On Thu, Aug 28, 2025 at 10:51:46PM +0200, David Hildenbrand wrote:

On 28.08.25 18:57, Lorenzo Stoakes wrote:

quoted

On Thu, Aug 28, 2025 at 12:01:24AM +0200, David Hildenbrand wrote:

quoted

Let's make it clearer that we are operating within a single folio by
providing both the folio and the page.

This implies that for flush_dcache_folio() we'll now avoid one more
page->folio lookup, and that we can safely drop the "nth_page" usage.

Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Signed-off-by: David Hildenbrand <redacted>
---
  arch/mips/include/asm/cacheflush.h | 11 +++++++----
  arch/mips/mm/cache.c               |  8 ++++----
  2 files changed, 11 insertions(+), 8 deletions(-)

diff --git a/arch/mips/include/asm/cacheflush.h b/arch/mips/include/asm/cacheflush.h
index 5d283ef89d90d..8d79bfc687d21 100644
--- a/arch/mips/include/asm/cacheflush.h
+++ b/arch/mips/include/asm/cacheflush.h

@@ -50,13 +50,14 @@ extern void (*flush_cache_mm)(struct mm_struct *mm);
  extern void (*flush_cache_range)(struct vm_area_struct *vma,
  	unsigned long start, unsigned long end);
  extern void (*flush_cache_page)(struct vm_area_struct *vma, unsigned long page, unsigned long pfn);
-extern void __flush_dcache_pages(struct page *page, unsigned int nr);
+extern void __flush_dcache_folio_pages(struct folio *folio, struct page *page, unsigned int nr);

NIT: Be good to drop the extern.

I think I'll leave the one in, though, someone should clean up all of them
in one go.

This is how we always clean these up though, buuut to be fair that's in mm.

Just imagine how the other functions would think about the new guy showing
off here. :)

;)

quoted

quoted

  #define ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE 1
  static inline void flush_dcache_folio(struct folio *folio)
  {
  	if (cpu_has_dc_aliases)
-		__flush_dcache_pages(&folio->page, folio_nr_pages(folio));
+		__flush_dcache_folio_pages(folio, folio_page(folio, 0),
+					   folio_nr_pages(folio));
  	else if (!cpu_has_ic_fills_f_dc)
  		folio_set_dcache_dirty(folio);
  }

@@ -64,10 +65,12 @@ static inline void flush_dcache_folio(struct folio *folio)

  static inline void flush_dcache_page(struct page *page)
  {
+	struct folio *folio = page_folio(page);
+
  	if (cpu_has_dc_aliases)
-		__flush_dcache_pages(page, 1);
+		__flush_dcache_folio_pages(folio, page, folio_nr_pages(folio));

Hmmm, shouldn't this be 1 not folio_nr_pages()? Seems that the original
implementation only flushed a single page even if contained within a larger
folio?

Yes, reworked it 3 times and messed it up during the last rework. Thanks!

Woot I found an actual bug :P

Yeah it's fiddly so understandable. :)

--
Cheers

David / dhildenb

Cheers, Lorenzo