On 5/6/07, Alan Stern <stern@xxxxxxxxxxxxxxxxxxx> wrote:
> On Sun, 6 May 2007, Satyam Sharma wrote:
>
> > Anyway, the hci_notifier is called from the following six call sites:
> >
> > hci_dev_open() and hci_dev_close() -> both called from
> > hci_sock_ioctl() => both can sleep
> > hci_register_dev() and hci_unregister_dev() => again both are capable
> > of sleeping
> > hci_suspend_dev() and hci_resume_dev() -> called from the .suspend()
> > and .resume() of the hci_usb_driver, and again both of these can sleep
> >
> > Is there any other reason why hci_notifier must be an atomic notifier?
> >
> > (CC'ing Alan Stern just in case, apparently hci_notifier became atomic
> > when notifier chains were classified into atomic / blocking)
>
> I don't remember exactly why this particular choice was made. Perhaps we
> found that the notifier callout routines didn't use any blocking
> primitives (we may have been mistaken about this -- there was a lot of
> code to check) and so therefore the choice didn't matter. In that case we
> probably just decided to make it an atomic notifier to keep things simple.
>
> As you found, changing it to a blocking notifier is very easy. Provided
> all the callers are non-atomic it should work just fine.
Okay, I'll go ahead and try the patch, then, and report back.