Merge remote-tracking branch 'linus/master' into testing

1 files changed, 8 insertions, 29 deletions

diff --git a/arch/arm64/mm/flush.c b/arch/arm64/mm/flush.c
index 88611c3a421..e4193e3adc7 100644
--- a/arch/arm64/mm/flush.c
+++ b/arch/arm64/mm/flush.c
@@ -70,23 +70,16 @@ void copy_to_user_page(struct vm_area_struct *vma, struct page *page,
 #endif
 }
 
-void __flush_dcache_page(struct page *page)
-{
-	__flush_dcache_area(page_address(page), PAGE_SIZE);
-}
-
 void __sync_icache_dcache(pte_t pte, unsigned long addr)
 {
-	unsigned long pfn;
-	struct page *page;
+	struct page *page = pte_page(pte);
 
-	pfn = pte_pfn(pte);
-	if (!pfn_valid(pfn))
+	/* no flushing needed for anonymous pages */
+	if (!page_mapping(page))
 		return;
 
-	page = pfn_to_page(pfn);
 	if (!test_and_set_bit(PG_dcache_clean, &page->flags)) {
-		__flush_dcache_page(page);
+		__flush_dcache_area(page_address(page), PAGE_SIZE);
 		__flush_icache_all();
 	} else if (icache_is_aivivt()) {
 		__flush_icache_all();
@@ -94,28 +87,14 @@ void __sync_icache_dcache(pte_t pte, unsigned long addr)
 }
 
 /*
- * Ensure cache coherency between kernel mapping and userspace mapping of this
- * page.
+ * This function is called when a page has been modified by the kernel. Mark
+ * it as dirty for later flushing when mapped in user space (if executable,
+ * see __sync_icache_dcache).
  */
 void flush_dcache_page(struct page *page)
 {
-	struct address_space *mapping;
-
-	/*
-	 * The zero page is never written to, so never has any dirty cache
-	 * lines, and therefore never needs to be flushed.
-	 */
-	if (page == ZERO_PAGE(0))
-		return;
-
-	mapping = page_mapping(page);
-	if (mapping && mapping_mapped(mapping)) {
-		__flush_dcache_page(page);
-		__flush_icache_all();
-		set_bit(PG_dcache_clean, &page->flags);
-	} else {
+	if (test_bit(PG_dcache_clean, &page->flags))
 		clear_bit(PG_dcache_clean, &page->flags);
-	}
 }
 EXPORT_SYMBOL(flush_dcache_page);