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

From	David Woodhouse <dwmw2@infradead.org>
Newsgroups	linux.kernel
Subject	Re: DMA error when sg->offset value is greater than PAGE_SIZE in Intel IOMMU
Date	2017-09-25 20:50 +0200
Message-ID	<utGC6-1Kz-21@gated-at.bofh.it> (permalink)
References	<urIf0-kT-3@gated-at.bofh.it>
Organization	linux.* mail to news gateway

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On Wed, 2017-09-20 at 16:01 +0800, 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.

Hm? Under what circumstances is the offset permitted to be >
PAGE_SIZE?

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

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