Re: thermal zones break with patch "Reimplement IDR and IDA using the radix tree" (mainline+next)

From: Andy Shevchenko
Date: Sun Dec 18 2016 - 14:43:32 EST


On Fri, Dec 16, 2016 at 11:19 PM, Matthew Wilcox <mawilcox@xxxxxxxxxxxxx> wrote:
> From: Heiko Stuebner [mailto:heiko@xxxxxxxxx]
>> commit b05bbe3ea2db ("Reimplement IDR and IDA using the radix tree")
>> seems to
>> break thermal zone allocation. This happens both on todays mainline and
>> linux-next-20161216 and produces errors like:
>
>> While I haven't looked to deeply into what idr exactly does, some findings:
>> - thermal_zone0 and thermal_zone1 are allocated correctly
>> - every further thermal_zone always gets allocated the number "1"
>> - thermal core calls idr_alloc with 0 for both start and end
>> - the rewrite-patch seems to change the semantics of idr_alloc
>> where it orignally said "@end: the maximum id (exclusive, <= 0 for max)"
>> the "<= 0" part is gone now, but I checked, simply setting INT_MAX
>> as end in the thermal_core does not help
>
> Hi Heiko,
>
> Thanks for the report! The problem is because the thermal subsystem calls idr_alloc() passing a NULL pointer for the data. I have fixed this problem in my git tree but haven't sent the patch to Andrew yet. This patch should fix the problem for you:
>
> http://git.infradead.org/users/willy/linux-dax.git/commitdiff/c52eeed7b759c3fefe9b7f1b0a17a438df6950f3
>
> Now ... thermal is actually using an IDR when it could save memory by using an IDA. Are you interested in doing that conversion?

+Cc: Mika, Vinod

Same here for at least DMA Engine (and perhaps another place in
thermal subsystem).

For DMA Engine case

Tested-by: Andy Shevchenko <andy.shevchenko@xxxxxxxxx>

--
With Best Regards,
Andy Shevchenko