#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;
}
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_dentry,buffer)))
+ if ((retval = fill_read_buffer(file->f_path.dentry,buffer)))
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.
count = PAGE_SIZE - 1;
error = copy_from_user(buffer->page,buf,count);
buffer->needs_read_fill = 1;
+ /* if buf is assumed to contain a string, terminate it by \0,
+ so e.g. sscanf() can scan the string easily */
+ buffer->page[count] = 0;
return error ? -EFAULT : count;
}
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_dentry, buffer, len);
+ 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_dentry->d_parent);
- struct attribute * attr = to_attr(file->f_dentry);
+ 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_dentry->d_parent);
- struct attribute * attr = to_attr(filp->f_dentry);
+ struct kobject * kobj = to_kobj(filp->f_path.dentry->d_parent);
+ struct attribute * attr = to_attr(filp->f_path.dentry);
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);
static unsigned int sysfs_poll(struct file *filp, poll_table *wait)
{
struct sysfs_buffer * buffer = filp->private_data;
- struct kobject * kobj = to_kobj(filp->f_dentry->d_parent);
- struct sysfs_dirent * sd = filp->f_dentry->d_fsdata;
+ struct kobject * kobj = to_kobj(filp->f_path.dentry->d_parent);
+ struct sysfs_dirent * sd = filp->f_path.dentry->d_fsdata;
int res = 0;
poll_wait(filp, &kobj->poll, wait);
(victim->d_parent->d_inode == dir->d_inode)) {
victim->d_inode->i_mtime = CURRENT_TIME;
fsnotify_modify(victim);
-
- /**
- * Drop reference from initial sysfs_get_dentry().
- */
- dput(victim);
res = 0;
} else
d_drop(victim);
/**
- * Drop the reference acquired from sysfs_get_dentry() above.
+ * Drop the reference acquired from lookup_one_len() above.
*/
dput(victim);
}
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);
}
projects / powerpc.git / blobdiff