Re: [PATCH] KVM: x86: User mutex guards to eliminate __kvm_x86_vendor_init()

[Nikolay Borisov]

On 30.10.23 г. 18:07 ч., Sean Christopherson wrote:
> On Mon, Oct 30, 2023, Nikolay Borisov wrote:
> > Current separation between (__){0,1}kvm_x86_vendor_init() is superfluos as
>
> superfluous
>
> But this intro is actively misleading.  The double-underscore variant most definitely
> isn't superfluous, e.g. it eliminates the need for gotos reduces the probability
> of incorrect error codes, bugs in the error handling, etc.  It _becomes_ superflous
> after switching to guard(mutex).
>
> IMO, this is one of the instances where the "problem, then solution" appoach is
> counter-productive.  If there are no objections, I'll massage the change log to
> the below when applying (for 6.8, in a few weeks).
>
>    Use the recently introduced guard(mutex) infrastructure acquire and
>    automatically release vendor_module_lock when the guard goes out of scope.
>    Drop the inner __kvm_x86_vendor_init(), its sole purpose was to simplify
>    releasing vendor_module_lock in error paths.
>
>    No functional change intended.

Thanks, I'm fine with this changelog.

> > the the underscore version doesn't have any other callers.
> >
> > Instead, use the newly added cleanup infrastructure to ensure that
> > kvm_x86_vendor_init() holds the vendor_module_lock throughout its
> > exectuion and that in case of error in the middle it's released. No
> > functional changes.