Re: [RFC PATCH 2/2] mm: mmu_notifier fix for tlb_end_vma (build failures)

[Will Deacon]

On Fri, Aug 24, 2018 at 06:24:19AM -0700, Guenter Roeck wrote:
> On Fri, Aug 24, 2018 at 02:10:27PM +0100, Will Deacon wrote:
> > On Fri, Aug 24, 2018 at 06:07:22AM -0700, Guenter Roeck wrote:
> > > On Thu, Aug 23, 2018 at 06:47:09PM +1000, Nicholas Piggin wrote:
> > > > The generic tlb_end_vma does not call invalidate_range mmu notifier,
> > > > and it resets resets the mmu_gather range, which means the notifier
> > > > won't be called on part of the range in case of an unmap that spans
> > > > multiple vmas.
> > > > 
> > > > ARM64 seems to be the only arch I could see that has notifiers and
> > > > uses the generic tlb_end_vma. I have not actually tested it.
> > > > 
> > > > Signed-off-by: Nicholas Piggin <npiggin@xxxxxxxxx>
> > > > Acked-by: Will Deacon <will.deacon@xxxxxxx>
> > > 
> > > This patch breaks riscv builds in mainline.
> > 
> > Looks very similar to the breakage we hit on arm64. diff below should fix
> > it.
> > 
> 
> Unfortunately it doesn't.
> 
> In file included from ./arch/riscv/include/asm/pgtable.h:26:0,
>                  from ./include/linux/memremap.h:7,
>                  from ./include/linux/mm.h:27,
>                  from arch/riscv/mm/fault.c:23:
> ./arch/riscv/include/asm/tlb.h: In function âtlb_flushâ:
> ./arch/riscv/include/asm/tlb.h:19:18: error: dereferencing pointer to incomplete type âstruct mmu_gatherâ
>   flush_tlb_mm(tlb->mm);
>                   ^

Sorry, I was a bit quick of the mark there. You'll need a forward
declaration for the paramater type. Here it is with a commit message,
although still untested because I haven't got round to setting up a riscv
toolchain yet.

Will

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