Re: [PATCH v3 0/2] of: reserved_mem: use dynamically allocated reserved_mem array

[Marek Szyprowski <m.szyprowski@samsung.com>]

On 21.10.2026 15:41, Rob Herring wrote:
> On Thu, Oct 15, 2026 at 10:23:10AM +0200, Marek Szyprowski wrote:
>> Mike Rapoport suggested [1] how to properly use dynamically allocated
>> arrays during early boot.
>>
>> Use this approach for reserved_mem array during early scan of the
>> reserved regions. Having all the reserved regions in a single array
>> removes the need of the two pass initialization introduced by commit
>> 8a6e02d0c00e ("of: reserved_mem: Restructure how the reserved memory
>> regions are processed"), so implement it to make the code simpler,
>> easier to understand and ready for adding proper error checking.
>>
>> Tested on ARM32, ARM64 and RiscV64 based boards. Arch specific issues
>> with early mappings were discovered by LLM.
>>
>> [1] https://lore.kernel.org/all/asc6brs_g0ky0wOM@kernel.org/
>>
>>
>> Best regards
>> Marek Szyprowski, PhD
>> Samsung R&D Institute Poland
>>
>>
>> Changelog:
>>
>> v3:
>> - allocate the reserved_mem array only after all static regions are
>>   reserved or marked as no-map, so it cannot be placed inside any of
>>   them
>> - record failures of the early static reservations and print a single
>>   message asking to fix the device-tree
>> - restore conditional compilation of the early mapping code, because
>>   some architectures lack support for it (C-SKY & Sparc64 as reported
>>   by kbuild robot)
>> - allocate the array bottom-up, to avoid allocating from highmem, what
>>   might be an issue on Xtensa, C-SKY and MIPS32
>> - don't use the early mapping on PPC64, where the scan is done before
>>   early_ioremap_setup()
>>
>> v2: https://lore.kernel.org/all/20261008152403.766439-1-m.szyprowski@samsung.com/
>> - removed superfluous ifdefs
>>
>> v1: https://lore.kernel.org/all/20261008094125.3197971-1-m.szyprowski@samsung.com/
>> - initial version
>>
>>
>> Patch summary:
>>
>> Marek Szyprowski (2):
>>   of: reserved_mem: group allocation helpers together
>>   of: reserved_mem: allocate and map the reserved_mem array early
> Can you confirm the sashiko issues are not issues?


I've replied sashiko review. That are again the preexisting issues initially
targeted by Wandun's patchset:

https://lore.kernel.org/all/20260920092852.614973-1-chenwandun1@gmail.com/


> I'll apply this after rc1. Are you willing to be added as reviewer or 
> maintainer for this code? I'd prefer not to have another entry just for 
> the reserved mem code, so you'd have to filter out the rest of the DT 
> code (not the bindings and dts firehose) which isn't too much.

Okay, I can try to take a look at the drivers/of related code as reviewer.
I will filter it out to reserved_mem related changes locally.


Best regards
-- 
Marek Szyprowski, PhD
Samsung R&D Institute Poland