From: Harsh Jain <Harsh@chelsio.com>
To: Herbert Xu <herbert@gondor.apana.org.au>
Cc: dwmw2@infradead.org, joro@8bytes.org,
linux-crypto@vger.kernel.org, iommu@lists.linux-foundation.org,
linux-kernel@vger.kernel.org, leedom@chelsio.com
Subject: Re: DMA error when sg->offset value is greater than PAGE_SIZE in Intel IOMMU
Date: Wed, 20 Sep 2017 17:00:00 +0530 [thread overview]
Message-ID: <dbc09c67-825b-31ea-df1c-9e6b825aa0b7@chelsio.com> (raw)
In-Reply-To: <20170920080151.GA3348@gondor.apana.org.au>
On 20-09-2017 13:31, Herbert Xu wrote:
> Harsh Jain <Harsh@chelsio.com> wrote:
>> While debugging DMA mapping error in chelsio crypto driver we observed that when scatter/gather list received by driver has some entry with page->offset > 4096 (PAGE_SIZE). It starts giving DMA error. Without IOMMU it works fine.
> This is not a bug. The network stack can and will feed us such
> SG lists.
>
>> 2) It cannot be driver's responsibilty to update received sg entries to adjust offset and page
>> because we are not the only one who directly uses received sg list.
> No the driver must deal with this. Having said that, if we can
> improve our driver helper interface to make this easier then we
> should do that too. What we certainly shouldn't do is to take a
> whack-a-mole approach like this patch does.
Agreed,I added that patch for understanding purpose only. Today I referred other crypto driver for DMA related code. Most of them are using dma_map_sg except QAT. In QAT, They are first updating the Page address using offset then mapping each page in for loop with dma_map_single(0. I will try the same in chelsio driver will see the behavior.
>
> Cheers,
next prev parent reply other threads:[~2017-09-20 11:30 UTC|newest]
Thread overview: 42+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-09-16 6:11 DMA error when sg->offset value is greater than PAGE_SIZE in Intel IOMMU Harsh Jain
2017-09-20 8:01 ` Herbert Xu
2017-09-20 10:12 ` Robin Murphy
2017-09-20 11:20 ` Harsh Jain
2017-09-25 17:46 ` Casey Leedom
2017-09-25 15:54 ` Raj, Ashok
2017-09-25 18:46 ` Casey Leedom
2017-09-26 3:46 ` Harsh Jain
[not found] ` <afa02763-4556-0e14-7d1b-1c044cdc1ff7-ut6Up61K2wZBDgjK7y7TUQ@public.gmane.org>
2017-09-26 12:21 ` Harsh Jain
2017-09-26 14:22 ` Robin Murphy
2017-09-26 14:34 ` Raj, Ashok
2017-09-26 14:40 ` Raj, Ashok
2017-09-26 20:50 ` Casey Leedom
2017-09-26 18:15 ` Robin Murphy
[not found] ` <437a9bd8-d4d6-22ca-1a64-1a3e73f1101a-5wv7dgnIgG8@public.gmane.org>
2017-09-26 16:06 ` Casey Leedom
2017-09-26 16:10 ` Dan Williams
2017-09-27 16:31 ` Casey Leedom
[not found] ` <MWHPR12MB160060436AC70CB5BE8C0C6EC8780-Gy0DoCVfaSVsWITs4OkDoAdYzm3356FpvxpqHgZTriW3zl9H0oFU5g@public.gmane.org>
2017-09-27 17:13 ` Dan Williams
2017-10-01 8:59 ` Christoph Hellwig
2017-09-27 17:18 ` Robin Murphy
[not found] ` <20170927181802.3dcd7efb-h2/QxWiDqNo@public.gmane.org>
2017-09-27 14:48 ` Raj, Ashok
2017-09-27 21:29 ` Casey Leedom
[not found] ` <MWHPR12MB16005D59D7A33F3D5BE43395C8780-Gy0DoCVfaSVsWITs4OkDoAdYzm3356FpvxpqHgZTriW3zl9H0oFU5g@public.gmane.org>
2017-09-27 19:07 ` Raj, Ashok
2017-09-27 22:13 ` Casey Leedom
2017-09-28 5:01 ` Harsh Jain
[not found] ` <MWHPR12MB16007E5363E79173C52BFA19C8780-Gy0DoCVfaSVsWITs4OkDoAdYzm3356FpvxpqHgZTriW3zl9H0oFU5g@public.gmane.org>
2017-09-28 10:33 ` Herbert Xu
[not found] ` <20170928103312.GB8118-lOAM2aK0SrRLBo1qDEOMRrpzq4S04n8Q@public.gmane.org>
2017-09-28 11:11 ` Harsh Jain
2017-09-28 13:38 ` Harsh Jain
2017-09-28 13:05 ` Raj, Ashok
2017-09-29 5:37 ` Harsh Jain
2017-09-27 17:30 ` Casey Leedom
2017-09-26 17:30 ` Casey Leedom
2017-09-25 19:31 ` Dan Williams
[not found] ` <CAPcyv4j3J41eY2eR07nTvo75F0yCbL9bNHM8GmXEFOHDQUuf8Q-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2017-09-25 20:05 ` Casey Leedom
[not found] ` <MWHPR12MB1600948B2F57696189FC7C22C87A0-Gy0DoCVfaSVsWITs4OkDoAdYzm3356FpvxpqHgZTriW3zl9H0oFU5g@public.gmane.org>
2017-09-25 20:11 ` Dan Williams
2017-09-25 19:03 ` Raj, Ashok
2017-09-25 23:41 ` Casey Leedom
2017-09-26 13:04 ` Harsh Jain
2017-09-20 11:30 ` Harsh Jain [this message]
2017-09-25 18:45 ` David Woodhouse
2017-09-25 20:19 ` Casey Leedom
2017-09-26 11:17 ` Harsh Jain
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