Merge git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux-2.6

[cascardo/linux.git] / fs / sysfs / file.c

diff --git a/fs/sysfs/file.c b/fs/sysfs/file.c
index 98b0910..0e637ad 100644 (file)
--- a/fs/sysfs/file.c
+++ b/fs/sysfs/file.c
@@ -13,8 +13,7 @@
 
 #include "sysfs.h"
 
-#define to_subsys(k) container_of(k,struct subsystem,kset.kobj)
-#define to_sattr(a) container_of(a,struct subsys_attribute,attr)
+#define to_sattr(a) container_of(a,struct subsys_attribute, attr)
 
 /*
  * Subsystem file operations.
@@ -24,12 +23,12 @@
 static ssize_t 
 subsys_attr_show(struct kobject * kobj, struct attribute * attr, char * page)
 {
-       struct subsystem * s = to_subsys(kobj);
+       struct kset *kset = to_kset(kobj);
        struct subsys_attribute * sattr = to_sattr(attr);
        ssize_t ret = -EIO;
 
        if (sattr->show)
-               ret = sattr->show(s,page);
+               ret = sattr->show(kset, page);
        return ret;
 }
 
@@ -37,12 +36,12 @@ static ssize_t
 subsys_attr_store(struct kobject * kobj, struct attribute * attr, 
                  const char * page, size_t count)
 {
-       struct subsystem * s = to_subsys(kobj);
+       struct kset *kset = to_kset(kobj);
        struct subsys_attribute * sattr = to_sattr(attr);
        ssize_t ret = -EIO;
 
        if (sattr->store)
-               ret = sattr->store(s,page,count);
+               ret = sattr->store(kset, page, count);
        return ret;
 }
 
@@ -168,12 +167,12 @@ sysfs_read_file(struct file *file, char __user *buf, size_t count, loff_t *ppos)
        ssize_t retval = 0;
 
        down(&buffer->sem);
-       if (buffer->orphaned) {
-               retval = -ENODEV;
-               goto out;
-       }
        if (buffer->needs_read_fill) {
-               if ((retval = fill_read_buffer(file->f_path.dentry,buffer)))
+               if (buffer->orphaned)
+                       retval = -ENODEV;
+               else
+                       retval = fill_read_buffer(file->f_path.dentry,buffer);
+               if (retval)
                        goto out;
        }
        pr_debug("%s: count = %zd, ppos = %lld, buf = %s\n",
@@ -501,6 +500,30 @@ int sysfs_create_file(struct kobject * kobj, const struct attribute * attr)
 }
 
 
+/**
+ * sysfs_add_file_to_group - add an attribute file to a pre-existing group.
+ * @kobj: object we're acting for.
+ * @attr: attribute descriptor.
+ * @group: group name.
+ */
+int sysfs_add_file_to_group(struct kobject *kobj,
+               const struct attribute *attr, const char *group)
+{
+       struct dentry *dir;
+       int error;
+
+       dir = lookup_one_len(group, kobj->dentry, strlen(group));
+       if (IS_ERR(dir))
+               error = PTR_ERR(dir);
+       else {
+               error = sysfs_add_file(dir, attr, SYSFS_KOBJ_ATTR);
+               dput(dir);
+       }
+       return error;
+}
+EXPORT_SYMBOL_GPL(sysfs_add_file_to_group);
+
+
 /**
  * sysfs_update_file - update the modified timestamp on an object attribute.
  * @kobj: object we're acting for.
@@ -586,6 +609,88 @@ void sysfs_remove_file(struct kobject * kobj, const struct attribute * attr)
 }
 
 
+/**
+ * sysfs_remove_file_from_group - remove an attribute file from a group.
+ * @kobj: object we're acting for.
+ * @attr: attribute descriptor.
+ * @group: group name.
+ */
+void sysfs_remove_file_from_group(struct kobject *kobj,
+               const struct attribute *attr, const char *group)
+{
+       struct dentry *dir;
+
+       dir = lookup_one_len(group, kobj->dentry, strlen(group));
+       if (!IS_ERR(dir)) {
+               sysfs_hash_and_remove(dir, attr->name);
+               dput(dir);
+       }
+}
+EXPORT_SYMBOL_GPL(sysfs_remove_file_from_group);
+
+struct sysfs_schedule_callback_struct {
+       struct kobject          *kobj;
+       void                    (*func)(void *);
+       void                    *data;
+       struct module           *owner;
+       struct work_struct      work;
+};
+
+static void sysfs_schedule_callback_work(struct work_struct *work)
+{
+       struct sysfs_schedule_callback_struct *ss = container_of(work,
+                       struct sysfs_schedule_callback_struct, work);
+
+       (ss->func)(ss->data);
+       kobject_put(ss->kobj);
+       module_put(ss->owner);
+       kfree(ss);
+}
+
+/**
+ * sysfs_schedule_callback - helper to schedule a callback for a kobject
+ * @kobj: object we're acting for.
+ * @func: callback function to invoke later.
+ * @data: argument to pass to @func.
+ * @owner: module owning the callback code
+ *
+ * sysfs attribute methods must not unregister themselves or their parent
+ * kobject (which would amount to the same thing).  Attempts to do so will
+ * deadlock, since unregistration is mutually exclusive with driver
+ * callbacks.
+ *
+ * Instead methods can call this routine, which will attempt to allocate
+ * and schedule a workqueue request to call back @func with @data as its
+ * argument in the workqueue's process context.  @kobj will be pinned
+ * until @func returns.
+ *
+ * Returns 0 if the request was submitted, -ENOMEM if storage could not
+ * be allocated, -ENODEV if a reference to @owner isn't available.
+ */
+int sysfs_schedule_callback(struct kobject *kobj, void (*func)(void *),
+               void *data, struct module *owner)
+{
+       struct sysfs_schedule_callback_struct *ss;
+
+       if (!try_module_get(owner))
+               return -ENODEV;
+       ss = kmalloc(sizeof(*ss), GFP_KERNEL);
+       if (!ss) {
+               module_put(owner);
+               return -ENOMEM;
+       }
+       kobject_get(kobj);
+       ss->kobj = kobj;
+       ss->func = func;
+       ss->data = data;
+       ss->owner = owner;
+       INIT_WORK(&ss->work, sysfs_schedule_callback_work);
+       schedule_work(&ss->work);
+       return 0;
+}
+EXPORT_SYMBOL_GPL(sysfs_schedule_callback);
+
+
 EXPORT_SYMBOL_GPL(sysfs_create_file);
 EXPORT_SYMBOL_GPL(sysfs_remove_file);
 EXPORT_SYMBOL_GPL(sysfs_update_file);