2012-10-10 10:33:04

by Constantine Shulyupin

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

From: Constantine Shulyupin <[email protected]>

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 [email protected]: also need to drop the lock.

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

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;
--
1.7.9.5

2012-10-10 12:37:24

by Oliver Neukum

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

On Wednesday 10 October 2012 12:32:54 Constantine Shulyupin wrote:
> From: Constantine Shulyupin <[email protected]>
>
> 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 [email protected]: 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