[PATCH] tcp: fix tcp_fastopen unaligned access complaints on sparc

From: Shannon Nelson
Date: Thu Jan 12 2017 - 14:59:47 EST


Fix up a data alignment issue on sparc by swapping the order
of the cookie byte array field with the length field in
struct tcp_fastopen_cookie

This addresses log complaints like these:
log_unaligned: 113 callbacks suppressed
Kernel unaligned access at TPC[976490] tcp_try_fastopen+0x2d0/0x360
Kernel unaligned access at TPC[9764ac] tcp_try_fastopen+0x2ec/0x360
Kernel unaligned access at TPC[9764c8] tcp_try_fastopen+0x308/0x360
Kernel unaligned access at TPC[9764e4] tcp_try_fastopen+0x324/0x360
Kernel unaligned access at TPC[976490] tcp_try_fastopen+0x2d0/0x360

Signed-off-by: Shannon Nelson <shannon.nelson@xxxxxxxxxx>
---
include/linux/tcp.h | 2 +-
1 files changed, 1 insertions(+), 1 deletions(-)

diff --git a/include/linux/tcp.h b/include/linux/tcp.h
index fc5848d..95cda75 100644
--- a/include/linux/tcp.h
+++ b/include/linux/tcp.h
@@ -62,8 +62,8 @@ static inline unsigned int tcp_optlen(const struct sk_buff *skb)

/* TCP Fast Open Cookie as stored in memory */
struct tcp_fastopen_cookie {
- s8 len;
u8 val[TCP_FASTOPEN_COOKIE_MAX];
+ s8 len;
bool exp; /* In RFC6994 experimental option format */
};

--
1.7.1