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![Josh Triplett](/assets/img/avatar_default.png)
Nothing outside of fs/sysfs/file.c references this function, so mark it static. Signed-off-by: Josh Triplett <josh@joshtriplett.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
799 lines
20 KiB
C
799 lines
20 KiB
C
/*
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* fs/sysfs/file.c - sysfs regular (text) file implementation
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*
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* Copyright (c) 2001-3 Patrick Mochel
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* Copyright (c) 2007 SUSE Linux Products GmbH
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* Copyright (c) 2007 Tejun Heo <teheo@suse.de>
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*
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* This file is released under the GPLv2.
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*
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* Please see Documentation/filesystems/sysfs.txt for more information.
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*/
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#include <linux/module.h>
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#include <linux/kobject.h>
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#include <linux/kallsyms.h>
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#include <linux/slab.h>
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#include <linux/fsnotify.h>
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#include <linux/namei.h>
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#include <linux/poll.h>
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#include <linux/list.h>
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#include <linux/mutex.h>
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#include <linux/limits.h>
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#include <asm/uaccess.h>
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#include "sysfs.h"
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/*
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* There's one sysfs_buffer for each open file and one
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* sysfs_open_dirent for each sysfs_dirent with one or more open
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* files.
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*
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* filp->private_data points to sysfs_buffer and
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* sysfs_dirent->s_attr.open points to sysfs_open_dirent. s_attr.open
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* is protected by sysfs_open_dirent_lock.
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*/
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static DEFINE_SPINLOCK(sysfs_open_dirent_lock);
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struct sysfs_open_dirent {
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atomic_t refcnt;
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atomic_t event;
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wait_queue_head_t poll;
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struct list_head buffers; /* goes through sysfs_buffer.list */
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};
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struct sysfs_buffer {
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size_t count;
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loff_t pos;
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char * page;
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const struct sysfs_ops * ops;
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struct mutex mutex;
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int needs_read_fill;
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int event;
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struct list_head list;
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};
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/**
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* fill_read_buffer - allocate and fill buffer from object.
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* @dentry: dentry pointer.
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* @buffer: data buffer for file.
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*
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* Allocate @buffer->page, if it hasn't been already, then call the
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* kobject's show() method to fill the buffer with this attribute's
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* data.
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* This is called only once, on the file's first read unless an error
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* is returned.
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*/
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static int fill_read_buffer(struct dentry * dentry, struct sysfs_buffer * buffer)
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{
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struct sysfs_dirent *attr_sd = dentry->d_fsdata;
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struct kobject *kobj = attr_sd->s_parent->s_dir.kobj;
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const struct sysfs_ops * ops = buffer->ops;
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int ret = 0;
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ssize_t count;
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if (!buffer->page)
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buffer->page = (char *) get_zeroed_page(GFP_KERNEL);
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if (!buffer->page)
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return -ENOMEM;
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/* need attr_sd for attr and ops, its parent for kobj */
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if (!sysfs_get_active(attr_sd))
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return -ENODEV;
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buffer->event = atomic_read(&attr_sd->s_attr.open->event);
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count = ops->show(kobj, attr_sd->s_attr.attr, buffer->page);
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sysfs_put_active(attr_sd);
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/*
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* The code works fine with PAGE_SIZE return but it's likely to
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* indicate truncated result or overflow in normal use cases.
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*/
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if (count >= (ssize_t)PAGE_SIZE) {
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print_symbol("fill_read_buffer: %s returned bad count\n",
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(unsigned long)ops->show);
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/* Try to struggle along */
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count = PAGE_SIZE - 1;
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}
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if (count >= 0) {
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buffer->needs_read_fill = 0;
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buffer->count = count;
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} else {
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ret = count;
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}
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return ret;
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}
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/**
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* sysfs_read_file - read an attribute.
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* @file: file pointer.
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* @buf: buffer to fill.
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* @count: number of bytes to read.
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* @ppos: starting offset in file.
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*
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* Userspace wants to read an attribute file. The attribute descriptor
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* is in the file's ->d_fsdata. The target object is in the directory's
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* ->d_fsdata.
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*
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* We call fill_read_buffer() to allocate and fill the buffer from the
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* object's show() method exactly once (if the read is happening from
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* the beginning of the file). That should fill the entire buffer with
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* all the data the object has to offer for that attribute.
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* We then call flush_read_buffer() to copy the buffer to userspace
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* in the increments specified.
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*/
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static ssize_t
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sysfs_read_file(struct file *file, char __user *buf, size_t count, loff_t *ppos)
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{
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struct sysfs_buffer * buffer = file->private_data;
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ssize_t retval = 0;
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mutex_lock(&buffer->mutex);
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if (buffer->needs_read_fill || *ppos == 0) {
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retval = fill_read_buffer(file->f_path.dentry,buffer);
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if (retval)
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goto out;
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}
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pr_debug("%s: count = %zd, ppos = %lld, buf = %s\n",
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__func__, count, *ppos, buffer->page);
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retval = simple_read_from_buffer(buf, count, ppos, buffer->page,
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buffer->count);
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out:
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mutex_unlock(&buffer->mutex);
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return retval;
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}
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/**
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* fill_write_buffer - copy buffer from userspace.
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* @buffer: data buffer for file.
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* @buf: data from user.
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* @count: number of bytes in @userbuf.
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*
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* Allocate @buffer->page if it hasn't been already, then
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* copy the user-supplied buffer into it.
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*/
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static int
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fill_write_buffer(struct sysfs_buffer * buffer, const char __user * buf, size_t count)
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{
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int error;
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if (!buffer->page)
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buffer->page = (char *)get_zeroed_page(GFP_KERNEL);
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if (!buffer->page)
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return -ENOMEM;
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if (count >= PAGE_SIZE)
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count = PAGE_SIZE - 1;
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error = copy_from_user(buffer->page,buf,count);
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buffer->needs_read_fill = 1;
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/* if buf is assumed to contain a string, terminate it by \0,
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so e.g. sscanf() can scan the string easily */
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buffer->page[count] = 0;
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return error ? -EFAULT : count;
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}
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/**
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* flush_write_buffer - push buffer to kobject.
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* @dentry: dentry to the attribute
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* @buffer: data buffer for file.
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* @count: number of bytes
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*
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* Get the correct pointers for the kobject and the attribute we're
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* dealing with, then call the store() method for the attribute,
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* passing the buffer that we acquired in fill_write_buffer().
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*/
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static int
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flush_write_buffer(struct dentry * dentry, struct sysfs_buffer * buffer, size_t count)
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{
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struct sysfs_dirent *attr_sd = dentry->d_fsdata;
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struct kobject *kobj = attr_sd->s_parent->s_dir.kobj;
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const struct sysfs_ops * ops = buffer->ops;
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int rc;
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/* need attr_sd for attr and ops, its parent for kobj */
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if (!sysfs_get_active(attr_sd))
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return -ENODEV;
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rc = ops->store(kobj, attr_sd->s_attr.attr, buffer->page, count);
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sysfs_put_active(attr_sd);
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return rc;
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}
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/**
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* sysfs_write_file - write an attribute.
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* @file: file pointer
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* @buf: data to write
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* @count: number of bytes
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* @ppos: starting offset
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*
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* Similar to sysfs_read_file(), though working in the opposite direction.
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* We allocate and fill the data from the user in fill_write_buffer(),
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* then push it to the kobject in flush_write_buffer().
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* There is no easy way for us to know if userspace is only doing a partial
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* write, so we don't support them. We expect the entire buffer to come
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* on the first write.
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* Hint: if you're writing a value, first read the file, modify only the
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* the value you're changing, then write entire buffer back.
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*/
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static ssize_t
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sysfs_write_file(struct file *file, const char __user *buf, size_t count, loff_t *ppos)
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{
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struct sysfs_buffer * buffer = file->private_data;
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ssize_t len;
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mutex_lock(&buffer->mutex);
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len = fill_write_buffer(buffer, buf, count);
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if (len > 0)
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len = flush_write_buffer(file->f_path.dentry, buffer, len);
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if (len > 0)
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*ppos += len;
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mutex_unlock(&buffer->mutex);
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return len;
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}
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/**
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* sysfs_get_open_dirent - get or create sysfs_open_dirent
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* @sd: target sysfs_dirent
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* @buffer: sysfs_buffer for this instance of open
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*
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* If @sd->s_attr.open exists, increment its reference count;
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* otherwise, create one. @buffer is chained to the buffers
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* list.
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*
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* LOCKING:
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* Kernel thread context (may sleep).
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*
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* RETURNS:
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* 0 on success, -errno on failure.
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*/
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static int sysfs_get_open_dirent(struct sysfs_dirent *sd,
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struct sysfs_buffer *buffer)
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{
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struct sysfs_open_dirent *od, *new_od = NULL;
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retry:
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spin_lock_irq(&sysfs_open_dirent_lock);
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if (!sd->s_attr.open && new_od) {
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sd->s_attr.open = new_od;
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new_od = NULL;
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}
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od = sd->s_attr.open;
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if (od) {
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atomic_inc(&od->refcnt);
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list_add_tail(&buffer->list, &od->buffers);
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}
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spin_unlock_irq(&sysfs_open_dirent_lock);
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if (od) {
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kfree(new_od);
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return 0;
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}
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/* not there, initialize a new one and retry */
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new_od = kmalloc(sizeof(*new_od), GFP_KERNEL);
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if (!new_od)
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return -ENOMEM;
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atomic_set(&new_od->refcnt, 0);
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atomic_set(&new_od->event, 1);
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init_waitqueue_head(&new_od->poll);
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INIT_LIST_HEAD(&new_od->buffers);
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goto retry;
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}
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/**
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* sysfs_put_open_dirent - put sysfs_open_dirent
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* @sd: target sysfs_dirent
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* @buffer: associated sysfs_buffer
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*
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* Put @sd->s_attr.open and unlink @buffer from the buffers list.
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* If reference count reaches zero, disassociate and free it.
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*
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* LOCKING:
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* None.
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*/
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static void sysfs_put_open_dirent(struct sysfs_dirent *sd,
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struct sysfs_buffer *buffer)
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{
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struct sysfs_open_dirent *od = sd->s_attr.open;
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unsigned long flags;
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spin_lock_irqsave(&sysfs_open_dirent_lock, flags);
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list_del(&buffer->list);
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if (atomic_dec_and_test(&od->refcnt))
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sd->s_attr.open = NULL;
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else
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od = NULL;
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spin_unlock_irqrestore(&sysfs_open_dirent_lock, flags);
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kfree(od);
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}
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static int sysfs_open_file(struct inode *inode, struct file *file)
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{
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struct sysfs_dirent *attr_sd = file->f_path.dentry->d_fsdata;
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struct kobject *kobj = attr_sd->s_parent->s_dir.kobj;
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struct sysfs_buffer *buffer;
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const struct sysfs_ops *ops;
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int error = -EACCES;
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/* need attr_sd for attr and ops, its parent for kobj */
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if (!sysfs_get_active(attr_sd))
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return -ENODEV;
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/* every kobject with an attribute needs a ktype assigned */
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if (kobj->ktype && kobj->ktype->sysfs_ops)
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ops = kobj->ktype->sysfs_ops;
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else {
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WARN(1, KERN_ERR "missing sysfs attribute operations for "
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"kobject: %s\n", kobject_name(kobj));
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goto err_out;
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}
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/* File needs write support.
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* The inode's perms must say it's ok,
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* and we must have a store method.
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*/
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if (file->f_mode & FMODE_WRITE) {
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if (!(inode->i_mode & S_IWUGO) || !ops->store)
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goto err_out;
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}
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/* File needs read support.
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* The inode's perms must say it's ok, and we there
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* must be a show method for it.
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*/
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if (file->f_mode & FMODE_READ) {
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if (!(inode->i_mode & S_IRUGO) || !ops->show)
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goto err_out;
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}
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/* No error? Great, allocate a buffer for the file, and store it
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* it in file->private_data for easy access.
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*/
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error = -ENOMEM;
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buffer = kzalloc(sizeof(struct sysfs_buffer), GFP_KERNEL);
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if (!buffer)
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goto err_out;
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mutex_init(&buffer->mutex);
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buffer->needs_read_fill = 1;
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buffer->ops = ops;
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file->private_data = buffer;
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/* make sure we have open dirent struct */
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error = sysfs_get_open_dirent(attr_sd, buffer);
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if (error)
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goto err_free;
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/* open succeeded, put active references */
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sysfs_put_active(attr_sd);
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return 0;
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err_free:
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kfree(buffer);
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err_out:
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sysfs_put_active(attr_sd);
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return error;
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}
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static int sysfs_release(struct inode *inode, struct file *filp)
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{
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struct sysfs_dirent *sd = filp->f_path.dentry->d_fsdata;
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struct sysfs_buffer *buffer = filp->private_data;
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sysfs_put_open_dirent(sd, buffer);
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if (buffer->page)
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free_page((unsigned long)buffer->page);
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kfree(buffer);
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|
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return 0;
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}
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|
|
|
/* Sysfs attribute files are pollable. The idea is that you read
|
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* the content and then you use 'poll' or 'select' to wait for
|
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* the content to change. When the content changes (assuming the
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* manager for the kobject supports notification), poll will
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* return POLLERR|POLLPRI, and select will return the fd whether
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* it is waiting for read, write, or exceptions.
|
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* Once poll/select indicates that the value has changed, you
|
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* need to close and re-open the file, or seek to 0 and read again.
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* Reminder: this only works for attributes which actively support
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* it, and it is not possible to test an attribute from userspace
|
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* to see if it supports poll (Neither 'poll' nor 'select' return
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* an appropriate error code). When in doubt, set a suitable timeout value.
|
|
*/
|
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static unsigned int sysfs_poll(struct file *filp, poll_table *wait)
|
|
{
|
|
struct sysfs_buffer * buffer = filp->private_data;
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|
struct sysfs_dirent *attr_sd = filp->f_path.dentry->d_fsdata;
|
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struct sysfs_open_dirent *od = attr_sd->s_attr.open;
|
|
|
|
/* need parent for the kobj, grab both */
|
|
if (!sysfs_get_active(attr_sd))
|
|
goto trigger;
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|
|
|
poll_wait(filp, &od->poll, wait);
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|
|
|
sysfs_put_active(attr_sd);
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|
|
|
if (buffer->event != atomic_read(&od->event))
|
|
goto trigger;
|
|
|
|
return DEFAULT_POLLMASK;
|
|
|
|
trigger:
|
|
buffer->needs_read_fill = 1;
|
|
return DEFAULT_POLLMASK|POLLERR|POLLPRI;
|
|
}
|
|
|
|
void sysfs_notify_dirent(struct sysfs_dirent *sd)
|
|
{
|
|
struct sysfs_open_dirent *od;
|
|
unsigned long flags;
|
|
|
|
spin_lock_irqsave(&sysfs_open_dirent_lock, flags);
|
|
|
|
od = sd->s_attr.open;
|
|
if (od) {
|
|
atomic_inc(&od->event);
|
|
wake_up_interruptible(&od->poll);
|
|
}
|
|
|
|
spin_unlock_irqrestore(&sysfs_open_dirent_lock, flags);
|
|
}
|
|
EXPORT_SYMBOL_GPL(sysfs_notify_dirent);
|
|
|
|
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, NULL, dir);
|
|
if (sd && attr)
|
|
sd = sysfs_find_dirent(sd, NULL, 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,
|
|
};
|
|
|
|
static int sysfs_attr_ns(struct kobject *kobj, const struct attribute *attr,
|
|
const void **pns)
|
|
{
|
|
struct sysfs_dirent *dir_sd = kobj->sd;
|
|
const struct sysfs_ops *ops;
|
|
const void *ns = NULL;
|
|
int err;
|
|
|
|
if (!dir_sd) {
|
|
WARN(1, KERN_ERR "sysfs: kobject %s without dirent\n",
|
|
kobject_name(kobj));
|
|
return -ENOENT;
|
|
}
|
|
|
|
err = 0;
|
|
if (!sysfs_ns_type(dir_sd))
|
|
goto out;
|
|
|
|
err = -EINVAL;
|
|
if (!kobj->ktype)
|
|
goto out;
|
|
ops = kobj->ktype->sysfs_ops;
|
|
if (!ops)
|
|
goto out;
|
|
if (!ops->namespace)
|
|
goto out;
|
|
|
|
err = 0;
|
|
ns = ops->namespace(kobj, attr);
|
|
out:
|
|
if (err) {
|
|
WARN(1, KERN_ERR "missing sysfs namespace attribute operation for "
|
|
"kobject: %s\n", kobject_name(kobj));
|
|
}
|
|
*pns = ns;
|
|
return err;
|
|
}
|
|
|
|
int sysfs_add_file_mode(struct sysfs_dirent *dir_sd,
|
|
const struct attribute *attr, int type, umode_t amode)
|
|
{
|
|
umode_t mode = (amode & S_IALLUGO) | S_IFREG;
|
|
struct sysfs_addrm_cxt acxt;
|
|
struct sysfs_dirent *sd;
|
|
const void *ns;
|
|
int rc;
|
|
|
|
rc = sysfs_attr_ns(dir_sd->s_dir.kobj, attr, &ns);
|
|
if (rc)
|
|
return rc;
|
|
|
|
sd = sysfs_new_dirent(attr->name, mode, type);
|
|
if (!sd)
|
|
return -ENOMEM;
|
|
|
|
sd->s_ns = ns;
|
|
sd->s_attr.attr = (void *)attr;
|
|
sysfs_dirent_init_lockdep(sd);
|
|
|
|
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: attribute descriptor.
|
|
*/
|
|
|
|
int sysfs_create_file(struct kobject * kobj, const struct attribute * attr)
|
|
{
|
|
BUG_ON(!kobj || !kobj->sd || !attr);
|
|
|
|
return sysfs_add_file(kobj->sd, attr, SYSFS_KOBJ_ATTR);
|
|
|
|
}
|
|
|
|
int sysfs_create_files(struct kobject *kobj, const struct attribute **ptr)
|
|
{
|
|
int err = 0;
|
|
int i;
|
|
|
|
for (i = 0; ptr[i] && !err; i++)
|
|
err = sysfs_create_file(kobj, ptr[i]);
|
|
if (err)
|
|
while (--i >= 0)
|
|
sysfs_remove_file(kobj, ptr[i]);
|
|
return err;
|
|
}
|
|
|
|
/**
|
|
* 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 sysfs_dirent *dir_sd;
|
|
int error;
|
|
|
|
if (group)
|
|
dir_sd = sysfs_get_dirent(kobj->sd, NULL, 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.
|
|
* @kobj: object we're acting for.
|
|
* @attr: attribute descriptor.
|
|
* @mode: file permissions.
|
|
*
|
|
*/
|
|
int sysfs_chmod_file(struct kobject *kobj, const struct attribute *attr,
|
|
umode_t mode)
|
|
{
|
|
struct sysfs_dirent *sd;
|
|
struct iattr newattrs;
|
|
const void *ns;
|
|
int rc;
|
|
|
|
rc = sysfs_attr_ns(kobj, attr, &ns);
|
|
if (rc)
|
|
return rc;
|
|
|
|
mutex_lock(&sysfs_mutex);
|
|
|
|
rc = -ENOENT;
|
|
sd = sysfs_find_dirent(kobj->sd, ns, attr->name);
|
|
if (!sd)
|
|
goto out;
|
|
|
|
newattrs.ia_mode = (mode & S_IALLUGO) | (sd->s_mode & ~S_IALLUGO);
|
|
newattrs.ia_valid = ATTR_MODE;
|
|
rc = sysfs_sd_setattr(sd, &newattrs);
|
|
|
|
out:
|
|
mutex_unlock(&sysfs_mutex);
|
|
return rc;
|
|
}
|
|
EXPORT_SYMBOL_GPL(sysfs_chmod_file);
|
|
|
|
|
|
/**
|
|
* sysfs_remove_file - remove an object attribute.
|
|
* @kobj: object we're acting for.
|
|
* @attr: attribute descriptor.
|
|
*
|
|
* Hash the attribute name and kill the victim.
|
|
*/
|
|
|
|
void sysfs_remove_file(struct kobject * kobj, const struct attribute * attr)
|
|
{
|
|
const void *ns;
|
|
|
|
if (sysfs_attr_ns(kobj, attr, &ns))
|
|
return;
|
|
|
|
sysfs_hash_and_remove(kobj->sd, ns, attr->name);
|
|
}
|
|
|
|
void sysfs_remove_files(struct kobject * kobj, const struct attribute **ptr)
|
|
{
|
|
int i;
|
|
for (i = 0; ptr[i]; i++)
|
|
sysfs_remove_file(kobj, ptr[i]);
|
|
}
|
|
|
|
/**
|
|
* 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, NULL, group);
|
|
else
|
|
dir_sd = sysfs_get(kobj->sd);
|
|
if (dir_sd) {
|
|
sysfs_hash_and_remove(dir_sd, NULL, attr->name);
|
|
sysfs_put(dir_sd);
|
|
}
|
|
}
|
|
EXPORT_SYMBOL_GPL(sysfs_remove_file_from_group);
|
|
|
|
struct sysfs_schedule_callback_struct {
|
|
struct list_head workq_list;
|
|
struct kobject *kobj;
|
|
void (*func)(void *);
|
|
void *data;
|
|
struct module *owner;
|
|
struct work_struct work;
|
|
};
|
|
|
|
static struct workqueue_struct *sysfs_workqueue;
|
|
static DEFINE_MUTEX(sysfs_workq_mutex);
|
|
static LIST_HEAD(sysfs_workq);
|
|
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);
|
|
mutex_lock(&sysfs_workq_mutex);
|
|
list_del(&ss->workq_list);
|
|
mutex_unlock(&sysfs_workq_mutex);
|
|
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,
|
|
* -EAGAIN if a callback has already been scheduled for @kobj.
|
|
*/
|
|
int sysfs_schedule_callback(struct kobject *kobj, void (*func)(void *),
|
|
void *data, struct module *owner)
|
|
{
|
|
struct sysfs_schedule_callback_struct *ss, *tmp;
|
|
|
|
if (!try_module_get(owner))
|
|
return -ENODEV;
|
|
|
|
mutex_lock(&sysfs_workq_mutex);
|
|
list_for_each_entry_safe(ss, tmp, &sysfs_workq, workq_list)
|
|
if (ss->kobj == kobj) {
|
|
module_put(owner);
|
|
mutex_unlock(&sysfs_workq_mutex);
|
|
return -EAGAIN;
|
|
}
|
|
mutex_unlock(&sysfs_workq_mutex);
|
|
|
|
if (sysfs_workqueue == NULL) {
|
|
sysfs_workqueue = create_singlethread_workqueue("sysfsd");
|
|
if (sysfs_workqueue == NULL) {
|
|
module_put(owner);
|
|
return -ENOMEM;
|
|
}
|
|
}
|
|
|
|
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);
|
|
INIT_LIST_HEAD(&ss->workq_list);
|
|
mutex_lock(&sysfs_workq_mutex);
|
|
list_add_tail(&ss->workq_list, &sysfs_workq);
|
|
mutex_unlock(&sysfs_workq_mutex);
|
|
queue_work(sysfs_workqueue, &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_remove_files);
|
|
EXPORT_SYMBOL_GPL(sysfs_create_files);
|