Messages in this thread | | | From | Logan Gunthorpe <> | Date | Tue, 11 May 2021 10:19:01 -0600 | Subject | Re: [PATCH 10/16] dma-mapping: Add flags to dma_map_ops to indicate PCI P2PDMA support |
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On 2021-05-11 10:06 a.m., Don Dutile wrote: > On 4/8/21 1:01 PM, Logan Gunthorpe wrote: >> Add a flags member to the dma_map_ops structure with one flag to >> indicate support for PCI P2PDMA. >> >> Also, add a helper to check if a device supports PCI P2PDMA. >> >> Signed-off-by: Logan Gunthorpe <logang@deltatee.com> >> --- >> include/linux/dma-map-ops.h | 3 +++ >> include/linux/dma-mapping.h | 5 +++++ >> kernel/dma/mapping.c | 18 ++++++++++++++++++ >> 3 files changed, 26 insertions(+) >> >> diff --git a/include/linux/dma-map-ops.h b/include/linux/dma-map-ops.h >> index 51872e736e7b..481892822104 100644 >> --- a/include/linux/dma-map-ops.h >> +++ b/include/linux/dma-map-ops.h >> @@ -12,6 +12,9 @@ >> struct cma; >> >> struct dma_map_ops { >> + unsigned int flags; >> +#define DMA_F_PCI_P2PDMA_SUPPORTED (1 << 0) >> + > I'm not a fan of in-line define's; if we're going to add a flags field to the dma-ops > -- and logically it'd be good to have p2pdma go through the dma-ops struct -- > then let's move this up in front of the dma-ops description.
Already changed for v2.
> And now that the dma-ops struct is being 'opened' for p2pdma, should p2pdma ops be added > to this struct, so all this work can be mimic'd/reflected/leveraged/refactored for CXL, GenZ, etc. p2pdma in (the near?) future?
v2 no longer has a specific op for p2pdma. We are now using dma_map_sgtable() which already has the error return we need.
I think any work to support CXL, GenZ, etc will need to be done when they add their own support. I can't and shouldn't guess at their needs now.
Logan
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