Messages in this thread | | | Date | Tue, 10 Nov 2015 15:53:13 -0500 | From | Linda Knippers <> | Subject | Re: [PATCH 1/4] nvdimm: Add wrapper for IOCTL pass thru. |
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On 11/10/2015 3:27 PM, Dan Williams wrote: > On Tue, Nov 10, 2015 at 11:49 AM, Jerry Hoemann <jerry.hoemann@hpe.com> wrote: >> On Tue, Nov 10, 2015 at 12:51:59PM -0500, Jeff Moyer wrote: >>> Jerry Hoemann <jerry.hoemann@hpe.com> writes: >>> >>>> Add IOCTL type 'P' to denote NVDIMM_TYPE_PASSTHRU. >>> >>> Can't you just make passthrough a separate command? If you actually add >> >> There are multiple conflicting NVDIMM _DSM running around, they >> are "device specific". So, we should plan in general and not just >> for the example DSM that Intel added support for. These DSM have >> over lapping and incompatible function ids. >> >> The Intel example is an example, not standard. They are free to >> change it at will. So, we can't be certain there won't be a >> conflict some time in the future if we try to use their number space. >> >> I'm trying to create a generic pass thru that any vendors can use. Putting >> this in the Intel function number space doesn't make a lot of sense to me. > > It isn't the "Intel" function number space. The fact that they > currently align is just a happy accident.
It's not really a happy accident. Your commit message says it was derived from the Intel spec 'for convenience', which I think is convenient for anything that implements that spec.
We've discussed ways of supporting different command sets with you and determined that this pass-through mechanism was a good approach because it allows multiple different command sets to be support in a generic way. Blending the two flavors (generic pass through and explicit function definitions) is confusing to me.
> The kernel is free to break > the 1:1 ioctl number to DSM function number relationship, and I think > it would make the implementation cleaner in this case.
To me it's less clean and even for your own example spec, less convenient if Intel ever updates that spec.
-- ljk > _______________________________________________ > Linux-nvdimm mailing list > Linux-nvdimm@lists.01.org > https://lists.01.org/mailman/listinfo/linux-nvdimm >
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