linux-kernel - [PATCH v3 1/5] mm: move memcmp_pages() and pages

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Message-ID: <20190612220320.2223898-2-songliubraving@fb.com>
Date:   Wed, 12 Jun 2019 15:03:15 -0700
From:   Song Liu <songliubraving@...com>
To:     <linux-kernel@...r.kernel.org>, <linux-mm@...ck.org>
CC:     <namit@...are.com>, <peterz@...radead.org>, <oleg@...hat.com>,
        <rostedt@...dmis.org>, <mhiramat@...nel.org>,
        <matthew.wilcox@...cle.com>, <kirill.shutemov@...ux.intel.com>,
        <kernel-team@...com>, Song Liu <songliubraving@...com>
Subject: [PATCH v3 1/5] mm: move memcmp_pages() and pages_identical()

This patch moves memcmp_pages() to mm/util.c and pages_identical() to
mm.h, so that we can use them in other files.

Signed-off-by: Song Liu <songliubraving@...com>
---
 include/linux/mm.h |  7 +++++++
 mm/ksm.c           | 18 ------------------
 mm/util.c          | 13 +++++++++++++
 3 files changed, 20 insertions(+), 18 deletions(-)

diff --git a/include/linux/mm.h b/include/linux/mm.h
index dd0b5f4e1e45..0ab8c7d84cd0 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -2891,5 +2891,12 @@ void __init setup_nr_node_ids(void);
 static inline void setup_nr_node_ids(void) {}
 #endif
 
+extern int memcmp_pages(struct page *page1, struct page *page2);
+
+static inline int pages_identical(struct page *page1, struct page *page2)
+{
+	return !memcmp_pages(page1, page2);
+}
+
 #endif /* __KERNEL__ */
 #endif /* _LINUX_MM_H */
diff --git a/mm/ksm.c b/mm/ksm.c
index 81c20ed57bf6..6f153f976c4c 100644
--- a/mm/ksm.c
+++ b/mm/ksm.c
@@ -1030,24 +1030,6 @@ static u32 calc_checksum(struct page *page)
 	return checksum;
 }
 
-static int memcmp_pages(struct page *page1, struct page *page2)
-{
-	char *addr1, *addr2;
-	int ret;
-
-	addr1 = kmap_atomic(page1);
-	addr2 = kmap_atomic(page2);
-	ret = memcmp(addr1, addr2, PAGE_SIZE);
-	kunmap_atomic(addr2);
-	kunmap_atomic(addr1);
-	return ret;
-}
-
-static inline int pages_identical(struct page *page1, struct page *page2)
-{
-	return !memcmp_pages(page1, page2);
-}
-
 static int write_protect_page(struct vm_area_struct *vma, struct page *page,
 			      pte_t *orig_pte)
 {
diff --git a/mm/util.c b/mm/util.c
index 9834c4ab7d8e..750e586d50bc 100644
--- a/mm/util.c
+++ b/mm/util.c
@@ -755,3 +755,16 @@ int get_cmdline(struct task_struct *task, char *buffer, int buflen)
 out:
 	return res;
 }
+
+int memcmp_pages(struct page *page1, struct page *page2)
+{
+	char *addr1, *addr2;
+	int ret;
+
+	addr1 = kmap_atomic(page1);
+	addr2 = kmap_atomic(page2);
+	ret = memcmp(addr1, addr2, PAGE_SIZE);
+	kunmap_atomic(addr2);
+	kunmap_atomic(addr1);
+	return ret;
+}
-- 
2.17.1