Re: [Xen-devel] [PATCH 04/19] xen/mce: remove unused x86_mcinfo_add()

[Haozhong Zhang <haozhong.zhang@xxxxxxxxx>]

On 02/17/17 02:55 -0700, Jan Beulich wrote:
> >>> On 17.02.17 at 07:39, <haozhong.zhang@xxxxxxxxx> wrote:
> > Signed-off-by: Haozhong Zhang <haozhong.zhang@xxxxxxxxx>
> 
> Not sure here, I can't imagine the function being here without
> reason, even if the plans perhaps never got carried out. Could
> you please identify in the commit message here whether there
> ever were callers (and if so, when the last one went away) or
> what commit introduced the function without any users?
>

The commit that removed the last uses of x86_mcinfo_add() is

commit 9d13fd9fd320a7740c6446c048ff6a2990095966
Author: Keir Fraser <keir.fraser@xxxxxxxxxx>
Date:   Mon Jun 7 15:46:48 2010 +0100

    x86 mce: Change the method to get the extended MCA information.
    
    Several changes to get the extended MCA information:
    a) Use the x86_mcinfo_reserve in mcinfo_extended to reserve buffer
    from
       mc_info, instead of using the stack
    b) For intel's extended MSR, we don't need write them one
       by one as the MSR are continous
    c) We don't need enum mca_extinfo, since we can consider
       the extended MSR as either per bank, or global. Currently
       we add a hook in global data collection, and didn't call
       register intel_get_extended_msrs as callback. Later that
       hook can be replaced by cleaner way
    
    Signed-off-by: Jiang, Yunhong <yunhong.jiang@xxxxxxxx>

Specially, it's a) in that commit that intended to directly update the
buffer reserved by x86_mcinfo_reserve(), instead of updating another
buffer and using x86_mcinfo_add() to copy it to the buffer reserved by
x86_mcinfo_reserve(). It looks that x86_mcinfo_add() was deprecated by
that commit, so it's reasonable to remove it.

> > --- a/xen/arch/x86/cpu/mcheck/mce.h
> > +++ b/xen/arch/x86/cpu/mcheck/mce.h
> > @@ -146,7 +146,6 @@ typedef struct mcinfo_extended *(*x86_mce_callback_t)
> >      (struct mc_info *, uint16_t, uint64_t);
> >  extern void x86_mce_callback_register(x86_mce_callback_t);
> >  
> > -void *x86_mcinfo_add(struct mc_info *mi, void *mcinfo);
> >  void *x86_mcinfo_reserve(struct mc_info *mi, int size);
> >  void x86_mcinfo_dump(struct mc_info *mi);
> 
> There's a comment earlier in this file which would need adjustment
> too. Maybe that also helps understand if the function would better
> be left in place ...
> 
I'll update the commit if we decide to remove this function.

Thanks,
Haozhong

_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxx
https://lists.xen.org/xen-devel