2021-03-11 15:06:04

by Lv Yunlong

Subject: [PATCH] usb/usbtmc: Remove a redundant kref_put in usbtmc_disconnect

In the implementation of usbtmc_free_int(), it already calls
kref_put() to free the data as shown below. So, in
usbtmc_disconnect, call an extra kref_put() is redundant.

"""
static void usbtmc_free_int(struct usbtmc_device_data *data)
{
if (!data->iin_ep_present || !data->iin_urb)
return;
usb_kill_urb(data->iin_urb);
kfree(data->iin_buffer);
data->iin_buffer = NULL;
usb_free_urb(data->iin_urb);
data->iin_urb = NULL;
kref_put(&data->kref, usbtmc_delete);
}
"""

Signed-off-by: Lv Yunlong <[email protected]>
---
drivers/usb/class/usbtmc.c | 1 -
1 file changed, 1 deletion(-)

diff --git a/drivers/usb/class/usbtmc.c b/drivers/usb/class/usbtmc.c
index 74d5a9c5238a..adcdd2df1949 100644
--- a/drivers/usb/class/usbtmc.c
+++ b/drivers/usb/class/usbtmc.c
@@ -2494,7 +2494,6 @@ static void usbtmc_disconnect(struct usb_interface *intf)
}
mutex_unlock(&data->io_mutex);
usbtmc_free_int(data);
- kref_put(&data->kref, usbtmc_delete);
}

static void usbtmc_draw_down(struct usbtmc_file_data *file_data)
--
2.25.1

2021-03-12 14:34:31

by Greg Kroah-Hartman

Subject: Re: [PATCH] usb/usbtmc: Remove a redundant kref_put in usbtmc_disconnect

On Thu, Mar 11, 2021 at 07:03:54AM -0800, Lv Yunlong wrote:
> In the implementation of usbtmc_free_int(), it already calls
> kref_put() to free the data as shown below. So, in
> usbtmc_disconnect, call an extra kref_put() is redundant.
>
> """
> static void usbtmc_free_int(struct usbtmc_device_data *data)
> {
> if (!data->iin_ep_present || !data->iin_urb)
> return;
> usb_kill_urb(data->iin_urb);
> kfree(data->iin_buffer);
> data->iin_buffer = NULL;
> usb_free_urb(data->iin_urb);
> data->iin_urb = NULL;
> kref_put(&data->kref, usbtmc_delete);
> }
> """
>
> Signed-off-by: Lv Yunlong <[email protected]>
> ---
> drivers/usb/class/usbtmc.c | 1 -
> 1 file changed, 1 deletion(-)
>
> diff --git a/drivers/usb/class/usbtmc.c b/drivers/usb/class/usbtmc.c
> index 74d5a9c5238a..adcdd2df1949 100644
> --- a/drivers/usb/class/usbtmc.c
> +++ b/drivers/usb/class/usbtmc.c
> @@ -2494,7 +2494,6 @@ static void usbtmc_disconnect(struct usb_interface *intf)
> }
> mutex_unlock(&data->io_mutex);
> usbtmc_free_int(data);
> - kref_put(&data->kref, usbtmc_delete);

Did you test this change?

If not, please do so, I think the code is fine as-is.

thanks,

greg k-h