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

From: Tom Van Braeckel
Date: Thu Dec 04 2014 - 23:39:44 EST


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@xxxxxxxxx>
---
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

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