From 11bf19bc0eb48735772e664d07573f916f6e3f29 Mon Sep 17 00:00:00 2001
From: Andrew Morton <akpm@zip.com.au>
Date: Tue, 3 Sep 2002 05:33:46 -0700
Subject: [PATCH] [PATCH] place rmap locking in rmap-locking.h

The rmap locking inlines are causing some header file
dependency/ordering problems - move them out of page-flags.h and into
their own header file.
---
 include/linux/page-flags.h   | 30 ------------------------------
 include/linux/rmap-locking.h | 33 +++++++++++++++++++++++++++++++++
 mm/rmap.c                    |  1 +
 mm/vmscan.c                  |  1 +
 4 files changed, 35 insertions(+), 30 deletions(-)
 create mode 100644 include/linux/rmap-locking.h

diff --git a/include/linux/page-flags.h b/include/linux/page-flags.h
index 5a49020e728b..2b2eb67ae7a8 100644
--- a/include/linux/page-flags.h
+++ b/include/linux/page-flags.h
@@ -228,36 +228,6 @@ extern void get_page_state(struct page_state *ret);
 #define ClearPageDirect(page)		clear_bit(PG_direct, &(page)->flags)
 #define TestClearPageDirect(page)	test_and_clear_bit(PG_direct, &(page)->flags)
 
-/*
- * inlines for acquisition and release of PG_chainlock
- */
-static inline void pte_chain_lock(struct page *page)
-{
-	/*
-	 * Assuming the lock is uncontended, this never enters
-	 * the body of the outer loop. If it is contended, then
-	 * within the inner loop a non-atomic test is used to
-	 * busywait with less bus contention for a good time to
-	 * attempt to acquire the lock bit.
-	 */
-	preempt_disable();
-#ifdef CONFIG_SMP
-	while (test_and_set_bit(PG_chainlock, &page->flags)) {
-		while (test_bit(PG_chainlock, &page->flags))
-			cpu_relax();
-	}
-#endif
-}
-
-static inline void pte_chain_unlock(struct page *page)
-{
-#ifdef CONFIG_SMP
-	smp_mb__before_clear_bit();
-	clear_bit(PG_chainlock, &page->flags);
-#endif
-	preempt_enable();
-}
-
 /*
  * The PageSwapCache predicate doesn't use a PG_flag at this time,
  * but it may again do so one day.
diff --git a/include/linux/rmap-locking.h b/include/linux/rmap-locking.h
new file mode 100644
index 000000000000..302a58f54ca3
--- /dev/null
+++ b/include/linux/rmap-locking.h
@@ -0,0 +1,33 @@
+/*
+ * include/linux/rmap-locking.h
+ *
+ * Locking primitives for exclusive access to a page's reverse-mapping
+ * pte chain.
+ */
+
+static inline void pte_chain_lock(struct page *page)
+{
+	/*
+	 * Assuming the lock is uncontended, this never enters
+	 * the body of the outer loop. If it is contended, then
+	 * within the inner loop a non-atomic test is used to
+	 * busywait with less bus contention for a good time to
+	 * attempt to acquire the lock bit.
+	 */
+	preempt_disable();
+#ifdef CONFIG_SMP
+	while (test_and_set_bit(PG_chainlock, &page->flags)) {
+		while (test_bit(PG_chainlock, &page->flags))
+			cpu_relax();
+	}
+#endif
+}
+
+static inline void pte_chain_unlock(struct page *page)
+{
+#ifdef CONFIG_SMP
+	smp_mb__before_clear_bit();
+	clear_bit(PG_chainlock, &page->flags);
+#endif
+	preempt_enable();
+}
diff --git a/mm/rmap.c b/mm/rmap.c
index 727e50efca39..5c98c1758dea 100644
--- a/mm/rmap.c
+++ b/mm/rmap.c
@@ -25,6 +25,7 @@
 #include <linux/swapops.h>
 #include <linux/slab.h>
 #include <linux/init.h>
+#include <linux/rmap-locking.h>
 
 #include <asm/pgalloc.h>
 #include <asm/rmap.h>
diff --git a/mm/vmscan.c b/mm/vmscan.c
index 41712a97b079..a00fe27159d9 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -25,6 +25,7 @@
 #include <linux/buffer_head.h>		/* for try_to_release_page() */
 #include <linux/mm_inline.h>
 #include <linux/pagevec.h>
+#include <linux/rmap-locking.h>
 
 #include <asm/pgalloc.h>
 #include <asm/tlbflush.h>
-- 
2.39.5