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From: Heiko Stuebner <heiko@sntech.de>
To: Andrew Morton <akpm@linux-foundation.org>,
        Matthew Wilcox <willy@infradead.org>,
        Matthew Wilcox <mawilcox@microsoft.com>,
        Zhang Rui <rui.zhang@intel.com>,
        Eduardo Valentin <edubezval@gmail.com>
Cc: linux-kernel@vger.kernel.org
Subject: thermal zones break with patch "Reimplement IDR and IDA using the radix tree" (mainline+next)
Date: Fri, 16 Dec 2016 22:12:53 +0100
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Hi,

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:

[    9.397201] WARNING: CPU: 1 PID: 165 at ../fs/sysfs/dir.c:31 sysfs_warn_dup+0x64/0x74
[    9.405145] sysfs: cannot create duplicate filename '/devices/virtual/thermal/thermal_zone1'
[    9.514951] Hardware name: Rockchip (Device Tree)
[    9.522611] [<c03104a4>] (unwind_backtrace) from [<c030ba50>] (show_stack+0x10/0x14)
[    9.532925] [<c030ba50>] (show_stack) from [<c05a11fc>] (dump_stack+0x88/0x9c)
[    9.542695] [<c05a11fc>] (dump_stack) from [<c0340c68>] (__warn+0xe8/0x100)
[    9.552166] [<c0340c68>] (__warn) from [<c0340cb8>] (warn_slowpath_fmt+0x38/0x48)
[    9.562154] [<c0340cb8>] (warn_slowpath_fmt) from [<c047e944>] (sysfs_warn_dup+0x64/0x74)
[    9.572834] [<c047e944>] (sysfs_warn_dup) from [<c047ea20>] (sysfs_create_dir_ns+0x84/0x94)
[    9.583687] [<c047ea20>] (sysfs_create_dir_ns) from [<c05a2cb8>] (kobject_add_internal+0xac/0x2fc)
[    9.595149] [<c05a2cb8>] (kobject_add_internal) from [<c05a2f50>] (kobject_add+0x48/0x98)
[    9.605829] [<c05a2f50>] (kobject_add) from [<c07ee340>] (device_add+0xd4/0x5b0)
[    9.615714] [<c07ee340>] (device_add) from [<c0a43a98>] (thermal_zone_device_register+0x174/0x5cc)
[    9.627173] [<c0a43a98>] (thermal_zone_device_register) from [<c0a3c588>] (__power_supply_register+0x374/0x44c)
[    9.639772] [<c0a3c588>] (__power_supply_register) from [<c0a3c6bc>] (devm_power_supply_register+0x4c/0x7c)

System is a Rockchip rk3288-veyron and it has 4 thermal zones (3 from
the thermal ip block of the soc and one from the battery).

Reverting the patch mentioned above results in thermal zones being
registered again.

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


Heiko