Skip to content

Commit

Permalink
xen-blkfront: properly name all devices
Browse files Browse the repository at this point in the history
- devices beyond xvdzz didn't get proper names assigned at all
- extended devices with minors not representable within the kernel's
  major/minor bit split spilled into foreign majors

Signed-off-by: Jan Beulich <jbeulich@suse.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
  • Loading branch information
Jan Beulich authored and Konrad Rzeszutek Wilk committed May 11, 2012
1 parent e816b57 commit e77c78c
Showing 1 changed file with 22 additions and 18 deletions.
40 changes: 22 additions & 18 deletions drivers/block/xen-blkfront.c
Original file line number Diff line number Diff line change
Expand Up @@ -526,6 +526,14 @@ static int xen_translate_vdev(int vdevice, int *minor, unsigned int *offset)
return 0;
}

static char *encode_disk_name(char *ptr, unsigned int n)
{
if (n >= 26)
ptr = encode_disk_name(ptr, n / 26 - 1);
*ptr = 'a' + n % 26;
return ptr + 1;
}

static int xlvbd_alloc_gendisk(blkif_sector_t capacity,
struct blkfront_info *info,
u16 vdisk_info, u16 sector_size)
Expand All @@ -536,6 +544,7 @@ static int xlvbd_alloc_gendisk(blkif_sector_t capacity,
unsigned int offset;
int minor;
int nr_parts;
char *ptr;

BUG_ON(info->gd != NULL);
BUG_ON(info->rq != NULL);
Expand All @@ -560,7 +569,11 @@ static int xlvbd_alloc_gendisk(blkif_sector_t capacity,
"emulated IDE disks,\n\t choose an xvd device name"
"from xvde on\n", info->vdevice);
}
err = -ENODEV;
if (minor >> MINORBITS) {
pr_warn("blkfront: %#x's minor (%#x) out of range; ignoring\n",
info->vdevice, minor);
return -ENODEV;
}

if ((minor % nr_parts) == 0)
nr_minors = nr_parts;
Expand All @@ -574,23 +587,14 @@ static int xlvbd_alloc_gendisk(blkif_sector_t capacity,
if (gd == NULL)
goto release;

if (nr_minors > 1) {
if (offset < 26)
sprintf(gd->disk_name, "%s%c", DEV_NAME, 'a' + offset);
else
sprintf(gd->disk_name, "%s%c%c", DEV_NAME,
'a' + ((offset / 26)-1), 'a' + (offset % 26));
} else {
if (offset < 26)
sprintf(gd->disk_name, "%s%c%d", DEV_NAME,
'a' + offset,
minor & (nr_parts - 1));
else
sprintf(gd->disk_name, "%s%c%c%d", DEV_NAME,
'a' + ((offset / 26) - 1),
'a' + (offset % 26),
minor & (nr_parts - 1));
}
strcpy(gd->disk_name, DEV_NAME);
ptr = encode_disk_name(gd->disk_name + sizeof(DEV_NAME) - 1, offset);
BUG_ON(ptr >= gd->disk_name + DISK_NAME_LEN);
if (nr_minors > 1)
*ptr = 0;
else
snprintf(ptr, gd->disk_name + DISK_NAME_LEN - ptr,
"%d", minor & (nr_parts - 1));

gd->major = XENVBD_MAJOR;
gd->first_minor = minor;
Expand Down

0 comments on commit e77c78c

Please sign in to comment.