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authorAndi Kleen <ak@linux.intel.com>2010-09-08 16:54:17 +0200
committerGreg Kroah-Hartman <gregkh@suse.de>2010-10-22 10:16:43 -0700
commite52eec13cd6b7f30ab19081b387813e03e592ae5 (patch)
tree7b327e0b9283c578fb10922edcf6e10b3b8fd943 /include/linux/device.h
parent39aba963d937edb20db7d9d93e6dda5d2adfdcdd (diff)
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>
Diffstat (limited to 'include/linux/device.h')
-rw-r--r--include/linux/device.h7
1 files changed, 7 insertions, 0 deletions
diff --git a/include/linux/device.h b/include/linux/device.h
index 516fecacf27b..dd4895313468 100644
--- a/include/linux/device.h
+++ b/include/linux/device.h
@@ -751,4 +751,11 @@ do { \
MODULE_ALIAS("char-major-" __stringify(major) "-" __stringify(minor))
#define MODULE_ALIAS_CHARDEV_MAJOR(major) \
MODULE_ALIAS("char-major-" __stringify(major) "-*")
+
+#ifdef CONFIG_SYSFS_DEPRECATED
+extern long sysfs_deprecated;
+#else
+#define sysfs_deprecated 0
+#endif
+
#endif /* _DEVICE_H_ */