Re: Data corruption issue with splice() on 2.6.27.10

From: Jarek Poplawski
Date: Mon Jan 12 2009 - 08:15:38 EST


On Mon, Jan 12, 2009 at 11:02:57PM +1100, Herbert Xu wrote:
> On Wed, Jan 07, 2009 at 11:52:17PM +1100, Herbert Xu wrote:
> > On Wed, Jan 07, 2009 at 12:49:46PM +0000, Jarek Poplawski wrote:
> > >
> > > Hmm... in any case: take 3
> >
> > Yes this should fix the corruption but it kind of defeats the
> > purpose of splice by copying the data.
>
> However, as we don't have a better fix yet, we probably should
> take Jarek's patch for now since data corruption is bad.
>

I've wondered if something like this could work as a temporary hack?

!!! not compiled/tested !!!
---

diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c
index ce572f9..99b0876 100644
--- a/net/ipv4/tcp.c
+++ b/net/ipv4/tcp.c
@@ -264,6 +264,7 @@
#include <linux/cache.h>
#include <linux/err.h>
#include <linux/crypto.h>
+#include <linux/page-flags.h>

#include <net/icmp.h>
#include <net/tcp.h>
@@ -776,7 +777,8 @@ ssize_t tcp_sendpage(struct socket *sock, struct page *page, int offset,
struct sock *sk = sock->sk;

if (!(sk->sk_route_caps & NETIF_F_SG) ||
- !(sk->sk_route_caps & NETIF_F_ALL_CSUM))
+ !(sk->sk_route_caps & NETIF_F_ALL_CSUM) ||
+ PageSlab(page))
return sock_no_sendpage(sock, page, offset, size, flags);

lock_sock(sk);
--
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