From 9384d79249d04b03572abb7e551a35d99c9268c0 Mon Sep 17 00:00:00 2001 From: "Fabio M. De Francesco" Date: Mon, 6 Jun 2022 16:15:33 +0200 Subject: [PATCH] mm/highmem: delete memmove_page() 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. Link: https://lkml.kernel.org/r/20220606141533.555-1-fmdefrancesco@gmail.com Signed-off-by: Fabio M. De Francesco Reported-by: Matthew Wilcox Reviewed-by: Baoquan He Reviewed-by: Ira Weiny Cc: Sebastian Andrzej Siewior Signed-off-by: Andrew Morton --- include/linux/highmem.h | 13 ------------- 1 file changed, 13 deletions(-) diff --git a/include/linux/highmem.h b/include/linux/highmem.h index 3af34de54330c..fee9835e37931 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) { -- 2.30.2