lkml.org 
[lkml]   [2015]   [Nov]   [10]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [PATCH 1/4] nvdimm: Add wrapper for IOCTL pass thru.
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
>



\
 
 \ /
  Last update: 2015-11-10 22:21    [W:0.112 / U:0.092 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site