Merge branch 'for-2.6.24' of git://git.secretlab.ca/git/linux-2.6-mpc52xx into merge

[cascardo/linux.git] / fs / sysfs / file.c

diff --git a/fs/sysfs/file.c b/fs/sysfs/file.c
index b13ba94..d3be1e7 100644 (file)
--- a/fs/sysfs/file.c
+++ b/fs/sysfs/file.c
@@ -1,5 +1,13 @@
 /*
- * 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>
@@ -62,6 +70,8 @@ static spinlock_t sysfs_open_dirent_lock = SPIN_LOCK_UNLOCKED;
 
 struct sysfs_open_dirent {
        atomic_t                refcnt;
+       atomic_t                event;
+       wait_queue_head_t       poll;
        struct list_head        buffers; /* goes through sysfs_buffer.list */
 };
 
@@ -104,7 +114,7 @@ static int fill_read_buffer(struct dentry * dentry, struct sysfs_buffer * buffer
        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);
@@ -301,6 +311,8 @@ static int sysfs_get_open_dirent(struct sysfs_dirent *sd,
                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;
 }
@@ -443,17 +455,17 @@ static unsigned int sysfs_poll(struct file *filp, poll_table *wait)
 {
        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;
@@ -474,8 +486,17 @@ void sysfs_notify(struct kobject *k, char *dir, char *attr)
        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);