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SubjectRe: [PATCH] virtio_blk: Add help function to format mass of disks
On 04/10/2012 03:28 PM, 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>

Make sense to me.

Acked-by: Asias He <asias@redhat.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);
> + char *end = buf + buflen;
> + char *p;
> + int unit;
> +
> + p = end - 1;
> + *p = '\0';
> + unit = base;
> + 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;
> +}
> +
> static int __devinit virtblk_probe(struct virtio_device *vdev)
> {
> struct virtio_blk *vblk;
> @@ -442,18 +467,7 @@ static int __devinit virtblk_probe(struct virtio_device *vdev)
>
> q->queuedata = vblk;
>
> - if (index< 26) {
> - sprintf(vblk->disk->disk_name, "vd%c", 'a' + index % 26);
> - } else if (index< (26 + 1) * 26) {
> - sprintf(vblk->disk->disk_name, "vd%c%c",
> - 'a' + index / 26 - 1, 'a' + index % 26);
> - } else {
> - const unsigned int m1 = (index / 26 - 1) / 26 - 1;
> - const unsigned int m2 = (index / 26 - 1) % 26;
> - const unsigned int m3 = index % 26;
> - sprintf(vblk->disk->disk_name, "vd%c%c%c",
> - 'a' + m1, 'a' + m2, 'a' + m3);
> - }
> + virtblk_name_format("vd", index, vblk->disk->disk_name, DISK_NAME_LEN);
>
> vblk->disk->major = major;
> vblk->disk->first_minor = index_to_minor(index);


--
Asias


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