Re: [RFC PATCH 04/15] lib/scatterlist: Add flag for indicating P2PDMA segments in an SGL
From: Robin Murphy <robin.murphy@arm.com>
Date: 2020-11-09 14:02:28
Also in:
linux-iommu, linux-mm, linux-nvme, linux-pci, lkml
On 2020-11-09 09:12, Christoph Hellwig wrote:
On Fri, Nov 06, 2020 at 10:00:25AM -0700, Logan Gunthorpe wrote:quoted
We make use of the top bit of the dma_length to indicate a P2PDMA segment.I don't think "we" can. There is nothing limiting the size of a SGL segment.
Right, the story behind ab2cbeb0ed30 ("iommu/dma: Handle SG length
overflow better") comes immediately to mind, for one. If all the P2P
users can agree to be in on the game then by all means implement this in
the P2P code, but I don't think it belongs in the generic top-level
scatterlist API.
Robin.