sysfs, kernfs: introduce kernfs_notify()
Introduce kernfs interface to wake up poll(2) which takes and returns
sysfs_dirents.
sysfs_notify_dirent() is renamed to kernfs_notify() and sysfs_notify()
is updated so that it doesn't directly grab sysfs_mutex but acquires
the target sysfs_dirents using sysfs_get_dirent().
sysfs_notify_dirent() is reimplemented as a dumb inline wrapper around
kernfs_notify().
This patch doesn't introduce any behavior changes.
Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
diff --git a/fs/sysfs/file.c b/fs/sysfs/file.c
index 74e3478..a68cbef 100644
--- a/fs/sysfs/file.c
+++ b/fs/sysfs/file.c
@@ -851,7 +851,13 @@
return DEFAULT_POLLMASK|POLLERR|POLLPRI;
}
-void sysfs_notify_dirent(struct sysfs_dirent *sd)
+/**
+ * kernfs_notify - notify a kernfs file
+ * @sd: file to notify
+ *
+ * Notify @sd such that poll(2) on @sd wakes up.
+ */
+void kernfs_notify(struct sysfs_dirent *sd)
{
struct sysfs_open_dirent *od;
unsigned long flags;
@@ -868,22 +874,27 @@
spin_unlock_irqrestore(&sysfs_open_dirent_lock, flags);
}
-EXPORT_SYMBOL_GPL(sysfs_notify_dirent);
+EXPORT_SYMBOL_GPL(kernfs_notify);
void sysfs_notify(struct kobject *k, const char *dir, const char *attr)
{
- struct sysfs_dirent *sd = k->sd;
-
- mutex_lock(&sysfs_mutex);
+ struct sysfs_dirent *sd = k->sd, *tmp;
if (sd && dir)
- sd = sysfs_find_dirent(sd, dir, NULL);
- if (sd && attr)
- sd = sysfs_find_dirent(sd, attr, NULL);
- if (sd)
- sysfs_notify_dirent(sd);
+ sd = sysfs_get_dirent(sd, dir);
+ else
+ sysfs_get(sd);
- mutex_unlock(&sysfs_mutex);
+ if (sd && attr) {
+ tmp = sysfs_get_dirent(sd, attr);
+ sysfs_put(sd);
+ sd = tmp;
+ }
+
+ if (sd) {
+ kernfs_notify(sd);
+ sysfs_put(sd);
+ }
}
EXPORT_SYMBOL_GPL(sysfs_notify);