[PATCH] register_blkdev(): don't hand out the LOCAL/EXPERIMENTAL majors

As pointed out in http://bugzilla.kernel.org/show_bug.cgi?id=7922, dynamic
blockdev major allocation can hand out majors which LANANA has defined as
being for local/experimental use.

Cc: Torben Mathiasen <device@lanana.org>
Cc: Greg KH <greg@kroah.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Tomas Klas <tomas.klas@mepatek.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 8 insertions, 0 deletions

diff --git a/block/genhd.c b/block/genhd.c
index 457fdac4c17d..36bd3e12a6d4 100644
--- a/block/genhd.c
+++ b/block/genhd.c
@@ -61,6 +61,14 @@ int register_blkdev(unsigned int major, const char *name)
         /* temporary */
         if (major == 0) {
                 for (index = ARRAY_SIZE(major_names)-1; index > 0; index--) {
+                        /*
+                         * Disallow the LANANA-assigned LOCAL/EXPERIMENTAL
+                         * majors
+                         */
+                        if ((60 <= index && index <= 63) ||
+                                        (120 <= index && index <= 127) ||
+                                        (240 <= index && index <= 254))
+                                continue;
                         if (major_names[index] == NULL)
                                 break;
                 }