[PATCH uprobe, thp v2 1/5] mm: move memcmp_pages() and pages_identical()

From: Song Liu
Date: Tue Jun 04 2019 - 12:55:51 EST


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@xxxxxx>
---
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 0f57b5dfb331..1bdaf1872492 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -2881,5 +2881,12 @@ 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 c2fb8fd807df..c122718de550 100644
--- a/mm/util.c
+++ b/mm/util.c
@@ -801,3 +801,16 @@ 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