init/do_mounts.c: add create_dev() failure log

If create_dev() function fails to create the root mount device
(/dev/root), then it goes to panic as root device not found but there is
no printk in this case.  So I have added the log in case it fails to
create the root device.  It will help in debugging.

[akpm@linux-foundation.org: simplify printk(), use pr_emerg(), display errno]
Signed-off-by: Vishnu Pratap Singh <vishnu.ps@samsung.com>
Acked-by: Pavel Machek <pavel@ucw.cz>
Cc: Paul Gortmaker <paul.gortmaker@windriver.com>
Cc: Mike Snitzer <snitzer@redhat.com>
Cc: Dan Ehrenberg <dehrenberg@chromium.org>
Cc: Miklos Szeredi <mszeredi@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 7 insertions, 2 deletions

diff --git a/init/do_mounts.c b/init/do_mounts.c
index a95bbdb2a502..dea5de95c2dd 100644
--- a/init/do_mounts.c
+++ b/init/do_mounts.c
@@ -533,8 +533,13 @@ void __init mount_root(void)
         }
 #endif
 #ifdef CONFIG_BLOCK
-        create_dev("/dev/root", ROOT_DEV);
-        mount_block_root("/dev/root", root_mountflags);
+        {
+                int err = create_dev("/dev/root", ROOT_DEV);
+
+                if (err < 0)
+                        pr_emerg("Failed to create /dev/root: %d\n", err);
+                mount_block_root("/dev/root", root_mountflags);
+        }
 #endif
 }