* [PATCH v2] lib/checksum.c: fix carry in csum_tcpudp_nofold
@ 2015-01-28 9:58 Karl Beldan
2015-01-28 13:04 ` Eric Dumazet
2015-01-29 6:32 ` David Miller
0 siblings, 2 replies; 4+ messages in thread
From: Karl Beldan @ 2015-01-28 9:58 UTC (permalink / raw)
Cc: Karl Beldan, Karl Beldan, Al Viro, Eric Dumazet, Arnd Bergmann,
Mike Frysinger, netdev, linux-kernel, stable
The carry from the 64->32bits folding was dropped, e.g with:
saddr=0xFFFFFFFF daddr=0xFF0000FF len=0xFFFF proto=0 sum=1,
csum_tcpudp_nofold returned 0 instead of 1.
Signed-off-by: Karl Beldan <karl.beldan@rivierawaves.com>
Cc: Al Viro <viro@ZenIV.linux.org.uk>
Cc: Eric Dumazet <eric.dumazet@gmail.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Mike Frysinger <vapier@gentoo.org>
Cc: netdev@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Cc: stable@vger.kernel.org
---
lib/checksum.c | 12 ++++++++++--
1 file changed, 10 insertions(+), 2 deletions(-)
diff --git a/lib/checksum.c b/lib/checksum.c
index 129775e..fcf3894 100644
--- a/lib/checksum.c
+++ b/lib/checksum.c
@@ -47,6 +47,15 @@ static inline unsigned short from32to16(unsigned int x)
return x;
}
+static inline u32 from64to32(u64 x)
+{
+ /* add up 32-bit and 32-bit for 32+c bit */
+ x = (x & 0xffffffff) + (x >> 32);
+ /* add up carry.. */
+ x = (x & 0xffffffff) + (x >> 32);
+ return (u32)x;
+}
+
static unsigned int do_csum(const unsigned char *buff, int len)
{
int odd;
@@ -195,8 +204,7 @@ __wsum csum_tcpudp_nofold(__be32 saddr, __be32 daddr,
#else
s += (proto + len) << 8;
#endif
- s += (s >> 32);
- return (__force __wsum)s;
+ return (__force __wsum)from64to32(s);
}
EXPORT_SYMBOL(csum_tcpudp_nofold);
#endif
--
2.0.1
^ permalink raw reply related [flat|nested] 4+ messages in thread
* Re: [PATCH v2] lib/checksum.c: fix carry in csum_tcpudp_nofold
2015-01-28 9:58 [PATCH v2] lib/checksum.c: fix carry in csum_tcpudp_nofold Karl Beldan
@ 2015-01-28 13:04 ` Eric Dumazet
2015-01-29 6:32 ` David Miller
1 sibling, 0 replies; 4+ messages in thread
From: Eric Dumazet @ 2015-01-28 13:04 UTC (permalink / raw)
To: Karl Beldan
Cc: Karl Beldan, Al Viro, Arnd Bergmann, Mike Frysinger, netdev,
linux-kernel, stable
On Wed, 2015-01-28 at 10:58 +0100, Karl Beldan wrote:
> The carry from the 64->32bits folding was dropped, e.g with:
> saddr=0xFFFFFFFF daddr=0xFF0000FF len=0xFFFF proto=0 sum=1,
> csum_tcpudp_nofold returned 0 instead of 1.
>
> Signed-off-by: Karl Beldan <karl.beldan@rivierawaves.com>
> Cc: Al Viro <viro@ZenIV.linux.org.uk>
> Cc: Eric Dumazet <eric.dumazet@gmail.com>
> Cc: Arnd Bergmann <arnd@arndb.de>
> Cc: Mike Frysinger <vapier@gentoo.org>
> Cc: netdev@vger.kernel.org
> Cc: linux-kernel@vger.kernel.org
> Cc: stable@vger.kernel.org
> ---
> lib/checksum.c | 12 ++++++++++--
> 1 file changed, 10 insertions(+), 2 deletions(-)
Signed-off-by: Eric Dumazet <edumazet@google.com>
Thanks !
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH v2] lib/checksum.c: fix carry in csum_tcpudp_nofold
2015-01-28 9:58 [PATCH v2] lib/checksum.c: fix carry in csum_tcpudp_nofold Karl Beldan
2015-01-28 13:04 ` Eric Dumazet
@ 2015-01-29 6:32 ` David Miller
2015-01-29 8:55 ` Karl Beldan
1 sibling, 1 reply; 4+ messages in thread
From: David Miller @ 2015-01-29 6:32 UTC (permalink / raw)
To: karl.beldan
Cc: karl.beldan, viro, eric.dumazet, arnd, vapier, netdev,
linux-kernel, stable
From: Karl Beldan <karl.beldan@gmail.com>
Date: Wed, 28 Jan 2015 10:58:11 +0100
> The carry from the 64->32bits folding was dropped, e.g with:
> saddr=0xFFFFFFFF daddr=0xFF0000FF len=0xFFFF proto=0 sum=1,
> csum_tcpudp_nofold returned 0 instead of 1.
>
> Signed-off-by: Karl Beldan <karl.beldan@rivierawaves.com>
Applied, thanks.
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH v2] lib/checksum.c: fix carry in csum_tcpudp_nofold
2015-01-29 6:32 ` David Miller
@ 2015-01-29 8:55 ` Karl Beldan
0 siblings, 0 replies; 4+ messages in thread
From: Karl Beldan @ 2015-01-29 8:55 UTC (permalink / raw)
To: David Miller
Cc: karl.beldan, viro, eric.dumazet, arnd, vapier, netdev,
linux-kernel, stable
On Wed, Jan 28, 2015 at 10:32:49PM -0800, David Miller wrote:
> From: Karl Beldan <karl.beldan@gmail.com>
> Date: Wed, 28 Jan 2015 10:58:11 +0100
>
> > The carry from the 64->32bits folding was dropped, e.g with:
> > saddr=0xFFFFFFFF daddr=0xFF0000FF len=0xFFFF proto=0 sum=1,
> > csum_tcpudp_nofold returned 0 instead of 1.
> >
> > Signed-off-by: Karl Beldan <karl.beldan@rivierawaves.com>
>
> Applied, thanks.
Fengguang's robot reported I managed to break the build, this occurs
when using non-generic do_csum and generic csum_tcpudp_nofold.
I guess a v3 is irrelevant now, should I send another patch for the
build fix only ? Sorry for that.
Karl
^ permalink raw reply [flat|nested] 4+ messages in thread
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2015-01-28 9:58 [PATCH v2] lib/checksum.c: fix carry in csum_tcpudp_nofold Karl Beldan
2015-01-28 13:04 ` Eric Dumazet
2015-01-29 6:32 ` David Miller
2015-01-29 8:55 ` Karl Beldan
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