Re: mainline build failure due to b67fbebd4cf9 ("mmu_gather: Force tlb-flush VM_PFNMAP vmas")

[Linus Torvalds <torvalds@linux-foundation.org>]

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On Fri, Jul 22, 2022 at 12:53 AM Sudip Mukherjee (Codethink)
<sudipm.mukherjee@gmail.com> wrote:
>
> The latest mainline kernel branch fails to build for alpha allmodconfig
> with the error:

Gaah. It's the odd MMU_GATHER_NO_RANGE architectures - alpha, m68k,
microblaze, nios2 and openrisc.

We should probably get rid of that oddity, and force everybody to have
the ranged tlb flush functions, but for now the trivial patch is to
just remove the left-over dummy tlb_update_vma_flags() from that case,
I think.

Trivial patch attached. I don't have any cross-compiler for those
architectures on my machine, but I suspect I'll just commit it as-is
even without testing, since it can't be worse than what the situation
is right now with that "redefinition of 'tlb_update_vma_flags'"

But if you can verify, that would be lovely.

                    Linus

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 include/asm-generic/tlb.h | 3 ---
 1 file changed, 3 deletions(-)

diff --git a/include/asm-generic/tlb.h b/include/asm-generic/tlb.h
index cb2167c89eee..492dce43236e 100644
--- a/include/asm-generic/tlb.h
+++ b/include/asm-generic/tlb.h
@@ -368,9 +368,6 @@ static inline void tlb_flush(struct mmu_gather *tlb)
 		flush_tlb_mm(tlb->mm);
 }
 
-static inline void
-tlb_update_vma_flags(struct mmu_gather *tlb, struct vm_area_struct *vma) { }
-
 #else /* CONFIG_MMU_GATHER_NO_RANGE */
 
 #ifndef tlb_flush