| From: |
| FUJITA Tomonori <tomof@acm.org> |
| To: |
| akpm@linux-foundation.org |
| Subject: |
| [PATCH -mm 0/11] fix iommu sg merging problem |
| Date: |
| Wed, 24 Oct 2007 19:47:52 +0900 |
| Message-ID: |
| <67bb10d9f4e9473ddc84d9839114602c1966f19f.tomof@acm.org> |
| Cc: |
| linux-kernel@vger.kernel.org, linux-scsi@vger.kernel.org,
James.Bottomley@SteelEye.com, jens.axboe@oracle.com,
greg@kroah.com, jeff@garzik.org, muli@il.ibm.com, paulus@samba.org,
tony.luck@intel.com, davem@davemloft.net, kyle@parisc-linux.org,
aacraid@adaptec.com, fujita.tomonori@lab.ntt.co.jp |
| Archive‑link: | |
Article |
IOMMUs merges scatter/gather segments without considering a low level
driver's restrictions. The problem is that IOMMUs can't access to the
limitations because they are in request_queue.
This patchset introduces a new structure, device_dma_parameters,
including dma information. A pointer to device_dma_parameters is added
to struct device. The bus specific structures (like pci_dev) includes
device_dma_parameters. Low level drivers can use dma_set_max_seg_size
to tell IOMMUs about the restrictions.
We can move more dma stuff in struct device (like dma_mask) to struct
device_dma_parameters later (needs some cleanups before that).
This includes patches for all the IOMMUs that could merge sg (x86_64,
ppc, IA64, alpha, sparc64, and parisc) though only the ppc patch was
tested. The patches for other IOMMUs are only compile tested.
Thanks to everyone for the comments on the previous submission
to linux-scsi.
This is against 2.6.24-rc1. The same patchset is also available:
git://git.kernel.org/pub/scm/linux/kernel/git/tomo/linux-2.6-misc.git iommu-sg-fixes
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