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

[Wandun <chenwandun1@gmail.com>]

On 10/22/26 17:59, Marek Szyprowski wrote:
> 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/

Hi Marek, Rob,

Since this restructuring and my series touch the same code paths, my
plan is to rebase my series on top of this series once it lands, and
send a v4 then. Is that OK?


Best regards,
Wandun

> 
> 
>> 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