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authorMuchun Song <songmuchun@bytedance.com>2022-08-19 11:55:32 +0800
committerAndrew Morton <akpm@linux-foundation.org>2022-09-11 20:25:58 -0700
commit33febb519d673b9f574903764f13f47e65328ca5 (patch)
tree3217f129c5ebe80905a6cb0d6a8631e242cd012d /mm/hugetlb_vmemmap.c
parente9ff3ba7ff10490a92792faf1d3573a24fc6e5c9 (diff)
downloadlwn-33febb519d673b9f574903764f13f47e65328ca5.tar.gz
lwn-33febb519d673b9f574903764f13f47e65328ca5.zip
mm: hugetlb_vmemmap: simplify reset_struct_pages()
We can choose to copy three contiguous tail pages' content to the first three pages instead of copying one by one to simplify the code and reduce code size from 229 bytes to 63 bytes. The BUILD_BUG_ON() aims to avoid out-of-bounds accesses. Link: https://lkml.kernel.org/r/20220819035532.6189-1-songmuchun@bytedance.com Signed-off-by: Muchun Song <songmuchun@bytedance.com> Reviewed-by: Miaohe Lin <linmiaohe@huawei.com> Cc: Mike Kravetz <mike.kravetz@oracle.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Diffstat (limited to 'mm/hugetlb_vmemmap.c')
-rw-r--r--mm/hugetlb_vmemmap.c5
1 files changed, 2 insertions, 3 deletions
diff --git a/mm/hugetlb_vmemmap.c b/mm/hugetlb_vmemmap.c
index 76b2d03a0d8d..ba2a2596fb4e 100644
--- a/mm/hugetlb_vmemmap.c
+++ b/mm/hugetlb_vmemmap.c
@@ -265,11 +265,10 @@ static void vmemmap_remap_pte(pte_t *pte, unsigned long addr,
static inline void reset_struct_pages(struct page *start)
{
- int i;
struct page *from = start + NR_RESET_STRUCT_PAGE;
- for (i = 0; i < NR_RESET_STRUCT_PAGE; i++)
- memcpy(start + i, from, sizeof(*from));
+ BUILD_BUG_ON(NR_RESET_STRUCT_PAGE * 2 > PAGE_SIZE / sizeof(struct page));
+ memcpy(start, from, sizeof(*from) * NR_RESET_STRUCT_PAGE);
}
static void vmemmap_restore_pte(pte_t *pte, unsigned long addr,