[v2] USB: usb-skeleton.c: fix compilation error and restore kref_put on fail in skel_open

Commit Message

Constantine Shulyupin Oct. 10, 2012, 10:32 a.m. UTC

From: Constantine Shulyupin <[e-mail]>

Function skel_open increments usage count for the device with kref_get and the usage count should be decremented on the function failure.

Some last changes in function skel_open and finally commit
52a7499 Revert "USB: usb-skeleton.c: fix open/disconnect race"
introduced a bug in function skel_open, which this patch fixes.

--
Changelog:
-- Fixed accordinly feedback of Oliver Neukum [e-mail]: also need to drop the lock.

Signed-off-by: Constantine Shulyupin <[e-mail]>
---
 drivers/usb/usb-skeleton.c |    5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

Comments

Oliver Neukum Oct. 10, 2012, 12:35 p.m. UTC | #1

On Wednesday 10 October 2012 12:32:54 Constantine Shulyupin wrote:
> From: Constantine Shulyupin <[e-mail]>
> 
> Function skel_open increments usage count for the device with kref_get and the usage count should be decremented on the function failure.
> 
> Some last changes in function skel_open and finally commit
> 52a7499 Revert "USB: usb-skeleton.c: fix open/disconnect race"
> introduced a bug in function skel_open, which this patch fixes.
> 
> --
> Changelog:
> -- Fixed accordinly feedback of Oliver Neukum [e-mail]: also need to drop the lock.

Well, touching file->private_data is not nice. It is correct, but
really dirty. The skeleton driver should be nice. Could you introduce
a second label for goto at the right place?

	Regards
		Oliver

Patch

diff --git a/drivers/usb/usb-skeleton.c b/drivers/usb/usb-skeleton.c
index 0616f23..2025d03 100644
--- a/drivers/usb/usb-skeleton.c
+++ b/drivers/usb/usb-skeleton.c
@@ -113,8 +113,9 @@  static int skel_open(struct inode *inode, struct file *file)
 	mutex_lock(&dev->io_mutex);
 
 	retval = usb_autopm_get_interface(interface);
-	if (retval)
-		goto out_err;
+	if (retval) {
+		kref_put(&dev->kref, skel_delete);
+	}
 
 	/* save our object in the file's private structure */
 	file->private_data = dev;