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| author | ZhangPeng <zhangpeng362@huawei.com> | 2023-04-10 21:39:28 +0800 |
|---|---|---|
| committer | Andrew Morton <akpm@linux-foundation.org> | 2023-04-18 16:29:54 -0700 |
| commit | 0d508c1f0e2c7cec76c141e9d2ebc3020d9e4be4 (patch) | |
| tree | d5ceb89ac42b0cf3f5a67ca96dcf8d15ed2f9115 /mm | |
| parent | 07e6d4095c75bcf0bf511b36eecaceb3fbb91ad9 (diff) | |
| download | lwn-0d508c1f0e2c7cec76c141e9d2ebc3020d9e4be4.tar.gz lwn-0d508c1f0e2c7cec76c141e9d2ebc3020d9e4be4.zip | |
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 <zhangpeng362@huawei.com>
Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Kefeng Wang <wangkefeng.wang@huawei.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Nanyong Sun <sunnanyong@huawei.com>
Cc: Sidhartha Kumar <sidhartha.kumar@oracle.com>
Cc: Vishal Moola (Oracle) <vishal.moola@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Diffstat (limited to 'mm')
| -rw-r--r-- | mm/memory.c | 14 |
1 files 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) |