On Mon, Sep 22, 2014 at 10:39:18PM +0300, Octavian Purdila wrote:
> Currently the I/O buffer is allocated part of the device status
> structure, potentially sharing the same cache line with other members
> in this structure.
> 
> Allocate the buffer separately, to avoid the I/O operations corrupting
> the device status structure due to cache line sharing.
> 
> Compiled tested only as I don't have access to hardware.
> 
> Signed-off-by: Octavian Purdila <octavian.purd...@intel.com>
> ---
>  drivers/mfd/viperboard.c       | 8 ++++++++
>  include/linux/mfd/viperboard.h | 2 +-
>  2 files changed, 9 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/mfd/viperboard.c b/drivers/mfd/viperboard.c
> index e00f534..5f62f4e 100644
> --- a/drivers/mfd/viperboard.c
> +++ b/drivers/mfd/viperboard.c
> @@ -64,6 +64,12 @@ static int vprbrd_probe(struct usb_interface *interface,
>               return -ENOMEM;
>       }
>  
> +     vb->buf = kzalloc(sizeof(struct vprbrd_i2c_write_msg), GFP_KERNEL);
> +     if (vb->buf == NULL) {
> +             ret = -ENOMEM;
> +             goto error;

This will cause a kref imbalance as you have a usb_put_dev in error,
but haven't done the get yet.

> +     }
> +
>       mutex_init(&vb->lock);
>  
>       vb->usb_dev = usb_get_dev(interface_to_usbdev(interface));

Here's the get.

Johan
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