From 0d508c1f0e2c7cec76c141e9d2ebc3020d9e4be4 Mon Sep 17 00:00:00 2001 From: ZhangPeng Date: Mon, 10 Apr 2023 21:39:28 +0800 Subject: [PATCH] userfaultfd: use kmap_local_page() in copy_huge_page_from_user() kmap() and kmap_atomic() are being deprecated in favor of kmap_local_page() which is appropriate for any thread local context.[1] Let's replace the kmap() and kmap_atomic() with kmap_local_page() in copy_huge_page_from_user(). When allow_pagefault is false, disable page faults to prevent potential deadlock.[2] [1] https://lore.kernel.org/all/20220813220034.806698-1-ira.weiny@intel.com/ [2] https://lkml.kernel.org/r/20221025220136.2366143-1-ira.weiny@intel.com Link: https://lkml.kernel.org/r/20230410133932.32288-3-zhangpeng362@huawei.com Signed-off-by: ZhangPeng Reviewed-by: Mike Kravetz Cc: Kefeng Wang Cc: Matthew Wilcox Cc: Muchun Song Cc: Nanyong Sun Cc: Sidhartha Kumar Cc: Vishal Moola (Oracle) Signed-off-by: Andrew Morton --- mm/memory.c | 14 ++++++-------- 1 file changed, 6 insertions(+), 8 deletions(-) diff --git a/mm/memory.c b/mm/memory.c index 387226d6094d..808f354bce65 100644 --- a/mm/memory.c +++ b/mm/memory.c @@ -5880,16 +5880,14 @@ long copy_huge_page_from_user(struct page *dst_page, for (i = 0; i < pages_per_huge_page; i++) { subpage = nth_page(dst_page, i); - if (allow_pagefault) - page_kaddr = kmap(subpage); - else - page_kaddr = kmap_atomic(subpage); + page_kaddr = kmap_local_page(subpage); + if (!allow_pagefault) + pagefault_disable(); rc = copy_from_user(page_kaddr, usr_src + i * PAGE_SIZE, PAGE_SIZE); - if (allow_pagefault) - kunmap(subpage); - else - kunmap_atomic(page_kaddr); + if (!allow_pagefault) + pagefault_enable(); + kunmap_local(page_kaddr); ret_val -= (PAGE_SIZE - rc); if (rc) -- 2.11.0