On Tue, Jul 31, 2018 at 06:01:18PM +0800, Wei Wang wrote: > When "nbits = 0", which means no bits to mask, this macro is expected to > return 0, instead of 0xffffffff. This patch changes the macro to return > 0 when there is no bit needs to be masked. > > Signed-off-by: Wei Wang <wei.w.w...@intel.com> > CC: Juan Quintela <quint...@redhat.com> > CC: Dr. David Alan Gilbert <dgilb...@redhat.com> > CC: Peter Xu <pet...@redhat.com>
Reviewed-by: Peter Xu <pet...@redhat.com> Is there any existing path that can trigger this nbits==0? > --- > include/qemu/bitmap.h | 5 ++++- > 1 file changed, 4 insertions(+), 1 deletion(-) > > v1->v2 ChangeLog: > - fix the macro directly, instead of fixing the callers one by one. > > diff --git a/include/qemu/bitmap.h b/include/qemu/bitmap.h > index 509eedd..9372423 100644 > --- a/include/qemu/bitmap.h > +++ b/include/qemu/bitmap.h > @@ -60,7 +60,10 @@ > */ > > #define BITMAP_FIRST_WORD_MASK(start) (~0UL << ((start) & (BITS_PER_LONG - > 1))) > -#define BITMAP_LAST_WORD_MASK(nbits) (~0UL >> (-(nbits) & (BITS_PER_LONG - > 1))) > +#define BITMAP_LAST_WORD_MASK(nbits) \ > +( \ > + nbits ? (~0UL >> (-(nbits) & (BITS_PER_LONG - 1))) : 0 \ > +) > > #define DECLARE_BITMAP(name,bits) \ > unsigned long name[BITS_TO_LONGS(bits)] > -- > 2.7.4 > Regards, -- Peter Xu
