fs/proc/proc_devtree.c: remove empty /proc/device-tree when no openfirmware exists.

Distribution kernels might want to build in support for /proc/device-tree
for kernels that might end up running on hardware that doesn't support
openfirmware.  This results in an empty /proc/device-tree existing.
Remove it if the OFW root node doesn't exist.

This situation actually confuses grub2, resulting in install failures.
grub2 sees the /proc/device-tree and picks the wrong install target cf.
http://bzr.savannah.gnu.org/lh/grub/trunk/grub/annotate/4300/util/grub-install.in#L311
grub should be more robust, but still, leaving an empty proc dir seems
pointless.

Addresses https://bugzilla.redhat.com/show_bug.cgi?id=818378.

Signed-off-by: Dave Jones <davej@redhat.com>
Cc: Al Viro <viro@ZenIV.linux.org.uk>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Josh Boyer <jwboyer@fedoraproject.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/fs/proc/proc_devtree.c b/fs/proc/proc_devtree.c
index c824187251f67acfac50a5f5551e2a165dcf2fff..c82dd5147845d07053fd1fa37398d8c6da2560f5 100644 (file)
--- a/fs/proc/proc_devtree.c
+++ b/fs/proc/proc_devtree.c
@@ -232,6 +232,7 @@ void __init proc_device_tree_init(void)
                return;
        root = of_find_node_by_path("/");
        if (root == NULL) {
+               remove_proc_entry("device-tree", NULL);
                pr_debug("/proc/device-tree: can't find root\n");
                return;
        }