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@xxxxxxxxxxxxx>
---
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)
--
2.30.2
