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[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [Xen-devel] [PATCH v3 for-next 0/4] xen: Convert __page_to_mfn and _mfn_to_page to use typesafe MFN
On 06/11/17 12:11, Jan Beulich wrote: On 06.11.17 at 12:47, <julien.grall@xxxxxxxxxx> wrote:Hi Jan, On 06/11/17 11:37, Jan Beulich wrote:On 01.11.17 at 15:03, <julien.grall@xxxxxxxxxx> wrote:Most of the users of page_to_mfn and mfn_to_page are either overriding the macros to make them work with mfn_t or use mfn_x/_mfn becaue the rest of the function use mfn_t. So I think it is time to make __page_to_mfn and __mfn_to_page using typesafe MFN.I have to admit that I still find the overall goal confusing: Afaict the double-underscore-prefixed versions exist only to allow easily overriding the non-prefixed ones. Hence the first and foremost goal ought to be to convert everyone to using the non-prefixed versions. Files wanting to avoid the typed forms could then continue to use / be switched to the prefixed ones. What you're doing here is producing a mess: The prefixed versions should never have been touched in the first place. And iirc this was discussed before, with the suggestion to use overrides (for the non-prefixed versions) to limit overall patch size.At the end of the discussion in the previous version, you were happy with the modification done here (see [1]).From the angle looked at it back then I indeed was, but I'm looking at this from a slightly different angle now with the reply above.Overall, I think this is an improvement compare to what we have today. Because we enforce the use of MFN typesafe by default. The developer would have to override the helpers if he wants to to use the non-typesafe version. With your suggestion here, you would just keep the override around even when they are not necessary. They will have to be dropped at some point, so why not now?Why would we keep the overrides in place once no longer needed? All I'm asking for is that the double-underscore prefixed macros be left alone, and the non-prefixed versions be converted to be type-safe by default (with the option to override). That'll allow the prefixed variants to go way altogether once all code was switched to typesafe, no longer requiring any overrides. If you left the double-underscore alone, then you can't convert headers using them to typesafe. This is because they can't use the non-prefixed version as they may be override. So what you are suggesting here is will avoid converting those headers until someone step up and finish to convert all the source to MFN typesafe. Personally, I find quite silly to have to delay that... Cheers, Jan -- Julien Grall _______________________________________________ Xen-devel mailing list Xen-devel@xxxxxxxxxxxxx https://lists.xen.org/xen-devel
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