Re: [PATCH stable v5.10 0/7] arm64: Default to 32-bit wide ZONE_DMA

[Kefeng Wang]

On 2021/6/23 15:34, Greg KH wrote:
> On Wed, Jun 23, 2021 at 03:25:10PM +0800, Kefeng Wang wrote:
> > On 2021/6/23 15:12, Greg KH wrote:
> > > On Wed, Jun 23, 2021 at 02:59:59PM +0800, Kefeng Wang wrote:
> > > > Hi Greg,
> > > >
> > > > There are two more patches about the ZONE_DMA[32] changes,
> > >
> > > What ZONE_DMA changes?
> >
> > See the subject, [PATCH stable v5.10 0/7] arm64: Default to 32-bit wide
> > ZONE_DMA, We asked the ARM64 ZONE_DMA change backport before, link[1]

Let's inline the link:
https://lore.kernel.org/lkml/20210303073319.2215839-1-jingxiangfeng@xxxxxxxxxx/

The following 7 patches(we asked from link) has merged into lts5.10(tag: 
v5.10.22)

  4d7ed9a49b0c mm: Remove examples from enum zone_type comment
  8eaef922e938 arm64: mm: Set ZONE_DMA size based on early IORT scan
  35ec3d09ff6a arm64: mm: Set ZONE_DMA size based on devicetree's 
dma-ranges
  a9861e7fa4f8 of: unittest: Add test for of_dma_get_max_cpu_address()
  18bf6e998d08 of/address: Introduce of_dma_get_max_cpu_address()
  3fbe62ffbb54 arm64: mm: Move zone_dma_bits initialization into 
zone_sizes_init()
  407b173adfac arm64: mm: Move reserve_crashkernel() into mem_init()

but the patch "arm64: mm: Move reserve_crashkernel() into mem_init()"
has some issue, see the following discussion from Catalin,

https://lore.kernel.org/linux-devicetree/e60d643e-4879-3fc3-737d-2c145332a6d7@xxxxxxx/
https://lore.kernel.org/linux-arm-kernel/20201119175556.18681-1-catalin.marinas@xxxxxxx/

and yes, we met crash in lts5.10 when kexec boot due to "arm64: mm: Move 
reserve_crashkernel() into mem_init()" too, which could be fixed by
commit 2687275a5843 "arm64: Force NO_BLOCK_MAPPINGS if crashkernel 
reservation is required", and the commit 791ab8b2e3db "arm64: Ignore any 
DMA offsets in the max_zone_phys() calculation" also about DMA set,
So I only asked the two patches(both in v5.11) related ARM64 ZONE_DMA 
changes backported into lts5.10.

> The subject doesn't help much, sorry, what commit does this refer to?
> What happened to it?  Was it accepted or rejected?
>
> > > > especially the
> > > > second one, both them need be backported, thanks.
> > >
> > > Backported to where?
> >
> > stable 5.10
>
> Why?

> > > > 791ab8b2e3db - arm64: Ignore any DMA offsets in the max_zone_phys()
> > > > calculation
> > > > 2687275a5843 - arm64: Force NO_BLOCK_MAPPINGS if crashkernel reservation is
> > > > required
> > >
> > > Have you tried these patches?  Where do they need to be applied to?
> >
> > Yes, we tested it, without them, especially the second one, we will
> > meet crash when using kexec boot, also there is discussion in [2]
> > and [3] from Catalin.
>
> These [] do not seem to be links :(
I could see the links is in the end, see 
https://lore.kernel.org/lkml/e47df0fd-0ddd-408b-2972-1b6d0a786f00@xxxxxxxxxx/

> thanks,
>
> greg k-h
> .