[PATCH] misc: pass miscdevice through file's private_data

[Tom Van Braeckel <tomvanbraeckel@gmail.com>]

Make the miscdevice accessible through the file's private_data.

Previously, this was done only when an open() operation had been registered.
But it's also useful in other file operations so we pass it on unconditionally.

All drivers that use private_data and misc_register() were checked to ensure
they register an open() operation in order to verify that this improvement
does not break any existing driver that uses the misc subsystem.

Signed-off-by: Tom Van Braeckel <tomvanbraeckel@gmail.com>
---
 drivers/char/misc.c | 11 ++++++++---
 1 file changed, 8 insertions(+), 3 deletions(-)

diff --git a/drivers/char/misc.c b/drivers/char/misc.c
index ffa97d2..d6445de 100644
--- a/drivers/char/misc.c
+++ b/drivers/char/misc.c
@@ -140,12 +140,17 @@ static int misc_open(struct inode * inode, struct file * file)
 			goto fail;
 	}
 
+	/*
+	 * Place the miscdevice in the file's
+	 * private_data so it can be used by the
+	 * file operations, including f_op->open below
+	 */
+	file->private_data = c;
+
 	err = 0;
 	replace_fops(file, new_fops);
-	if (file->f_op->open) {
-		file->private_data = c;
+	if (file->f_op->open)
 		err = file->f_op->open(inode,file);
-	}
 fail:
 	mutex_unlock(&misc_mtx);
 	return err;
-- 
1.9.1