Re: [PATCH 3/4] bas_gigaset: suspend support (v2)

Re: [PATCH 3/4] bas_gigaset: suspend support (v2)

[Andrew Morton]

On Tue, 13 Nov 2007 18:30:30 +0100 (CET)
Tilman Schmidt <tilman@imap.cc> wrote:

> From: Tilman Schmidt <tilman@imap.cc>
> 
> This patch adds basic suspend/resume support to the bas_gigaset ISDN
> driver for the Siemens Gigaset SX255 series of ISDN DECT bases.
> 
> Only the USB aspects are handled so far; the ISDN subsystem is not
> notified  in any way, for lack of information about how to do that.
> The driver will refuse to suspend if a connection is active.
> 
> ...
>
> +	if (atomic_read(&cs->hw.bas->basstate) & BS_SUSPEND) {

that's pretty peculiar.  We'd only expect to see atomics being used in
conjunction with atomic_add/sub/inc/etc.  Here the driver is using an
atomic_t as a state variable.  And here's the magic bit:

	spin_lock_irqsave(&ucs->lock, flags);
	state = atomic_read(&ucs->basstate);
	atomic_set(&ucs->basstate, (state & ~clear) | set);
	spin_unlock_irqrestore(&ucs->lock, flags);

I'm suspecting that a plain old `int' would be more appropriate here.

Re: [PATCH 3/4] bas_gigaset: suspend support (v2)

[Tilman Schmidt]

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Am 15.11.2007 23:50 schrieb Andrew Morton:
>> ...
>>
>> +	if (atomic_read(&cs->hw.bas->basstate) & BS_SUSPEND) {
> 
> that's pretty peculiar.  We'd only expect to see atomics being used in
> conjunction with atomic_add/sub/inc/etc.  Here the driver is using an
> atomic_t as a state variable.  And here's the magic bit:
> 
> 	spin_lock_irqsave(&ucs->lock, flags);
> 	state = atomic_read(&ucs->basstate);
> 	atomic_set(&ucs->basstate, (state & ~clear) | set);
> 	spin_unlock_irqrestore(&ucs->lock, flags);
> 
> I'm suspecting that a plain old `int' would be more appropriate here.

You're right. That's a prehistoric leftover. That variable was
originally accessed using atomic_set_mask() and atomic_clear_mask()
which are unfortunately x86 platform specific.

I'll prepare a cleanup patch.

Thanks,
Tilman

-- 
Tilman Schmidt                          E-Mail: tilman@imap.cc
Bonn, Germany
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