Re: [PATCH 4/5] arch/kmap_atomic: Consolidate duplicate code
On Sun, Apr 26, 2020 at 12:26:42AM -0700, Christoph Hellwig wrote:
> > diff --git a/arch/arc/mm/highmem.c b/arch/arc/mm/highmem.c
> > index 4db13a6b9f3b..1cae4b911a33 100644
> > --- a/arch/arc/mm/highmem.c
> > +++ b/arch/arc/mm/highmem.c
> > @@ -53,11 +53,10 @@ void *kmap_atomic(struct page *page)
> > {
> > int idx, cpu_idx;
> > unsigned long vaddr;
> > + void *addr = kmap_atomic_fast(page);
> >
> > - preempt_disable();
> > - pagefault_disable();
> > - if (!PageHighMem(page))
> > - return page_address(page);
> > + if (addr)
> > + return addr;
>
> Wouldn't it make sense to just move kmap_atomic itelf to common code,
> and call out to a kmap_atomic_high for the highmem case, following the
> scheme in kmap?
>
Sure I do like that symmetry between the calls.
>
> Same for the unmap side.
FWIW that would simply be renaming __kunmap_atomic() to kunmap_atomic_high()
>
> That might require to support
> kmap_atomic_prot everywhere first, which sounds like a really good
> idea anyway, and would avoid the need for strange workaround in drm.
Having a kmap_atomic_prot() seems like a good idea. But I'm not exactly sure
why CONFIG_x86 is being called out specifically in the DRM code?
Ira
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Re: [PATCH 2/5] arch/kmap: Remove redundant arch specific kmaps
On Sun, Apr 26, 2020 at 12:17:15AM -0700, Christoph Hellwig wrote: > On Sat, Apr 25, 2020 at 10:54:03PM -0700, ira.we...@intel.com wrote: > > From: Ira Weiny > > > > The kmap code for all the architectures is almost 100% identical. > > > > Lift the common code to the core. Use ARCH_HAS_KMAP to indicate if an > > arch needs a special kmap. > > Can you add a kmap_flush_tlb hook that csky and mips define, and the > just entirely consolidate the code instead? Sure that seems to work. Ira ___ linux-snps-arc mailing list linux-snps-arc@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-snps-arc
Re: [PATCH 4/5] arch/kmap_atomic: Consolidate duplicate code
> diff --git a/arch/arc/mm/highmem.c b/arch/arc/mm/highmem.c
> index 4db13a6b9f3b..1cae4b911a33 100644
> --- a/arch/arc/mm/highmem.c
> +++ b/arch/arc/mm/highmem.c
> @@ -53,11 +53,10 @@ void *kmap_atomic(struct page *page)
> {
> int idx, cpu_idx;
> unsigned long vaddr;
> + void *addr = kmap_atomic_fast(page);
>
> - preempt_disable();
> - pagefault_disable();
> - if (!PageHighMem(page))
> - return page_address(page);
> + if (addr)
> + return addr;
Wouldn't it make sense to just move kmap_atomic itelf to common code,
and call out to a kmap_atomic_high for the highmem case, following the
scheme in kmap? Same for the unmap side. That might require to support
kmap_atomic_prot everywhere first, which sounds like a really good
idea anyway, and would avoid the need for strange workaround in drm.
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Re: [PATCH 2/5] arch/kmap: Remove redundant arch specific kmaps
On Sat, Apr 25, 2020 at 10:54:03PM -0700, ira.we...@intel.com wrote: > From: Ira Weiny > > The kmap code for all the architectures is almost 100% identical. > > Lift the common code to the core. Use ARCH_HAS_KMAP to indicate if an > arch needs a special kmap. Can you add a kmap_flush_tlb hook that csky and mips define, and the just entirely consolidate the code instead? ___ linux-snps-arc mailing list linux-snps-arc@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-snps-arc
