Hi,
> 2024年8月20日 21:36，Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> 写道：
>
> On Tue, Aug 20, 2024 at 09:19:04PM +0800, Miao Wang wrote:
>> Hi, Greg
>>
>> I saw you have included commit 7697a0fe0154 ("LoongArch: Define
>> __ARCH_WANT_NEW_STAT in unistd.h") in your stable trees, which
>> actually introduced new sys calls newfstatat and fstat to Loongarch.
>
> See the documentation in that commit for why it was done.
Thanks for your explanation. I totally understand the necessity of
re-introducing thees two syscalls. I just wonder whether there is any
limitation on what can be included in to the stable trees. If there
was no limitation, theoretically, I could also maintain a so-called
stable tree by applying all the patches from torvalds' tree, except
those that bumps the version number. Apparently such a "stable" tree
is far from stable.
>
>> I wonder if it is correct to add new syscalls, which actually changes
>> the kernel features, in stable releases, as it might confuse downstream
>> developers because they may assume the existence of a certain feature
>> after a certain version.
>
> Version numbers should never be used to be checked for anything as they
> are only a "moment in time" stamp. They do not reflect features or
> capabilities or anything else.
I agree with you and Cyril on the version numbers, recalling that kernels
on RHEL numbered on 3.10 contains various new features.
> Test for functionality if you want to check for something, that's the
> only way it will ever work on all of the variants of different
> "enterprise" kernels.
Thanks again for your quick reply.
>
> thanks,
>
> greg k-h
