Re: [PATCH v3] drivers/base/node.c: fix userspace break from using bin_attributes for cpumap and cpulist

[Phil Auld]

On Thu, Jul 14, 2022 at 08:59:25AM -0400 Phil Auld wrote:
> On Thu, Jul 14, 2022 at 12:23:01PM +1200 Barry Song wrote:
> > btw, we have a lot of other places which might need this, such as
> > drivers/base/topology.c
> > 
> > so perhaps we can move them to some common place,
> > 
> > #define cpu_bitmap_bytes  (((NR_CPUS >> 1) > PAGE_SIZE) ? NR_CPUS >> 1
> > : PAGE_SIZE)
> > #define cpu_list_bytes  (((NR_CPUS * 7) > PAGE_SIZE) ? NR_CPUS * 7 : PAGE_SIZE)
> > 
> > is include/linux/cpumask.h a good place for it?

drivers/base/base.h does not look like the right place, so I think your cpumask.h idea
is better. I'll put in there and update the topology.c BIN_ATTRs. 

Thanks,
Phil

> 
> My concern is the ones that are breaking actual userspace code. But yes, those
> otherwise have the same 0 size. 
> 
> It seems somewhat specific to drivers/base. Maybe there's a less global place to
> put those closer. I can look and do it this way if that will help get it fixed.
> 
> 
> Cheers,
> Phil
> 
> > 
> > >  /**
> > >   * struct node_access_nodes - Access class device to hold user visible
> > > --
> > > 2.31.1
> > >
> > 
> > Thanks
> > Barry
> > 
> 
> -- 

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