[PATCH v9 46/96] mm: Add flush_dcache_folio
From: "Matthew Wilcox (Oracle)" <willy@infradead.org>
Date: 2021-05-05 16:05:21
Also in:
linux-fsdevel, lkml
Subsystem:
documentation, generic include/asm header files, the rest · Maintainers:
Jonathan Corbet, Arnd Bergmann, Linus Torvalds
This is a default implementation which calls flush_dcache_page() on each page in the folio. If architectures can do better, they should implement their own version of it. Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org> --- Documentation/core-api/cachetlb.rst | 6 ++++++ include/asm-generic/cacheflush.h | 14 ++++++++++++++ 2 files changed, 20 insertions(+)
diff --git a/Documentation/core-api/cachetlb.rst b/Documentation/core-api/cachetlb.rst
index fe4290e26729..29682f69a915 100644
--- a/Documentation/core-api/cachetlb.rst
+++ b/Documentation/core-api/cachetlb.rst@@ -325,6 +325,12 @@ maps this page at its virtual address. dirty. Again, see sparc64 for examples of how to deal with this. + ``void flush_dcache_folio(struct folio *folio)`` + This function is called under the same circumstances as + flush_dcache_page(). It allows the architecture to + optimise for flushing the entire folio of pages instead + of flushing one page at a time. + ``void copy_to_user_page(struct vm_area_struct *vma, struct page *page, unsigned long user_vaddr, void *dst, void *src, int len)`` ``void copy_from_user_page(struct vm_area_struct *vma, struct page *page,
diff --git a/include/asm-generic/cacheflush.h b/include/asm-generic/cacheflush.h
index 4a674db4e1fa..0155357b840f 100644
--- a/include/asm-generic/cacheflush.h
+++ b/include/asm-generic/cacheflush.h@@ -49,9 +49,23 @@ static inline void flush_cache_page(struct vm_area_struct *vma, static inline void flush_dcache_page(struct page *page) { } + +static inline void flush_dcache_folio(struct folio *folio) { } #define ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE 0 +#define ARCH_IMPLEMENTS_FLUSH_DCACHE_FOLIO #endif +#ifndef ARCH_IMPLEMENTS_FLUSH_DCACHE_FOLIO +static inline void flush_dcache_folio(struct folio *folio) +{ + unsigned int n = folio_nr_pages(folio); + + do { + n--; + flush_dcache_page(nth_page(&folio->page, n)); + } while (n); +} +#endif #ifndef flush_dcache_mmap_lock static inline void flush_dcache_mmap_lock(struct address_space *mapping)
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2.30.2