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sysfs, kernfs: introduce kernfs_notify()

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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>
This commit is contained in:
Tejun Heo
2013-11-28 14:54:27 -05:00
committed by Greg Kroah-Hartman
parent d19b9846df
commit 024f647117
3 changed files with 30 additions and 15 deletions
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33
fs/sysfs/file.c
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@@ -851,7 +851,13 @@ static unsigned int kernfs_file_poll(struct file *filp, poll_table *wait)
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 @@ void sysfs_notify_dirent(struct sysfs_dirent *sd)
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);