commit e52eec13cd6b7f30ab19081b387813e03e592ae5
author Andi Kleen <ak@linux.intel.com> Wed Sep 08 16:54:17 2010 +0200
committer Greg Kroah-Hartman <gregkh@suse.de> Fri Oct 22 10:16:43 2010 -0700
tree 7b327e0b9283c578fb10922edcf6e10b3b8fd943
parent 39aba963d937edb20db7d9d93e6dda5d2adfdcdd

SYSFS: Allow boot time switching between deprecated and modern sysfs layout

I have some systems which need legacy sysfs due to old tools that are
making assumptions that a directory can never be a symlink to another
directory, and it's a big hazzle to compile separate kernels for them.

This patch turns CONFIG_SYSFS_DEPRECATED into a run time option
that can be switched on/off the kernel command line. This way
the same binary can be used in both cases with just a option
on the command line.

The old CONFIG_SYSFS_DEPRECATED_V2 option is still there to set
the default. I kept the weird name to not break existing
config files.

Also the compat code can be still completely disabled by undefining
CONFIG_SYSFS_DEPRECATED_SWITCH -- just the optimizer takes
care of this now instead of lots of ifdefs. This makes the code
look nicer.

v2: This is an updated version on top of Kay's patch to only
handle the block devices. I tested it on my old systems
and that seems to work.

Cc: axboe@kernel.dk
Signed-off-by: Andi Kleen <ak@linux.intel.com>
Cc: Kay Sievers <kay.sievers@vrfy.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>