Re: Empty critical section issue in Bluetooth Linux driver code

[Dan Carpenter <error27@gmail.com>]

On Tue, Jul 13, 2010 at 12:50:40PM +0200, "Tegawendé F. Bissyandé" wrote:
> Hi,
>
> I have been using Coccinelle to validate some trivial rules of kernel
> API use by device drivers.
> I came accross the definition of an empty critical section in the
> 'bfusb_close' function in file drivers/bluetooth/bfusb.c
>
> static int bfusb_close(struct hci_dev *hdev)
> {
>     ...
>     write_lock_irqsave(&data->lock, flags);
>     write_unlock_irqrestore(&data->lock, flags);
>

This is in the _close() function.  It's waiting for all the readers to
finish.  Presumably it's already ensured that no new reader threads will
launch.

regards,
dan carpenter

>     bfusb_unlink_urbs(data);
>     bfusb_flush(hdev);
>
>     return 0;
> }


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