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path: root/drivers/block/virtio_blk.c
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Diffstat (limited to 'drivers/block/virtio_blk.c')
-rw-r--r--drivers/block/virtio_blk.c41
1 files changed, 29 insertions, 12 deletions
diff --git a/drivers/block/virtio_blk.c b/drivers/block/virtio_blk.c
index 0e4ef3de9d5d..0d39f2f4294a 100644
--- a/drivers/block/virtio_blk.c
+++ b/drivers/block/virtio_blk.c
@@ -375,6 +375,34 @@ static int init_vq(struct virtio_blk *vblk)
return err;
}
+/*
+ * Legacy naming scheme used for virtio devices. We are stuck with it for
+ * virtio blk but don't ever use it for any new driver.
+ */
+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 *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;
@@ -443,18 +471,7 @@ 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);