[PATCH v13 053/137] mm: Add flush_dcache_folio()

Matthew Wilcox (Oracle)
2021-07-12T03:36:41Z

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 ++++++
arch/nds32/include/asm/cacheflush.h | 1 +
include/asm-generic/cacheflush.h | 6 ++++++
mm/util.c | 13 +++++++++++++
4 files changed, 26 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/arch/nds32/include/asm/cacheflush.h b/arch/nds32/include/asm/cacheflush.h
index 7d6824f7c0e8..f10d13af4ae5 100644
--- a/arch/nds32/include/asm/cacheflush.h
+++ b/arch/nds32/include/asm/cacheflush.h
@@ -38,6 +38,7 @@ void flush_anon_page(struct vm_area_struct *vma,

#define ARCH_HAS_FLUSH_KERNEL_DCACHE_PAGE
void flush_kernel_dcache_page(struct page *page);
+void flush_dcache_folio(struct folio *folio);
void flush_kernel_vmap_range(void *addr, int size);
void invalidate_kernel_vmap_range(void *addr, int size);
#define flush_dcache_mmap_lock(mapping) xa_lock_irq(&(mapping)->i_pages)
diff --git a/include/asm-generic/cacheflush.h b/include/asm-generic/cacheflush.h
index 4a674db4e1fa..fedc0dfa4877 100644
--- a/include/asm-generic/cacheflush.h
+++ b/include/asm-generic/cacheflush.h
@@ -49,9 +49,15 @@ 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
+void flush_dcache_folio(struct folio *folio);
+#endif

#ifndef flush_dcache_mmap_lock
static inline void flush_dcache_mmap_lock(struct address_space *mapping)
diff --git a/mm/util.c b/mm/util.c
index 48d843165a1a..752f611b6220 100644
--- a/mm/util.c
+++ b/mm/util.c
@@ -1047,3 +1047,16 @@ void page_offline_end(void)
up_write(&page_offline_rwsem);
}
EXPORT_SYMBOL(page_offline_end);
+
+#ifndef ARCH_IMPLEMENTS_FLUSH_DCACHE_FOLIO
+void flush_dcache_folio(struct folio *folio)
+{
+ unsigned int n = folio_nr_pages(folio);
+
+ do {
+ n--;
+ flush_dcache_page(folio_page(folio, n));
+ } while (n);
+}
+EXPORT_SYMBOL(flush_dcache_folio);
+#endif
--
2.30.2