On Mon, Apr 23, 2018 at 03:57:22PM +0200, Daniel Kiper wrote:
> On Fri, Apr 20, 2018 at 03:21:30PM +0800, Michael Chang wrote:
> > Rounding up the bufio->block_size to meet power of 2 to facilitate next_buf
> > calcuation in grub_bufio_read.
> >
> > Signed-off-by: Michael Chang <mch...@suse.com>
> > ---
> > grub-core/io/bufio.c | 8 ++++++++
> > 1 file changed, 8 insertions(+)
> >
> > diff --git a/grub-core/io/bufio.c b/grub-core/io/bufio.c
> > index 22438277d..4d66b65a3 100644
> > --- a/grub-core/io/bufio.c
> > +++ b/grub-core/io/bufio.c
> > @@ -61,6 +61,14 @@ grub_bufio_open (grub_file_t io, int size)
> > size = ((io->size > GRUB_BUFIO_MAX_SIZE) ? GRUB_BUFIO_MAX_SIZE :
> > io->size);
> >
> > + /* round up size to power of 2 */
>
> May I ask you to say why here?
OK.
>
> > + if (size & (size - 1))
> > + {
> > + int round_up;
> > + for (round_up = 1; round_up < size; round_up <<= 1);
> > + size = round_up;
> > + }
>
> Please use this (stolen from linux/drivers/md/raid5.c):
> while (size & (size - 1))
> size = (size | (size - 1)) + 1;
Cool. They will be added in upcoming V2 patch.
Thanks,
Michael
>
> Daniel
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