Messages in this thread | | | Date | Sun, 26 Jul 2015 11:11:44 -0700 | Subject | Re: [PATCH v2 25/25] pmem: convert to generic memremap | From | Dan Williams <> |
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On Sun, Jul 26, 2015 at 10:33 AM, Christoph Hellwig <hch@lst.de> wrote: > On Fri, Jul 24, 2015 at 10:40:20PM -0400, Dan Williams wrote: >> Update memremap_pmem() to query the architecture for the mapping type of >> the given persistent memory range and then pass those flags to generic >> memremap(). arch_memremap_pmem_flags() is provided an address range to >> evaluate in the event an arch has a need for different mapping types by >> address range. For example the ACPI NFIT carries EFI mapping types in >> its memory range description table. > > I don't think the pmem driver should look at a arch hook here, please > communicate this through the nvdimm subsystem. > > Btw, looking at these changes I also think the __pmem annotations > are mistake. We might have all kinds of ways to write to pmem, > and as long as we properly flush it we don't need to force it > through the special accessors. This becomes really interesting > for PCI DMA access.
I don't follow. We have __iomem for the cpu mapping of a resource and dma_map() for a PCI device. __pmem works the same and is there to make sure someone doesn't simply de-reference a pointer to pmem and hope that the write is persistent.
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