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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 /drivers/base
parent39aba963d937edb20db7d9d93e6dda5d2adfdcdd (diff)
downloadop-kernel-dev-e52eec13cd6b7f30ab19081b387813e03e592ae5.zip
op-kernel-dev-e52eec13cd6b7f30ab19081b387813e03e592ae5.tar.gz
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 'drivers/base')
-rw-r--r--drivers/base/class.c4
-rw-r--r--drivers/base/core.c26
2 files changed, 19 insertions, 11 deletions
diff --git a/drivers/base/class.c b/drivers/base/class.c
index 1078969..9c63a56 100644
--- a/drivers/base/class.c
+++ b/drivers/base/class.c
@@ -184,9 +184,9 @@ int __class_register(struct class *cls, struct lock_class_key *key)
if (!cls->dev_kobj)
cls->dev_kobj = sysfs_dev_char_kobj;
-#if defined(CONFIG_SYSFS_DEPRECATED) && defined(CONFIG_BLOCK)
+#if defined(CONFIG_BLOCK)
/* let the block class directory show up in the root of sysfs */
- if (cls != &block_class)
+ if (!sysfs_deprecated || cls != &block_class)
cp->class_subsys.kobj.kset = class_kset;
#else
cp->class_subsys.kobj.kset = class_kset;
diff --git a/drivers/base/core.c b/drivers/base/core.c
index 6cf9069..f7f906f 100644
--- a/drivers/base/core.c
+++ b/drivers/base/core.c
@@ -26,6 +26,19 @@
#include "base.h"
#include "power/power.h"
+#ifdef CONFIG_SYSFS_DEPRECATED
+#ifdef CONFIG_SYSFS_DEPRECATED_V2
+long sysfs_deprecated = 1;
+#else
+long sysfs_deprecated = 0;
+#endif
+static __init int sysfs_deprecated_setup(char *arg)
+{
+ return strict_strtol(arg, 10, &sysfs_deprecated);
+}
+early_param("sysfs.deprecated", sysfs_deprecated_setup);
+#endif
+
int (*platform_notify)(struct device *dev) = NULL;
int (*platform_notify_remove)(struct device *dev) = NULL;
static struct kobject *dev_kobj;
@@ -617,14 +630,13 @@ static struct kobject *get_device_parent(struct device *dev,
struct kobject *parent_kobj;
struct kobject *k;
-#ifdef CONFIG_SYSFS_DEPRECATED
/* block disks show up in /sys/block */
- if (dev->class == &block_class) {
+ if (sysfs_deprecated && dev->class == &block_class) {
if (parent && parent->class == &block_class)
return &parent->kobj;
return &block_class.p->class_subsys.kobj;
}
-#endif
+
/*
* If we have no parent, we live in "virtual".
* Class-devices with a non class-device as parent, live
@@ -707,11 +719,9 @@ static int device_add_class_symlinks(struct device *dev)
goto out_subsys;
}
-#ifdef CONFIG_SYSFS_DEPRECATED
/* /sys/block has directories and does not need symlinks */
- if (dev->class == &block_class)
+ if (sysfs_deprecated && dev->class == &block_class)
return 0;
-#endif
/* link in the class directory pointing to the device */
error = sysfs_create_link(&dev->class->p->class_subsys.kobj,
@@ -738,10 +748,8 @@ static void device_remove_class_symlinks(struct device *dev)
if (dev->parent && device_is_not_partition(dev))
sysfs_remove_link(&dev->kobj, "device");
sysfs_remove_link(&dev->kobj, "subsystem");
-#ifdef CONFIG_SYSFS_DEPRECATED
- if (dev->class == &block_class)
+ if (sysfs_deprecated && dev->class == &block_class)
return;
-#endif
sysfs_delete_link(&dev->class->p->class_subsys.kobj, &dev->kobj, dev_name(dev));
}
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