/*
- * 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>
struct sysfs_open_dirent {
atomic_t refcnt;
+ atomic_t event;
+ wait_queue_head_t poll;
struct list_head buffers; /* goes through sysfs_buffer.list */
};
if (!sysfs_get_active_two(attr_sd))
return -ENODEV;
- buffer->event = atomic_read(&attr_sd->s_event);
+ buffer->event = atomic_read(&attr_sd->s_attr.open->event);
count = ops->show(kobj, attr_sd->s_attr.attr, buffer->page);
sysfs_put_active_two(attr_sd);
- BUG_ON(count > (ssize_t)PAGE_SIZE);
+ /*
+ * The code works fine with PAGE_SIZE return but it's likely to
+ * indicate truncated result or overflow in normal use cases.
+ */
+ BUG_ON(count >= (ssize_t)PAGE_SIZE);
if (count >= 0) {
buffer->needs_read_fill = 0;
buffer->count = count;
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;
}
{
struct sysfs_buffer * buffer = filp->private_data;
struct sysfs_dirent *attr_sd = filp->f_path.dentry->d_fsdata;
- struct kobject *kobj = attr_sd->s_parent->s_dir.kobj;
+ struct sysfs_open_dirent *od = attr_sd->s_attr.open;
/* need parent for the kobj, grab both */
if (!sysfs_get_active_two(attr_sd))
goto trigger;
- poll_wait(filp, &kobj->poll, wait);
+ poll_wait(filp, &od->poll, wait);
sysfs_put_active_two(attr_sd);
- if (buffer->event != atomic_read(&attr_sd->s_event))
+ if (buffer->event != atomic_read(&od->event))
goto trigger;
return 0;
if (sd && attr)
sd = sysfs_find_dirent(sd, attr);
if (sd) {
- atomic_inc(&sd->s_event);
- wake_up_interruptible(&k->poll);
+ 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);
}
mutex_unlock(&sysfs_mutex);
/**
* 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)