Re: Is devm_* broken ?

From: Dmitry Torokhov
Date: Tue Aug 04 2015 - 17:26:36 EST


On Tue, Aug 4, 2015 at 12:56 PM, Pavel Machek <pavel@xxxxxx> wrote:
> On Tue 2015-07-28 20:05:49, Laurent Pinchart wrote:
>> On Tuesday 28 July 2015 11:22:25 Tejun Heo wrote:
>> > On Tue, Jul 28, 2015 at 05:16:16PM +0300, Laurent Pinchart wrote:
>> > > Using devm_kzalloc() in such a way has value though, and reverting drivers
>> > > to the pre-devm memory allocation code would make error handling and
>> > > cleanup code paths more complex again. Should we introduce a managed
>> > > allocator for that purpose that would have a lifespan explicitly handled
>> > > by drivers ?
>> >
>> > I don't know. Sure, we can have memory allocations which are tied to
>> > open file; however, the distinction between that and regular devm
>> > resources, which can't linger on no matter what, would be subtle and
>> > confusing. IMHO, a better approach would be implmenting generic
>> > revoke feature and sever open files on driver detach so that
>> > everything can be shutdown then.
>>
>> Sounds like a topic for the kernel summit :-) I'll send a proposal.
>
> Hmm. But that means that devm_ everything is broken for 6 months or
> so, right?
>
> Does it mean we should stop taking new devm_ conversions at the very
> least?

No, we should continue carefully review them and take the ones that make sense.

Thanks.

--
Dmitry
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