Partial revert of mainline removal of deprecated sysfs interface for 13568528

Jan. 06, 2012
Oracle bug 13568528
Patch written by Andrew Thomas
Ported by Chuck Anderson

This patch partialy reverts the removal in mainline of a deprecated sysfs
interface needed by the OVM3.0.4 UEK2 based dom0 kernel when it is used
to install OVM3.0.4

Comments from Andrew:

The problem is that in newer kernels, even with the
CONFIG_SYSFS_DEPRECATED[_V2] flags set, some nodes have been removed so to
tools looking in sysfs, pieces are missing.  This breaks anaconda (actually
kudzu) for us.  For OVM3 we use the dom0 kernel as the install kernel, so we
need UEK2 to provide the right "shape" sysfs.  This isn't an issue for OL
because you use the old RHEL kernel to install UEK1/2].  That said, this
issue affects more than us.  As Joe Jin points out, bug 13100678, required
kudzu fixes for eth devices.  Arguably the OVM3 anaconda issue can also be
fixed in kudzu, but what no one knows is if the missing sysfs nodes are
symptoms of a wider set of tools related problems and therefore whether the
correct fix is to revert sysfs changes in UEK2 so that the sysfs it presents
is isomorphic to what 2.6.18 based kernels provide.

A "better" set of tools would be from 6uX, but in order to get those
installed/upgraded on OVM3 is not a trivial task because the system customers
have already installed is 5u5 based.  We have other tools in dom0 [eg our
agent] which "know" about the old flavour of sysfs and these would need
porting.  You either change the kernel OR you change all the tools that rely
on sysfs... the problem is that customers can install there own tools on OL5.

Signed-off-by: Chuck Anderson <chuck.anderson@oracle.com>

diff --git a/drivers/base/class.c b/drivers/base/class.c
index 4f1df2e8fd744b837552e5cea24c14499086cb88..6fcb15b3f73f841d0b73437cd99e76bbaa46a7a2 100644 (file)
--- a/drivers/base/class.c
+++ b/drivers/base/class.c
@@ -276,6 +276,25 @@ void class_destroy(struct class *cls)
        class_unregister(cls);
 }
 
+#ifdef CONFIG_SYSFS_DEPRECATED
+char *make_class_name(const char *name, struct kobject *kobj)
+{
+       char *class_name;
+       int size;
+
+       size = strlen(name) + strlen(kobject_name(kobj)) + 2;
+
+       class_name = kmalloc(size, GFP_KERNEL);
+       if (!class_name)
+               return NULL;
+
+       strcpy(class_name, name);
+       strcat(class_name, ":");
+       strcat(class_name, kobject_name(kobj));
+       return class_name;
+}
+#endif
+
 /**
  * class_dev_iter_init - initialize class device iterator
  * @iter: class iterator to initialize

diff --git a/drivers/base/core.c b/drivers/base/core.c
index 78445f40c43088468260d1f51feb339bdcb7f752..7c2bfbf27c689173f73bd54f977dd865fd721706 100644 (file)
--- a/drivers/base/core.c
+++ b/drivers/base/core.c
@@ -759,6 +759,29 @@ static int device_add_class_symlinks(struct device *dev)
                        goto out_subsys;
        }
 
+#ifdef CONFIG_SYSFS_DEPRECATED
+       if (dev->parent && device_is_not_partition(dev)) {
+               struct device *parent = dev->parent;
+               char *class_name;
+
+               /*
+                * stacked class devices have the 'device' link
+                * pointing to the bus device instead of the parent
+                */
+               while (parent->class && !parent->bus && parent->parent)
+                       parent = parent->parent;
+
+               class_name = make_class_name(dev->class->name,
+                                               &dev->kobj);
+               if (class_name)
+                       error = sysfs_create_link(&dev->parent->kobj,
+                                               &dev->kobj, class_name);
+               kfree(class_name);
+               if (error)
+                       goto out_subsys;
+       }
+#endif
+
 #ifdef CONFIG_BLOCK
        /* /sys/block has directories and does not need symlinks */
        if (sysfs_deprecated && dev->class == &block_class)
@@ -787,6 +810,18 @@ static void device_remove_class_symlinks(struct device *dev)
        if (!dev->class)
                return;
 
+#ifdef CONFIG_SYSFS_DEPRECATED
+       if (dev->parent && device_is_not_partition(dev)) {
+               char *class_name;
+
+               class_name = make_class_name(dev->class->name, &dev->kobj);
+               if (class_name) {
+                       sysfs_remove_link(&dev->parent->kobj, class_name);
+                       kfree(class_name);
+               }
+               sysfs_remove_link(&dev->kobj, "device");
+       }
+#endif
        if (dev->parent && device_is_not_partition(dev))
                sysfs_remove_link(&dev->kobj, "device");
        sysfs_remove_link(&dev->kobj, "subsystem");