virtio_blk: implement naming for vda-vdz,vdaa-vdzz,vdaaa-vdzzz
Am Freitag, 1. Februar 2008 schrieb Christian Borntraeger:
> Right. I will fix that with an additional patch.
This patch goes on top of the minor number patch. Please let me know if
you want a merged patch:
Currently virtio_blk creates the disk name combinging "vd" with 'a'++.
This will give strange names after vdz. I have implemented names up to
vdzzz - inspired by the sd.c code. That should be sufficient for now.
There is one driver in the kernel (driver/s390/block/dasd_genhd.c) that
implements names from dasda-dasdzzzz allowing even more disks. Maybe
a janitor can come up with a common implementation usable for all kind
of block device drivers.
I have tested this patch with 100 disks - seems to work.
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
diff --git a/drivers/block/virtio_blk.c b/drivers/block/virtio_blk.c
index 559c322..3b1a68d 100644
--- a/drivers/block/virtio_blk.c
+++ b/drivers/block/virtio_blk.c
@@ -9,8 +9,7 @@
#define VIRTIO_MAX_SG (3+MAX_PHYS_SEGMENTS)
#define PART_BITS 4
-static unsigned char virtblk_index = 'a';
-static int major, minor;
+static int major, index;
struct virtio_blk
{
@@ -171,6 +170,11 @@
.getgeo = virtblk_getgeo,
};
+static int index_to_minor(int index)
+{
+ return index << PART_BITS;
+}
+
static int virtblk_probe(struct virtio_device *vdev)
{
struct virtio_blk *vblk;
@@ -178,7 +182,7 @@
u64 cap;
u32 v;
- if (minor >= 1 << MINORBITS)
+ if (index_to_minor(index) >= 1 << MINORBITS)
return -ENOSPC;
vdev->priv = vblk = kmalloc(sizeof(*vblk), GFP_KERNEL);
@@ -217,13 +221,24 @@
goto out_put_disk;
}
- sprintf(vblk->disk->disk_name, "vd%c", virtblk_index++);
+ 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);
+ }
+
vblk->disk->major = major;
- vblk->disk->first_minor = minor;
+ vblk->disk->first_minor = index_to_minor(index);
vblk->disk->private_data = vblk;
vblk->disk->fops = &virtblk_fops;
-
- minor += 1 << PART_BITS;
+ index++;
/* If barriers are supported, tell block layer that queue is ordered */
if (vdev->config->feature(vdev, VIRTIO_BLK_F_BARRIER))