2023-01-26 20:07:44

by Matthew Wilcox

Subject: [PATCH] highmem: Round down the address passed to kunmap_flush_on_unmap()

We already round down the address in kunmap_local_indexed() which is
the other implementation of __kunmap_local(). The only implementation
of kunmap_flush_on_unmap() is PA-RISC which is expecting a page-aligned
address. This may be causing PA-RISC to be flushing the wrong addresses
currently.

Signed-off-by: Matthew Wilcox (Oracle) <[email protected]>
Fixes: 298fa1ad5571 ("highmem: Provide generic variant of kmap_atomic*")
Cc: [email protected]
---
include/linux/highmem-internal.h | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/include/linux/highmem-internal.h b/include/linux/highmem-internal.h
index 034b1106d022..e098f38422af 100644
--- a/include/linux/highmem-internal.h
+++ b/include/linux/highmem-internal.h
@@ -200,7 +200,7 @@ static inline void *kmap_local_pfn(unsigned long pfn)
static inline void __kunmap_local(const void *addr)
{
#ifdef ARCH_HAS_FLUSH_ON_KUNMAP
- kunmap_flush_on_unmap(addr);
+ kunmap_flush_on_unmap(PTR_ALIGN_DOWN(addr, PAGE_SIZE));
#endif
}

@@ -227,7 +227,7 @@ static inline void *kmap_atomic_pfn(unsigned long pfn)
static inline void __kunmap_atomic(const void *addr)
{
#ifdef ARCH_HAS_FLUSH_ON_KUNMAP
- kunmap_flush_on_unmap(addr);
+ kunmap_flush_on_unmap(PTR_ALIGN_DOWN(addr, PAGE_SIZE));
#endif
pagefault_enable();
if (IS_ENABLED(CONFIG_PREEMPT_RT))
--
2.35.1

2023-01-27 22:54:07

by Ira Weiny

Subject: Re: [PATCH] highmem: Round down the address passed to kunmap_flush_on_unmap()

Matthew Wilcox (Oracle) wrote:
> We already round down the address in kunmap_local_indexed() which is
> the other implementation of __kunmap_local(). The only implementation
> of kunmap_flush_on_unmap() is PA-RISC which is expecting a page-aligned
> address. This may be causing PA-RISC to be flushing the wrong addresses
> currently.
>
> Signed-off-by: Matthew Wilcox (Oracle) <[email protected]>

Reviewed-by: Ira Weiny <[email protected]>

> Fixes: 298fa1ad5571 ("highmem: Provide generic variant of kmap_atomic*")
> Cc: [email protected]
> ---
> include/linux/highmem-internal.h | 4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/include/linux/highmem-internal.h b/include/linux/highmem-internal.h
> index 034b1106d022..e098f38422af 100644
> --- a/include/linux/highmem-internal.h
> +++ b/include/linux/highmem-internal.h
> @@ -200,7 +200,7 @@ static inline void *kmap_local_pfn(unsigned long pfn)
> static inline void __kunmap_local(const void *addr)
> {
> #ifdef ARCH_HAS_FLUSH_ON_KUNMAP
> - kunmap_flush_on_unmap(addr);
> + kunmap_flush_on_unmap(PTR_ALIGN_DOWN(addr, PAGE_SIZE));
> #endif
> }
>
> @@ -227,7 +227,7 @@ static inline void *kmap_atomic_pfn(unsigned long pfn)
> static inline void __kunmap_atomic(const void *addr)
> {
> #ifdef ARCH_HAS_FLUSH_ON_KUNMAP
> - kunmap_flush_on_unmap(addr);
> + kunmap_flush_on_unmap(PTR_ALIGN_DOWN(addr, PAGE_SIZE));
> #endif
> pagefault_enable();
> if (IS_ENABLED(CONFIG_PREEMPT_RT))
> --
> 2.35.1
>