Merge tag 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mst/vhost

[mv-sheeva.git] / drivers / block / virtio_blk.c

diff --git a/drivers/block/virtio_blk.c b/drivers/block/virtio_blk.c
index 0e4ef3de9d5deb6fab10c5ef0fb5678ec610a3be..0d39f2f4294a3c2587e5c019e39904b3f8440fc2 100644 (file)
--- 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);