/*
- * file.c - operations for regular (text) files.
+ * fs/sysfs/file.c - sysfs regular (text) file implementation
+ *
+ * Copyright (c) 2001-3 Patrick Mochel
+ * Copyright (c) 2007 SUSE Linux Products GmbH
+ * Copyright (c) 2007 Tejun Heo <teheo@suse.de>
+ *
+ * This file is released under the GPLv2.
+ *
+ * Please see Documentation/filesystems/sysfs.txt for more information.
*/
#include <linux/module.h>
-#include <linux/dnotify.h>
#include <linux/kobject.h>
+#include <linux/kallsyms.h>
+#include <linux/slab.h>
+#include <linux/fsnotify.h>
+#include <linux/namei.h>
+#include <linux/poll.h>
+#include <linux/list.h>
+#include <linux/mutex.h>
+#include <linux/limits.h>
#include <asm/uaccess.h>
-#include <asm/semaphore.h>
#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)
-
-/**
- * Subsystem file operations.
- * These operations allow subsystems to have files that can be
- * read/written.
- */
-static ssize_t
-subsys_attr_show(struct kobject * kobj, struct attribute * attr, char * page)
+/* used in crash dumps to help with debugging */
+static char last_sysfs_file[PATH_MAX];
+void sysfs_printk_last_file(void)
{
- struct subsystem * s = to_subsys(kobj);
- struct subsys_attribute * sattr = to_sattr(attr);
- ssize_t ret = 0;
-
- if (sattr->show)
- ret = sattr->show(s,page);
- return ret;
+ printk(KERN_EMERG "last sysfs file: %s\n", last_sysfs_file);
}
-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 subsys_attribute * sattr = to_sattr(attr);
- ssize_t ret = 0;
-
- if (sattr->store)
- ret = sattr->store(s,page,count);
- return ret;
-}
+/*
+ * There's one sysfs_buffer for each open file and one
+ * sysfs_open_dirent for each sysfs_dirent with one or more open
+ * files.
+ *
+ * filp->private_data points to sysfs_buffer and
+ * sysfs_dirent->s_attr.open points to sysfs_open_dirent. s_attr.open
+ * is protected by sysfs_open_dirent_lock.
+ */
+static DEFINE_SPINLOCK(sysfs_open_dirent_lock);
-static struct sysfs_ops subsys_sysfs_ops = {
- .show = subsys_attr_show,
- .store = subsys_attr_store,
+struct sysfs_open_dirent {
+ atomic_t refcnt;
+ atomic_t event;
+ wait_queue_head_t poll;
+ struct list_head buffers; /* goes through sysfs_buffer.list */
};
-
struct sysfs_buffer {
size_t count;
loff_t pos;
char * page;
struct sysfs_ops * ops;
- struct semaphore sem;
+ struct mutex mutex;
int needs_read_fill;
+ int event;
+ struct list_head list;
};
-
/**
* fill_read_buffer - allocate and fill buffer from object.
* @dentry: dentry pointer.
* 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)
{
- struct attribute * attr = to_attr(dentry);
- struct kobject * kobj = to_kobj(dentry->d_parent);
+ struct sysfs_dirent *attr_sd = dentry->d_fsdata;
+ struct kobject *kobj = attr_sd->s_parent->s_dir.kobj;
struct sysfs_ops * ops = buffer->ops;
int ret = 0;
ssize_t count;
if (!buffer->page)
return -ENOMEM;
- count = ops->show(kobj,attr,buffer->page);
- buffer->needs_read_fill = 0;
- BUG_ON(count > (ssize_t)PAGE_SIZE);
- if (count >= 0)
- buffer->count = count;
- else
- ret = count;
- return ret;
-}
-
+ /* need attr_sd for attr and ops, its parent for kobj */
+ if (!sysfs_get_active_two(attr_sd))
+ return -ENODEV;
-/**
- * flush_read_buffer - push buffer to userspace.
- * @buffer: data buffer for file.
- * @buf: user-passed buffer.
- * @count: number of bytes requested.
- * @ppos: file position.
- *
- * Copy the buffer we filled in fill_read_buffer() to userspace.
- * This is done at the reader's leisure, copying and advancing
- * the amount they specify each time.
- * This may be called continuously until the buffer is empty.
- */
-static int flush_read_buffer(struct sysfs_buffer * buffer, char __user * buf,
- size_t count, loff_t * ppos)
-{
- int error;
+ buffer->event = atomic_read(&attr_sd->s_attr.open->event);
+ count = ops->show(kobj, attr_sd->s_attr.attr, buffer->page);
- if (*ppos > buffer->count)
- return 0;
+ sysfs_put_active_two(attr_sd);
- if (count > (buffer->count - *ppos))
- count = buffer->count - *ppos;
-
- error = copy_to_user(buf,buffer->page + *ppos,count);
- if (!error)
- *ppos += count;
- return error ? -EFAULT : count;
+ /*
+ * The code works fine with PAGE_SIZE return but it's likely to
+ * indicate truncated result or overflow in normal use cases.
+ */
+ if (count >= (ssize_t)PAGE_SIZE) {
+ print_symbol("fill_read_buffer: %s returned bad count\n",
+ (unsigned long)ops->show);
+ /* Try to struggle along */
+ count = PAGE_SIZE - 1;
+ }
+ if (count >= 0) {
+ buffer->needs_read_fill = 0;
+ buffer->count = count;
+ } else {
+ ret = count;
+ }
+ return ret;
}
/**
struct sysfs_buffer * buffer = file->private_data;
ssize_t retval = 0;
- down(&buffer->sem);
- if (buffer->needs_read_fill) {
- if ((retval = fill_read_buffer(file->f_dentry,buffer)))
+ mutex_lock(&buffer->mutex);
+ if (buffer->needs_read_fill || *ppos == 0) {
+ retval = fill_read_buffer(file->f_path.dentry,buffer);
+ if (retval)
goto out;
}
- pr_debug("%s: count = %d, ppos = %lld, buf = %s\n",
- __FUNCTION__,count,*ppos,buffer->page);
- retval = flush_read_buffer(buffer,buf,count,ppos);
+ pr_debug("%s: count = %zd, ppos = %lld, buf = %s\n",
+ __func__, count, *ppos, buffer->page);
+ retval = simple_read_from_buffer(buf, count, ppos, buffer->page,
+ buffer->count);
out:
- up(&buffer->sem);
+ mutex_unlock(&buffer->mutex);
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;
}
/**
* flush_write_buffer - push buffer to kobject.
- * @file: file pointer.
+ * @dentry: dentry to the attribute
* @buffer: data buffer for file.
+ * @count: number of bytes
*
* Get the correct pointers for the kobject and the attribute we're
* dealing with, then call the store() method for the attribute,
* passing the buffer that we acquired in fill_write_buffer().
*/
-static int
+static int
flush_write_buffer(struct dentry * dentry, struct sysfs_buffer * buffer, size_t count)
{
- struct attribute * attr = to_attr(dentry);
- struct kobject * kobj = to_kobj(dentry->d_parent);
+ struct sysfs_dirent *attr_sd = dentry->d_fsdata;
+ struct kobject *kobj = attr_sd->s_parent->s_dir.kobj;
struct sysfs_ops * ops = buffer->ops;
+ int rc;
+
+ /* need attr_sd for attr and ops, its parent for kobj */
+ if (!sysfs_get_active_two(attr_sd))
+ return -ENODEV;
- return ops->store(kobj,attr,buffer->page,count);
+ rc = ops->store(kobj, attr_sd->s_attr.attr, buffer->page, count);
+
+ sysfs_put_active_two(attr_sd);
+
+ return rc;
}
struct sysfs_buffer * buffer = file->private_data;
ssize_t len;
- down(&buffer->sem);
+ mutex_lock(&buffer->mutex);
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;
- up(&buffer->sem);
+ mutex_unlock(&buffer->mutex);
return len;
}
-static int check_perm(struct inode * inode, struct file * file)
+/**
+ * sysfs_get_open_dirent - get or create sysfs_open_dirent
+ * @sd: target sysfs_dirent
+ * @buffer: sysfs_buffer for this instance of open
+ *
+ * If @sd->s_attr.open exists, increment its reference count;
+ * otherwise, create one. @buffer is chained to the buffers
+ * list.
+ *
+ * LOCKING:
+ * Kernel thread context (may sleep).
+ *
+ * RETURNS:
+ * 0 on success, -errno on failure.
+ */
+static int sysfs_get_open_dirent(struct sysfs_dirent *sd,
+ struct sysfs_buffer *buffer)
{
- struct kobject *kobj = sysfs_get_kobject(file->f_dentry->d_parent);
- struct attribute * attr = to_attr(file->f_dentry);
- struct sysfs_buffer * buffer;
- struct sysfs_ops * ops = NULL;
- int error = 0;
-
- if (!kobj || !attr)
- goto Einval;
-
- /* Grab the module reference for this attribute if we have one */
- if (!try_module_get(attr->owner)) {
- error = -ENODEV;
- goto Done;
+ struct sysfs_open_dirent *od, *new_od = NULL;
+
+ retry:
+ spin_lock(&sysfs_open_dirent_lock);
+
+ if (!sd->s_attr.open && new_od) {
+ sd->s_attr.open = new_od;
+ new_od = NULL;
}
- /* if the kobject has no ktype, then we assume that it is a subsystem
- * itself, and use ops for it.
- */
- if (kobj->kset && kobj->kset->ktype)
- ops = kobj->kset->ktype->sysfs_ops;
- else if (kobj->ktype)
- ops = kobj->ktype->sysfs_ops;
+ od = sd->s_attr.open;
+ if (od) {
+ atomic_inc(&od->refcnt);
+ list_add_tail(&buffer->list, &od->buffers);
+ }
+
+ spin_unlock(&sysfs_open_dirent_lock);
+
+ if (od) {
+ kfree(new_od);
+ return 0;
+ }
+
+ /* not there, initialize a new one and retry */
+ new_od = kmalloc(sizeof(*new_od), GFP_KERNEL);
+ if (!new_od)
+ return -ENOMEM;
+
+ atomic_set(&new_od->refcnt, 0);
+ atomic_set(&new_od->event, 1);
+ init_waitqueue_head(&new_od->poll);
+ INIT_LIST_HEAD(&new_od->buffers);
+ goto retry;
+}
+
+/**
+ * sysfs_put_open_dirent - put sysfs_open_dirent
+ * @sd: target sysfs_dirent
+ * @buffer: associated sysfs_buffer
+ *
+ * Put @sd->s_attr.open and unlink @buffer from the buffers list.
+ * If reference count reaches zero, disassociate and free it.
+ *
+ * LOCKING:
+ * None.
+ */
+static void sysfs_put_open_dirent(struct sysfs_dirent *sd,
+ struct sysfs_buffer *buffer)
+{
+ struct sysfs_open_dirent *od = sd->s_attr.open;
+
+ spin_lock(&sysfs_open_dirent_lock);
+
+ list_del(&buffer->list);
+ if (atomic_dec_and_test(&od->refcnt))
+ sd->s_attr.open = NULL;
else
- ops = &subsys_sysfs_ops;
+ od = NULL;
- /* No sysfs operations, either from having no subsystem,
- * or the subsystem have no operations.
- */
- if (!ops)
- goto Eaccess;
+ spin_unlock(&sysfs_open_dirent_lock);
+
+ kfree(od);
+}
+
+static int sysfs_open_file(struct inode *inode, struct file *file)
+{
+ struct sysfs_dirent *attr_sd = file->f_path.dentry->d_fsdata;
+ struct kobject *kobj = attr_sd->s_parent->s_dir.kobj;
+ struct sysfs_buffer *buffer;
+ struct sysfs_ops *ops;
+ int error = -EACCES;
+ char *p;
+
+ p = d_path(&file->f_path, last_sysfs_file, sizeof(last_sysfs_file));
+ if (p)
+ memmove(last_sysfs_file, p, strlen(p) + 1);
+
+ /* need attr_sd for attr and ops, its parent for kobj */
+ if (!sysfs_get_active_two(attr_sd))
+ return -ENODEV;
+
+ /* every kobject with an attribute needs a ktype assigned */
+ if (kobj->ktype && kobj->ktype->sysfs_ops)
+ ops = kobj->ktype->sysfs_ops;
+ else {
+ WARN(1, KERN_ERR "missing sysfs attribute operations for "
+ "kobject: %s\n", kobject_name(kobj));
+ goto err_out;
+ }
/* File needs write support.
* The inode's perms must say it's ok,
* and we must have a store method.
*/
if (file->f_mode & FMODE_WRITE) {
-
if (!(inode->i_mode & S_IWUGO) || !ops->store)
- goto Eaccess;
-
+ goto err_out;
}
/* File needs read support.
*/
if (file->f_mode & FMODE_READ) {
if (!(inode->i_mode & S_IRUGO) || !ops->show)
- goto Eaccess;
+ goto err_out;
}
/* No error? Great, allocate a buffer for the file, and store it
* it in file->private_data for easy access.
*/
- buffer = kmalloc(sizeof(struct sysfs_buffer),GFP_KERNEL);
- if (buffer) {
- memset(buffer,0,sizeof(struct sysfs_buffer));
- init_MUTEX(&buffer->sem);
- buffer->needs_read_fill = 1;
- buffer->ops = ops;
- file->private_data = buffer;
- } else
- error = -ENOMEM;
- goto Done;
-
- Einval:
- error = -EINVAL;
- goto Done;
- Eaccess:
- error = -EACCES;
- module_put(attr->owner);
- Done:
- if (error && kobj)
- kobject_put(kobj);
+ error = -ENOMEM;
+ buffer = kzalloc(sizeof(struct sysfs_buffer), GFP_KERNEL);
+ if (!buffer)
+ goto err_out;
+
+ mutex_init(&buffer->mutex);
+ buffer->needs_read_fill = 1;
+ buffer->ops = ops;
+ file->private_data = buffer;
+
+ /* make sure we have open dirent struct */
+ error = sysfs_get_open_dirent(attr_sd, buffer);
+ if (error)
+ goto err_free;
+
+ /* open succeeded, put active references */
+ sysfs_put_active_two(attr_sd);
+ return 0;
+
+ err_free:
+ kfree(buffer);
+ err_out:
+ sysfs_put_active_two(attr_sd);
return error;
}
-static int sysfs_open_file(struct inode * inode, struct file * filp)
+static int sysfs_release(struct inode *inode, struct file *filp)
{
- return check_perm(inode,filp);
+ struct sysfs_dirent *sd = filp->f_path.dentry->d_fsdata;
+ struct sysfs_buffer *buffer = filp->private_data;
+
+ sysfs_put_open_dirent(sd, buffer);
+
+ if (buffer->page)
+ free_page((unsigned long)buffer->page);
+ kfree(buffer);
+
+ return 0;
}
-static int sysfs_release(struct inode * inode, struct file * filp)
+/* Sysfs attribute files are pollable. The idea is that you read
+ * the content and then you use 'poll' or 'select' to wait for
+ * the content to change. When the content changes (assuming the
+ * manager for the kobject supports notification), poll will
+ * return POLLERR|POLLPRI, and select will return the fd whether
+ * it is waiting for read, write, or exceptions.
+ * Once poll/select indicates that the value has changed, you
+ * need to close and re-open the file, or seek to 0 and read again.
+ * Reminder: this only works for attributes which actively support
+ * it, and it is not possible to test an attribute from userspace
+ * to see if it supports poll (Neither 'poll' nor 'select' return
+ * an appropriate error code). When in doubt, set a suitable timeout value.
+ */
+static unsigned int sysfs_poll(struct file *filp, poll_table *wait)
{
- struct kobject * kobj = to_kobj(filp->f_dentry->d_parent);
- struct attribute * attr = to_attr(filp->f_dentry);
- struct module * owner = attr->owner;
struct sysfs_buffer * buffer = filp->private_data;
+ struct sysfs_dirent *attr_sd = filp->f_path.dentry->d_fsdata;
+ struct sysfs_open_dirent *od = attr_sd->s_attr.open;
- if (kobj)
- kobject_put(kobj);
- /* After this point, attr should not be accessed. */
- module_put(owner);
+ /* need parent for the kobj, grab both */
+ if (!sysfs_get_active_two(attr_sd))
+ goto trigger;
+
+ poll_wait(filp, &od->poll, wait);
+
+ sysfs_put_active_two(attr_sd);
+
+ if (buffer->event != atomic_read(&od->event))
+ goto trigger;
- if (buffer) {
- if (buffer->page)
- free_page((unsigned long)buffer->page);
- kfree(buffer);
- }
return 0;
+
+ trigger:
+ buffer->needs_read_fill = 1;
+ return POLLERR|POLLPRI;
+}
+
+void sysfs_notify_dirent(struct sysfs_dirent *sd)
+{
+ struct sysfs_open_dirent *od;
+
+ spin_lock(&sysfs_open_dirent_lock);
+
+ od = sd->s_attr.open;
+ if (od) {
+ atomic_inc(&od->event);
+ wake_up_interruptible(&od->poll);
+ }
+
+ spin_unlock(&sysfs_open_dirent_lock);
}
+EXPORT_SYMBOL_GPL(sysfs_notify_dirent);
-struct file_operations sysfs_file_operations = {
+void sysfs_notify(struct kobject *k, const char *dir, const char *attr)
+{
+ struct sysfs_dirent *sd = k->sd;
+
+ mutex_lock(&sysfs_mutex);
+
+ if (sd && dir)
+ sd = sysfs_find_dirent(sd, dir);
+ if (sd && attr)
+ sd = sysfs_find_dirent(sd, attr);
+ if (sd)
+ sysfs_notify_dirent(sd);
+
+ mutex_unlock(&sysfs_mutex);
+}
+EXPORT_SYMBOL_GPL(sysfs_notify);
+
+const struct file_operations sysfs_file_operations = {
.read = sysfs_read_file,
.write = sysfs_write_file,
.llseek = generic_file_llseek,
.open = sysfs_open_file,
.release = sysfs_release,
+ .poll = sysfs_poll,
};
-
-int sysfs_add_file(struct dentry * dir, const struct attribute * attr, int type)
+int sysfs_add_file_mode(struct sysfs_dirent *dir_sd,
+ const struct attribute *attr, int type, mode_t amode)
{
- struct sysfs_dirent * parent_sd = dir->d_fsdata;
- umode_t mode = (attr->mode & S_IALLUGO) | S_IFREG;
- int error = 0;
+ umode_t mode = (amode & S_IALLUGO) | S_IFREG;
+ struct sysfs_addrm_cxt acxt;
+ struct sysfs_dirent *sd;
+ int rc;
- down(&dir->d_inode->i_sem);
- error = sysfs_make_dirent(parent_sd, NULL, (void *) attr, mode, type);
- up(&dir->d_inode->i_sem);
+ sd = sysfs_new_dirent(attr->name, mode, type);
+ if (!sd)
+ return -ENOMEM;
+ sd->s_attr.attr = (void *)attr;
- return error;
+ sysfs_addrm_start(&acxt, dir_sd);
+ rc = sysfs_add_one(&acxt, sd);
+ sysfs_addrm_finish(&acxt);
+
+ if (rc)
+ sysfs_put(sd);
+
+ return rc;
+}
+
+
+int sysfs_add_file(struct sysfs_dirent *dir_sd, const struct attribute *attr,
+ int type)
+{
+ return sysfs_add_file_mode(dir_sd, attr, type, attr->mode);
}
/**
* sysfs_create_file - create an attribute file for an object.
* @kobj: object we're creating for.
- * @attr: atrribute descriptor.
+ * @attr: attribute descriptor.
*/
int sysfs_create_file(struct kobject * kobj, const struct attribute * attr)
{
- BUG_ON(!kobj || !kobj->dentry || !attr);
+ BUG_ON(!kobj || !kobj->sd || !attr);
- return sysfs_add_file(kobj->dentry, attr, SYSFS_KOBJ_ATTR);
+ return sysfs_add_file(kobj->sd, attr, SYSFS_KOBJ_ATTR);
}
/**
- * sysfs_update_file - update the modified timestamp on an object attribute.
+ * sysfs_add_file_to_group - add an attribute file to a pre-existing group.
* @kobj: object we're acting for.
* @attr: attribute descriptor.
- *
- * Also call dnotify for the dentry, which lots of userspace programs
- * use.
+ * @group: group name.
*/
-int sysfs_update_file(struct kobject * kobj, const struct attribute * attr)
+int sysfs_add_file_to_group(struct kobject *kobj,
+ const struct attribute *attr, const char *group)
{
- struct dentry * dir = kobj->dentry;
- struct dentry * victim;
- int res = -ENOENT;
-
- down(&dir->d_inode->i_sem);
- victim = sysfs_get_dentry(dir, attr->name);
- if (!IS_ERR(victim)) {
- /* make sure dentry is really there */
- if (victim->d_inode &&
- (victim->d_parent->d_inode == dir->d_inode)) {
- victim->d_inode->i_mtime = CURRENT_TIME;
- dnotify_parent(victim, DN_MODIFY);
-
- /**
- * Drop reference from initial sysfs_get_dentry().
- */
- dput(victim);
- res = 0;
- } else
- d_drop(victim);
-
- /**
- * Drop the reference acquired from sysfs_get_dentry() above.
- */
- dput(victim);
- }
- up(&dir->d_inode->i_sem);
+ struct sysfs_dirent *dir_sd;
+ int error;
- return res;
-}
+ if (group)
+ dir_sd = sysfs_get_dirent(kobj->sd, group);
+ else
+ dir_sd = sysfs_get(kobj->sd);
+
+ if (!dir_sd)
+ return -ENOENT;
+
+ error = sysfs_add_file(dir_sd, attr, SYSFS_KOBJ_ATTR);
+ sysfs_put(dir_sd);
+ return error;
+}
+EXPORT_SYMBOL_GPL(sysfs_add_file_to_group);
/**
* sysfs_chmod_file - update the modified mode value on an object attribute.
*/
int sysfs_chmod_file(struct kobject *kobj, struct attribute *attr, mode_t mode)
{
- struct dentry *dir = kobj->dentry;
- struct dentry *victim;
- struct sysfs_dirent *sd;
- umode_t umode = (mode & S_IALLUGO) | S_IFREG;
- int res = -ENOENT;
-
- down(&dir->d_inode->i_sem);
- victim = sysfs_get_dentry(dir, attr->name);
- if (!IS_ERR(victim)) {
- if (victim->d_inode &&
- (victim->d_parent->d_inode == dir->d_inode)) {
- sd = victim->d_fsdata;
- attr->mode = mode;
- sd->s_mode = umode;
- victim->d_inode->i_mode = umode;
- dput(victim);
- res = 0;
- }
+ struct sysfs_dirent *victim_sd = NULL;
+ struct dentry *victim = NULL;
+ struct inode * inode;
+ struct iattr newattrs;
+ int rc;
+
+ rc = -ENOENT;
+ victim_sd = sysfs_get_dirent(kobj->sd, attr->name);
+ if (!victim_sd)
+ goto out;
+
+ mutex_lock(&sysfs_rename_mutex);
+ victim = sysfs_get_dentry(victim_sd);
+ mutex_unlock(&sysfs_rename_mutex);
+ if (IS_ERR(victim)) {
+ rc = PTR_ERR(victim);
+ victim = NULL;
+ goto out;
+ }
+
+ inode = victim->d_inode;
+
+ mutex_lock(&inode->i_mutex);
+
+ newattrs.ia_mode = (mode & S_IALLUGO) | (inode->i_mode & ~S_IALLUGO);
+ newattrs.ia_valid = ATTR_MODE | ATTR_CTIME;
+ newattrs.ia_ctime = current_fs_time(inode->i_sb);
+ rc = sysfs_setattr(victim, &newattrs);
+
+ if (rc == 0) {
+ fsnotify_change(victim, newattrs.ia_valid);
+ mutex_lock(&sysfs_mutex);
+ victim_sd->s_mode = newattrs.ia_mode;
+ mutex_unlock(&sysfs_mutex);
}
- up(&dir->d_inode->i_sem);
- return res;
+ mutex_unlock(&inode->i_mutex);
+ out:
+ dput(victim);
+ sysfs_put(victim_sd);
+ return rc;
}
EXPORT_SYMBOL_GPL(sysfs_chmod_file);
void sysfs_remove_file(struct kobject * kobj, const struct attribute * attr)
{
- sysfs_hash_and_remove(kobj->dentry,attr->name);
+ sysfs_hash_and_remove(kobj->sd, 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 sysfs_dirent *dir_sd;
+
+ if (group)
+ dir_sd = sysfs_get_dirent(kobj->sd, group);
+ else
+ dir_sd = sysfs_get(kobj->sd);
+ if (dir_sd) {
+ sysfs_hash_and_remove(dir_sd, attr->name);
+ sysfs_put(dir_sd);
+ }
+}
+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);
-
git://ftp.safe.ca / safe / jmp / linux-2.6 / blobdiff