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authorLinus Torvalds <torvalds@linux-foundation.org>2012-04-16 18:34:12 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2012-04-16 18:34:12 -0700
commitcdd5983063cadf40db63117f4a299881b3bb71c1 (patch)
tree3acf64aaeeceb1e2e3b50749356c3cd05348e1a9 /drivers/block/virtio_blk.c
parenta6cb9ee7cabe68002c3f2ab07224ea27d2617cf1 (diff)
parent3ccc9372ed0fab33d20f10be3c1efd5776ff5913 (diff)
Merge tag 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mst/vhost
Pull virtio fixes from Michael S. Tsirkin: "Here are some virtio fixes for 3.4: a test build fix, a patch by Ren fixing naming for systems with a massive number of virtio blk devices, and balloon fixes for powerpc by David Gibson. There was some discussion about Ren's patch for virtio disc naming: some people wanted to move the legacy name mangling function to the block core. But there's no concensus on that yet, and we can always deduplicate later. Added comments in the hope that this will stop people from copying this legacy naming scheme into future drivers." * tag 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mst/vhost: virtio_balloon: fix handling of PAGE_SIZE != 4k virtio_balloon: Fix endian bug virtio_blk: helper function to format disk names tools/virtio: fix up vhost/test module build
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 0e4ef3de9d5..0d39f2f4294 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);