--- zzzz-none-000/linux-3.10.107/include/linux/highmem.h	2017-06-27 09:49:32.000000000 +0000
+++ scorpion-7490-727/linux-3.10.107/include/linux/highmem.h	2021-02-04 17:41:59.000000000 +0000
@@ -39,6 +39,12 @@
 
 void kmap_flush_unused(void);
 
+#ifdef CONFIG_ARCH_WANT_KMAP_ATOMIC_FLUSH
+void kmap_atomic_flush_unused(void);
+#else
+static inline void kmap_atomic_flush_unused(void) { }
+#endif
+
 struct page *kmap_to_page(void *addr);
 
 #else /* CONFIG_HIGHMEM */
@@ -65,6 +71,7 @@
 
 static inline void *kmap_atomic(struct page *page)
 {
+	preempt_disable();
 	pagefault_disable();
 	return page_address(page);
 }
@@ -73,12 +80,13 @@
 static inline void __kunmap_atomic(void *addr)
 {
 	pagefault_enable();
+	preempt_enable();
 }
 
 #define kmap_atomic_pfn(pfn)	kmap_atomic(pfn_to_page(pfn))
-#define kmap_atomic_to_page(ptr)	virt_to_page(ptr)
 
 #define kmap_flush_unused()	do {} while(0)
+#define kmap_atomic_flush_unused()	do {} while (0)
 #endif
 
 #endif /* CONFIG_HIGHMEM */
@@ -93,7 +101,7 @@
 
 #ifdef CONFIG_DEBUG_HIGHMEM
 	WARN_ON_ONCE(in_irq() && !irqs_disabled());
-	BUG_ON(idx > KM_TYPE_NR);
+	BUG_ON(idx >= KM_TYPE_NR);
 #endif
 	return idx;
 }