
cc: John Fastabend <john.fastabend@gmail.com>
cc: Jens Axboe <axboe@kernel.dk>
cc: Matthew Wilcox <willy@infradead.org>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

diff --git a/net/tls/tls_device.c b/net/tls/tls_device.c
index 439be83..bb3bb52 100644 (file)
--- a/net/tls/tls_device.c
+++ b/net/tls/tls_device.c
@@ -509,6 +509,29 @@ handle_error:
                        tls_append_frag(record, &zc_pfrag, copy);
 
                        iter_offset.offset += copy;
+               } else 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);
+                       if (rc <= 0) {
+                               if (rc == 0)
+                                       rc = -EIO;
+                               goto handle_error;
+                       }
+                       copy = rc;
+
+                       if (WARN_ON_ONCE(!sendpage_ok(zc_pfrag.page))) {
+                               iov_iter_revert(iter_offset.msg_iter, copy);
+                               rc = -EIO;
+                               goto handle_error;
+                       }
+
+                       zc_pfrag.offset = off;
+                       zc_pfrag.size = copy;
+                       tls_append_frag(record, &zc_pfrag, copy);
                } else if (copy) {
                        copy = min_t(size_t, copy, pfrag->size - pfrag->offset);
 
@@ -572,6 +595,9 @@ int tls_device_sendmsg(struct sock *sk, struct msghdr *msg, size_t size)
        union tls_iter_offset iter;
        int rc;
 
+       if (!tls_ctx->zerocopy_sendfile)
+               msg->msg_flags &= ~MSG_SPLICE_PAGES;
+
        mutex_lock(&tls_ctx->tx_lock);
        lock_sock(sk);