Matthew Wilcox reported that, while he was looking at memmove_page(), he
realized that it can't actually work.
The reasons are hidden in its implementation, which makes use of
memmove() on logical addresses provided by kmap_local_page(). memmove()
does the wrong thing when it tests "if (dest <= src)".
Therefore, delete memmove_page().
No need to change any other code because we have no call sites of
memmove_page() across the whole kernel.
Reported-by: Matthew Wilcox <willy@xxxxxxxxxxxxx>
Cc: Ira Weiny <ira.weiny@xxxxxxxxx>
Signed-off-by: Fabio M. De Francesco <fmdefrancesco@xxxxxxxxx>
---
include/linux/highmem.h | 13 -------------
1 file changed, 13 deletions(-)
diff --git a/include/linux/highmem.h b/include/linux/highmem.h
index 3af34de54330..fee9835e3793 100644
--- a/include/linux/highmem.h
+++ b/include/linux/highmem.h
@@ -336,19 +336,6 @@ static inline void memcpy_page(struct page *dst_page, size_t dst_off,
kunmap_local(dst);
}
-static inline void memmove_page(struct page *dst_page, size_t dst_off,
- struct page *src_page, size_t src_off,
- size_t len)
-{
- char *dst = kmap_local_page(dst_page);
- char *src = kmap_local_page(src_page);
-
- VM_BUG_ON(dst_off + len > PAGE_SIZE || src_off + len > PAGE_SIZE);
- memmove(dst + dst_off, src + src_off, len);
- kunmap_local(src);
- kunmap_local(dst);
-}
-
static inline void memset_page(struct page *page, size_t offset, int val,
size_t len)
{
--
2.36.1
