HID: hidraw: fix signaling SIGIO when hidraw reports an event

This patch fixes sending SIGIO from hidraw_report_event by creating a fasync
handler which adds the fasync entry.
Signed-off-by: Andrew Duggan <aduggan@synaptics.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>

drivers/hid/hidraw.c

@@ -295,6 +295,13 @@ static int hidraw_open(struct inode *inode, struct file *file)
 
 }
 
+static int hidraw_fasync(int fd, struct file *file, int on)
+{
+	struct hidraw_list *list = file->private_data;
+
+	return fasync_helper(fd, file, on, &list->fasync);
+}
+
 static int hidraw_release(struct inode * inode, struct file * file)
 {
 	unsigned int minor = iminor(inode);
@@ -438,6 +445,7 @@ static const struct file_operations hidraw_ops = {
 	.open =         hidraw_open,
 	.release =      hidraw_release,
 	.unlocked_ioctl = hidraw_ioctl,
+	.fasync =	hidraw_fasync,
 #ifdef CONFIG_COMPAT
 	.compat_ioctl   = hidraw_ioctl,
 #endif