Re: [Qemu-block] [PATCH v15 02/21] block: Define BLK_PERM_MAX

[Fam Zheng]

On Wed, 04/26 11:36, Kevin Wolf wrote:
> Am 26.04.2017 um 05:33 hat Fam Zheng geschrieben:
> > This is the order of the largest possible permission.
> > 
> > Signed-off-by: Fam Zheng <address@hidden>
> > ---
> >  include/block/block.h | 2 ++
> >  1 file changed, 2 insertions(+)
> > 
> > diff --git a/include/block/block.h b/include/block/block.h
> > index eb0565d..a798f10 100644
> > --- a/include/block/block.h
> > +++ b/include/block/block.h
> > @@ -224,6 +224,8 @@ enum {
> >      BLK_PERM_ALL                = 0x1f,
> >  };
> >  
> > +#define BLK_PERM_MAX (64 - clz64((uint64_t)BLK_PERM_ALL))
> 
> Contrary to the commit message, this is the number of permission bits in
> use (i.e. one more than the largest possible permission). You're using
> it correctly, though, because your loop condition is i < BLK_PERM_MAX.
> 
> This could use an updated commit message and a comment at the #define at
> least. Ideally a less ambiguous name instead of the commit (because _MAX
> seems to imply what the commit message currently says, not what it
> really is), but I can't think of one.

Good point.

Given it another thought, using BLK_PERM_ALL in the loop condition is as easy.
I'll drop this patch.

Fam