#include <linux/kobject.h>
#include <linux/namei.h>
#include <linux/poll.h>
+#include <linux/list.h>
#include <asm/uaccess.h>
#include <asm/semaphore.h>
.store = subsys_attr_store,
};
+/**
+ * add_to_collection - add buffer to a collection
+ * @buffer: buffer to be added
+ * @node: inode of set to add to
+ */
-struct sysfs_buffer {
- size_t count;
- loff_t pos;
- char * page;
- struct sysfs_ops * ops;
- struct semaphore sem;
- int needs_read_fill;
- int event;
-};
+static inline void
+add_to_collection(struct sysfs_buffer *buffer, struct inode *node)
+{
+ struct sysfs_buffer_collection *set = node->i_private;
+ mutex_lock(&node->i_mutex);
+ list_add(&buffer->associates, &set->associates);
+ mutex_unlock(&node->i_mutex);
+}
+
+static inline void
+remove_from_collection(struct sysfs_buffer *buffer, struct inode *node)
+{
+ mutex_lock(&node->i_mutex);
+ list_del(&buffer->associates);
+ mutex_unlock(&node->i_mutex);
+}
/**
* fill_read_buffer - allocate and fill buffer from object.
* Allocate @buffer->page, if it hasn't been already, then call the
* kobject's show() method to fill the buffer with this attribute's
* data.
- * This is called only once, on the file's first read.
+ * This is called only once, on the file's first read unless an error
+ * is returned.
*/
static int fill_read_buffer(struct dentry * dentry, struct sysfs_buffer * buffer)
{
buffer->event = atomic_read(&sd->s_event);
count = ops->show(kobj,attr,buffer->page);
- buffer->needs_read_fill = 0;
BUG_ON(count > (ssize_t)PAGE_SIZE);
- if (count >= 0)
+ if (count >= 0) {
+ buffer->needs_read_fill = 0;
buffer->count = count;
- else
+ } else {
ret = count;
+ }
return ret;
}
down(&buffer->sem);
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",
return retval;
}
-
/**
* fill_write_buffer - copy buffer from userspace.
* @buffer: data buffer for file.
ssize_t len;
down(&buffer->sem);
+ if (buffer->orphaned) {
+ len = -ENODEV;
+ goto out;
+ }
len = fill_write_buffer(buffer, buf, count);
if (len > 0)
len = flush_write_buffer(file->f_path.dentry, buffer, len);
if (len > 0)
*ppos += len;
+out:
up(&buffer->sem);
return len;
}
-static int check_perm(struct inode * inode, struct file * file)
+static int sysfs_open_file(struct inode *inode, struct file *file)
{
struct kobject *kobj = sysfs_get_kobject(file->f_path.dentry->d_parent);
struct attribute * attr = to_attr(file->f_path.dentry);
+ struct sysfs_buffer_collection *set;
struct sysfs_buffer * buffer;
struct sysfs_ops * ops = NULL;
int error = 0;
if (!ops)
goto Eaccess;
+ /* make sure we have a collection to add our buffers to */
+ mutex_lock(&inode->i_mutex);
+ if (!(set = inode->i_private)) {
+ if (!(set = inode->i_private = kmalloc(sizeof(struct sysfs_buffer_collection), GFP_KERNEL))) {
+ error = -ENOMEM;
+ goto Done;
+ } else {
+ INIT_LIST_HEAD(&set->associates);
+ }
+ }
+ mutex_unlock(&inode->i_mutex);
+
/* File needs write support.
* The inode's perms must say it's ok,
* and we must have a store method.
*/
buffer = kzalloc(sizeof(struct sysfs_buffer), GFP_KERNEL);
if (buffer) {
+ INIT_LIST_HEAD(&buffer->associates);
init_MUTEX(&buffer->sem);
buffer->needs_read_fill = 1;
buffer->ops = ops;
+ add_to_collection(buffer, inode);
file->private_data = buffer;
} else
error = -ENOMEM;
error = -EACCES;
module_put(attr->owner);
Done:
- if (error && kobj)
+ if (error)
kobject_put(kobj);
return error;
}
-static int sysfs_open_file(struct inode * inode, struct file * filp)
-{
- return check_perm(inode,filp);
-}
-
static int sysfs_release(struct inode * inode, struct file * filp)
{
struct kobject * kobj = to_kobj(filp->f_path.dentry->d_parent);
struct module * owner = attr->owner;
struct sysfs_buffer * buffer = filp->private_data;
- if (kobj)
- kobject_put(kobj);
+ if (buffer)
+ remove_from_collection(buffer, inode);
+ kobject_put(kobj);
/* After this point, attr should not be accessed. */
module_put(owner);
}
+/**
+ * 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.
void sysfs_remove_file(struct kobject * kobj, const struct attribute * attr)
{
- sysfs_hash_and_remove(kobj->dentry,attr->name);
+ sysfs_hash_and_remove(kobj->dentry, attr->name);
+}
+
+
+/**
+ * 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 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);
+ 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.
+ *
+ * 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.
+ */
+int sysfs_schedule_callback(struct kobject *kobj, void (*func)(void *),
+ void *data)
+{
+ struct sysfs_schedule_callback_struct *ss;
+
+ ss = kmalloc(sizeof(*ss), GFP_KERNEL);
+ if (!ss)
+ return -ENOMEM;
+ kobject_get(kobj);
+ ss->kobj = kobj;
+ ss->func = func;
+ ss->data = data;
+ 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);
projects / powerpc.git / blobdiff