Re: [PATCH] virtio_blk: Add help function to format mass of disks

["Michael S. Tsirkin" <mst@redhat.com>]

On Tue, Apr 10, 2012 at 04:16:10PM +0300, Avi Kivity wrote:
> On 04/10/2012 10:28 AM, Ren Mingxin wrote:
> > The current virtio block's naming algorithm just supports 18278
> > (26^3 + 26^2 + 26) disks. If there are mass of virtio blocks,
> > there will be disks with the same name.
> >
> > Based on commit 3e1a7ff8a0a7b948f2684930166954f9e8e776fe, I add
> > function "virtblk_name_format()" for virtio block to support mass
> > of disks naming.
> >
> > Signed-off-by: Ren Mingxin <renmx@cn.fujitsu.com>
> > ---
> >  drivers/block/virtio_blk.c |   38 ++++++++++++++++++++++++++------------
> >  1 files changed, 26 insertions(+), 12 deletions(-)
> >
> > diff --git a/drivers/block/virtio_blk.c b/drivers/block/virtio_blk.c
> > index c4a60ba..86516c8 100644
> > --- a/drivers/block/virtio_blk.c
> > +++ b/drivers/block/virtio_blk.c
> > @@ -374,6 +374,31 @@ static int init_vq(struct virtio_blk *vblk)
> >  	return err;
> >  }
> >  
> > +static int virtblk_name_format(char *prefix, int index, char *buf, int buflen)
> > +{
> > +	const int base = 'z' - 'a' + 1;
> > +	char *begin = buf + strlen(prefix);
> > +	char *begin = buf + strlen(prefix);
> 
> Duplicate line.
> 
> > +	char *end = buf + buflen;
> > +	char *p;
> > +	int unit;
> > +
> > +	p = end - 1;
> > +	*p = '\0';
> > +	unit = base;
> 
> Why not use 'base' below?  neither unit nor base change.

Yes it's a bit strange, it was the same in Tejun's patch.
Tejun, any idea?

> > +	do {
> > +		if (p == begin)
> > +			return -EINVAL;
> > +		*--p = 'a' + (index % unit);
> > +		index = (index / unit) - 1;
> > +	} while (index >= 0);
> > +
> > +	memmove(begin, p, end - p);
> > +	memcpy(buf, prefix, strlen(prefix));
> > +
> > +	return 0;
> > +}
> > +
> >
> 
> -- 
> error compiling committee.c: too many arguments to function