Groups | Search | Server Info | Keyboard shortcuts | Login | Register [http] [https] [nntp] [nntps]

Groups > linux.kernel > #1735611

Re: DMA error when sg->offset value is greater than PAGE_SIZE in Intel IOMMU

From Herbert Xu <herbert@gondor.apana.org.au>
Newsgroups linux.kernel
Subject Re: DMA error when sg->offset value is greater than PAGE_SIZE in Intel IOMMU
Date 2017-09-20 10:10 +0200
Message-ID <urIf0-kT-3@gated-at.bofh.it> (permalink)
References <uqeCm-60W-5@gated-at.bofh.it>
Organization Core

Show all headers | View raw

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.

Cheers,
-- 
Email: Herbert Xu <herbert@gondor.apana.org.au>
Home Page: http://gondor.apana.org.au/~herbert/
PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt

Back to linux.kernel | Previous | Next — Previous in thread | Next in thread | Find similar | Unroll thread

Thread

DMA error when sg->offset value is greater than PAGE_SIZE in Intel  IOMMU Harsh Jain <Harsh@chelsio.com> - 2017-09-16 08:20 +0200
  Re: DMA error when sg->offset value is greater than PAGE_SIZE in  Intel IOMMU Herbert Xu <herbert@gondor.apana.org.au> - 2017-09-20 10:10 +0200
    Re: DMA error when sg->offset value is greater than PAGE_SIZE in  Intel IOMMU Robin Murphy <robin.murphy@arm.com> - 2017-09-20 12:20 +0200
      Re: DMA error when sg->offset value is greater than PAGE_SIZE in  Intel IOMMU Harsh Jain <Harsh@chelsio.com> - 2017-09-20 13:30 +0200
      Re: DMA error when sg->offset value is greater than PAGE_SIZE in  Intel IOMMU Casey Leedom <leedom@chelsio.com> - 2017-09-25 19:50 +0200
        Re: DMA error when sg->offset value is greater than PAGE_SIZE in  Intel IOMMU "Raj, Ashok" <ashok.raj@intel.com> - 2017-09-25 20:50 +0200
          Re: DMA error when sg->offset value is greater than PAGE_SIZE in  Intel IOMMU Casey Leedom <leedom@chelsio.com> - 2017-09-25 20:50 +0200
            Re: DMA error when sg->offset value is greater than PAGE_SIZE in  Intel IOMMU Harsh Jain <Harsh@chelsio.com> - 2017-09-26 05:50 +0200
              Re: DMA error when sg->offset value is greater than PAGE_SIZE in  Intel IOMMU Harsh Jain <Harsh@chelsio.com> - 2017-09-26 14:30 +0200
                Re: DMA error when sg->offset value is greater than PAGE_SIZE in  Intel IOMMU Robin Murphy <robin.murphy@arm.com> - 2017-09-26 16:30 +0200
        Re: DMA error when sg->offset value is greater than PAGE_SIZE in  Intel IOMMU Dan Williams <dan.j.williams@intel.com> - 2017-09-25 21:40 +0200
          Re: DMA error when sg->offset value is greater than PAGE_SIZE in  Intel IOMMU Casey Leedom <leedom@chelsio.com> - 2017-09-25 22:10 +0200
            Re: DMA error when sg->offset value is greater than PAGE_SIZE in  Intel IOMMU Dan Williams <dan.j.williams@intel.com> - 2017-09-25 22:20 +0200
              Re: DMA error when sg->offset value is greater than PAGE_SIZE in  Intel IOMMU "Raj, Ashok" <ashok.raj@intel.com> - 2017-09-25 23:50 +0200
                Re: DMA error when sg->offset value is greater than PAGE_SIZE in  Intel IOMMU Casey Leedom <leedom@chelsio.com> - 2017-09-26 01:50 +0200
              Re: DMA error when sg->offset value is greater than PAGE_SIZE in  Intel IOMMU Harsh Jain <Harsh@chelsio.com> - 2017-09-26 15:10 +0200
    Re: DMA error when sg->offset value is greater than PAGE_SIZE in  Intel IOMMU Harsh Jain <Harsh@chelsio.com> - 2017-09-20 13:40 +0200
    Re: DMA error when sg->offset value is greater than PAGE_SIZE in  Intel IOMMU David Woodhouse <dwmw2@infradead.org> - 2017-09-25 20:50 +0200
      Re: DMA error when sg->offset value is greater than PAGE_SIZE in  Intel IOMMU Casey Leedom <leedom@chelsio.com> - 2017-09-25 22:20 +0200
      Re: DMA error when sg->offset value is greater than PAGE_SIZE in  Intel IOMMU Harsh Jain <Harsh@chelsio.com> - 2017-09-26 13:20 +0200

csiph-web