Messages in this thread | | | Date | Tue, 5 Jul 2022 10:51:02 -0300 | From | Jason Gunthorpe <> | Subject | Re: [PATCH v7 20/21] PCI/P2PDMA: Introduce pci_mmap_p2pmem() |
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On Tue, Jul 05, 2022 at 09:51:08AM +0200, Christoph Hellwig wrote:
> But what also really matters here: I don't want every user that > wants to be able to mmap a character device to do all this work. > The layering is simply wrong, it needs some character device > based helpers, not be open code everywhere.
I think alot (all?) cases would be happy if the inode was 1:1 with the cdev struct device. I suppose the cdev code would still have to create pseudo fs, but at least that is hidden.
> In fact I'm not even sure this should be a character device, it seems > to fit it way better with the PCI sysfs hierchacy, just like how we > map MMIO resources, which these are anyway. And once it is on sysfs > we do have a uniqueue inode and need none of the pseudofs stuff, and > don't need all the glue code in nvme either.
Shouldn't there be an allocator here? It feels a bit weird that the entire CMB is given to a single process, it is a sharable resource, isn't it?
Jason
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