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_ops * ops = buffer->ops;
return ops->store(kobj,attr,buffer->page,count);
}
static int
flush_write(struct dentry *dentry, char *buffer, loff_t offset, size_t count)
{
struct bin_attribute *attr = to_bin_attr(dentry);
struct kobject *kobj = to_kobj(dentry->d_parent);
if (!attr->write)
return -EIO;
return attr->write(kobj, buffer, offset, count);
}
static int
fill_read(struct dentry *dentry, char *buffer, loff_t off, size_t count)
{
struct bin_attribute * attr = to_bin_attr(dentry);
struct kobject * kobj = to_kobj(dentry->d_parent);
if (!attr->read)
return -EIO;
return attr->read(kobj, buffer, off, count);
}
static int mmap(struct file *file, struct vm_area_struct *vma)
{
struct dentry *dentry = file->f_dentry;
struct bin_attribute *attr = to_bin_attr(dentry);
struct kobject *kobj = to_kobj(dentry->d_parent);
if (!attr->mmap)
return -EINVAL;
return attr->mmap(kobj, attr, vma);
}
static int release(struct inode * inode, struct file * file)
{
struct kobject * kobj = to_kobj(file->f_dentry->d_parent);
struct bin_attribute * attr = to_bin_attr(file->f_dentry);
u8 * buffer = file->private_data;
if (kobj)
kobject_put(kobj);
module_put(attr->attr.owner);
kfree(buffer);
return 0;
}
/* 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, as simply seeking and reading
* again will not get new data, or reset the state of 'poll'.
* 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 (Nether 'poll' or '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 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;
int res = 0;
poll_wait(filp, &kobj->poll, wait);
if (buffer->event != atomic_read(&sd->s_event)) {
res = POLLERR|POLLPRI;
buffer->needs_read_fill = 1;
}
return res;
}
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 module * owner = attr->owner;
struct sysfs_buffer * buffer = filp->private_data;
if (kobj)
kobject_put(kobj);
/* After this point, attr should not be accessed. */
module_put(owner);
if (buffer) {
if (buffer->page)
free_page((unsigned long)buffer->page);
kfree(buffer);
}
return 0;
}
/**
* fill_read_buffer - allocate and fill buffer from object.
* @dentry: dentry pointer.
* @buffer: data buffer for file.
*
* 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.
*/
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_ops * ops = buffer->ops;
int ret = 0;
ssize_t count;
if (!buffer->page)
buffer->page = (char *) get_zeroed_page(GFP_KERNEL);
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;
}
