From: Miaohe Lin <linmiaohe@xxxxxxxxxx> Subject: mm/memory-failure.c: rework the try_to_unmap logic in hwpoison_user_mappings() Only for hugetlb pages in shared mappings, try_to_unmap should take semaphore in write mode here. Rework the code to make it clear. Link: https://lkml.kernel.org/r/20220218090118.1105-7-linmiaohe@xxxxxxxxxx Signed-off-by: Miaohe Lin <linmiaohe@xxxxxxxxxx> Acked-by: Naoya Horiguchi <naoya.horiguchi@xxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- mm/memory-failure.c | 34 +++++++++++++++------------------- 1 file changed, 15 insertions(+), 19 deletions(-) --- a/mm/memory-failure.c~mm-memory-failurec-rework-the-try_to_unmap-logic-in-hwpoison_user_mappings +++ a/mm/memory-failure.c @@ -1404,26 +1404,22 @@ static bool hwpoison_user_mappings(struc if (kill) collect_procs(hpage, &tokill, flags & MF_ACTION_REQUIRED); - if (!PageHuge(hpage)) { - try_to_unmap(hpage, ttu); + if (PageHuge(hpage) && !PageAnon(hpage)) { + /* + * For hugetlb pages in shared mappings, try_to_unmap + * could potentially call huge_pmd_unshare. Because of + * this, take semaphore in write mode here and set + * TTU_RMAP_LOCKED to indicate we have taken the lock + * at this higher level. + */ + mapping = hugetlb_page_mapping_lock_write(hpage); + if (mapping) { + try_to_unmap(hpage, ttu|TTU_RMAP_LOCKED); + i_mmap_unlock_write(mapping); + } else + pr_info("Memory failure: %#lx: could not lock mapping for mapped huge page\n", pfn); } else { - if (!PageAnon(hpage)) { - /* - * For hugetlb pages in shared mappings, try_to_unmap - * could potentially call huge_pmd_unshare. Because of - * this, take semaphore in write mode here and set - * TTU_RMAP_LOCKED to indicate we have taken the lock - * at this higher level. - */ - mapping = hugetlb_page_mapping_lock_write(hpage); - if (mapping) { - try_to_unmap(hpage, ttu|TTU_RMAP_LOCKED); - i_mmap_unlock_write(mapping); - } else - pr_info("Memory failure: %#lx: could not lock mapping for mapped huge page\n", pfn); - } else { - try_to_unmap(hpage, ttu); - } + try_to_unmap(hpage, ttu); } unmap_success = !page_mapped(hpage); _
