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From: Eric Dumazet <eric.dumazet@gmail.com>
To: Nithin Nayak Sujir <nsujir@broadcom.com>
Cc: davem@davemloft.net, netdev@vger.kernel.org,
	Michael Chan <mchan@broadcom.com>,
	stable@vger.kernel.org
Subject: Re: [PATCH v2 net 2/2] tg3: Fix data corruption on 5725 with TSO
Date: Mon, 13 May 2013 14:40:24 -0700	[thread overview]
Message-ID: <1368481224.13473.124.camel@edumazet-glaptop> (raw)
In-Reply-To: <51915C7D.2000407@broadcom.com>

On Mon, 2013-05-13 at 14:34 -0700, Nithin Nayak Sujir wrote:
> 
> On 05/13/2013 02:14 PM, Eric Dumazet wrote:

> >> +/* Test for TSO DMA buffers that cross into regions which are within MSS bytes
> >> + * of any 4GB boundaries: 4G, 8G, etc
> >> + */
> >> +static inline int tg3_4g_tso_overflow_test(struct tg3 *tp, dma_addr_t mapping,
> >> +					   u32 len, u32 mss)
> >> +{
> >> +	if (tg3_asic_rev(tp) == ASIC_REV_5762 && mss) {
> >> +		u32 base = (u32) mapping & 0xffffffff;
> >> +
> >> +		return ((base + len + (mss & 0x3fff)) < base);
> >> +	}
> >> +	return 0;
> >> +}
> >> +
> >
> > I am curious : Does this condition even triggers ?
> >
> 
> Yes, it's a rare problem to occur and was reported in our lab. After we 
> implemented this fix, the problem didn't happen again.
> 

I just cant figure out which part of the kernel could allocate a
fragment spanning a 4G region.

  reply	other threads:[~2013-05-13 21:40 UTC|newest]

Thread overview: 20+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-05-13 21:04 [PATCH v2 net 0/2] tg3: 2 bugfixes - TSO data corruption and phy power down Nithin Nayak Sujir
2013-05-13 21:04 ` [PATCH v2 net 1/2] tg3: Skip powering down function 0 on certain serdes devices Nithin Nayak Sujir
2013-05-14 18:08   ` Joe Perches
2013-05-14 18:17     ` Nithin Nayak Sujir
2013-05-13 21:04 ` [PATCH v2 net 2/2] tg3: Fix data corruption on 5725 with TSO Nithin Nayak Sujir
2013-05-13 21:14   ` Eric Dumazet
2013-05-13 21:34     ` Nithin Nayak Sujir
2013-05-13 21:40       ` Eric Dumazet [this message]
2013-05-13 21:47         ` Nithin Nayak Sujir
2013-05-13 22:10           ` Eric Dumazet
2013-05-14  8:40           ` David Laight
2013-05-14 15:04             ` Michael Chan
2013-05-14 15:20               ` David Laight
2013-05-14 16:19                 ` Michael Chan
2013-05-14 16:46                   ` Eric Dumazet
2013-05-15  8:56                   ` David Laight
2013-05-15 15:12                     ` Michael Chan
2013-05-15 15:23                       ` Eric Dumazet
2013-05-15 15:51                         ` Michael Chan
2013-05-14 18:32 ` [PATCH v2 net 0/2] tg3: 2 bugfixes - TSO data corruption and phy power down David Miller

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