From: Dave Jones <davej@redhat.com>
Date: Thu, 23 Jan 2014 23:55:43 +0000 (-0800)
Subject: fs/proc/proc_devtree.c: remove empty /proc/device-tree when no openfirmware exists.
X-Git-Tag: firefly_0821_release~3680^2~19^2~6^2~19
X-Git-Url: http://plrg.eecs.uci.edu/git/?a=commitdiff_plain;h=c90c3b6b054d2472bc654f95b73b0d27e91b0430;p=firefly-linux-kernel-4.4.55.git

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>
(cherry picked from commit c1d867a54d426b45da017fbe8e585f8a3064ce8d)
Signed-off-by: Mark Brown <broonie@kernel.org>
---

diff --git a/fs/proc/proc_devtree.c b/fs/proc/proc_devtree.c
index 106a83570630..9fa215473b1d 100644
--- a/fs/proc/proc_devtree.c
+++ b/fs/proc/proc_devtree.c
@@ -235,6 +235,7 @@ 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;
 	}