@@ -1417,10 +1417,10 @@ int tcp_sendmsg_locked(struct sock *sk, struct msghdr *msg, size_t size)
goto do_error;
copy = err;
} else if (zc == 2) {
- /* Splice in data. */
+ /* Splice in data if we can; copy if we can't. */
struct page *page = NULL, **pages = &page;
size_t off = 0, part;
- bool can_coalesce;
+ bool can_coalesce, put = false;
int i = skb_shinfo(skb)->nr_frags;
copy = iov_iter_extract_pages(&msg->msg_iter, &pages,
@@ -1447,12 +1447,34 @@ int tcp_sendmsg_locked(struct sock *sk, struct msghdr *msg, size_t size)
goto wait_for_space;
copy = part;
+ if (!sendpage_ok(page)) {
+ const void *p = kmap_local_page(page);
+ void *q;
+
+ q = page_frag_memdup(NULL, p + off, copy,
+ sk->sk_allocation, ULONG_MAX);
+ kunmap_local(p);
+ if (!q) {
+ iov_iter_revert(&msg->msg_iter, copy);
+ err = copy ?: -ENOMEM;
+ goto do_error;
+ }
+ page = virt_to_page(q);
+ off = offset_in_page(q);
+ put = true;
+ can_coalesce = false;
+ }
+
if (can_coalesce) {
skb_frag_size_add(&skb_shinfo(skb)->frags[i - 1], copy);
} else {
- get_page(page);
+ if (!put)
+ get_page(page);
+ put = false;
skb_fill_page_desc_noacc(skb, i, page, off, copy);
}
+ if (put)
+ put_page(page);
page = NULL;
if (!(flags & MSG_NO_SHARED_FRAGS))
If sendmsg() with MSG_SPLICE_PAGES encounters a page that shouldn't be spliced - a slab page, for instance, or one with a zero count - make tcp_sendmsg() copy it. Signed-off-by: David Howells <dhowells@redhat.com> cc: Eric Dumazet <edumazet@google.com> cc: "David S. Miller" <davem@davemloft.net> 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: netdev@vger.kernel.org --- net/ipv4/tcp.c | 28 +++++++++++++++++++++++++--- 1 file changed, 25 insertions(+), 3 deletions(-)