From f7355e99d9f71fcde093193fd4b569a648ba5ce3 Mon Sep 17 00:00:00 2001 From: David Hildenbrand Date: Fri, 21 Oct 2022 12:11:41 +0200 Subject: mm/gup: remove FOLL_MIGRATION Fortunately, the last user (KSM) is gone, so let's just remove this rather special code from generic GUP handling -- especially because KSM never required the PMD handling as KSM only deals with individual base pages. [akpm@linux-foundation.org: fix merge snafu]Link: https://lkml.kernel.org/r/20221021101141.84170-10-david@redhat.com Signed-off-by: David Hildenbrand Cc: Andrea Arcangeli Cc: Hugh Dickins Cc: Jason Gunthorpe Cc: John Hubbard Cc: Matthew Wilcox (Oracle) Cc: Peter Xu Cc: Shuah Khan Cc: Vlastimil Babka Signed-off-by: Andrew Morton --- mm/gup.c | 55 +++++-------------------------------------------------- 1 file changed, 5 insertions(+), 50 deletions(-) (limited to 'mm/gup.c') diff --git a/mm/gup.c b/mm/gup.c index 2860cf4a85e1..82b275bbaad5 100644 --- a/mm/gup.c +++ b/mm/gup.c @@ -537,30 +537,13 @@ static struct page *follow_page_pte(struct vm_area_struct *vma, if (WARN_ON_ONCE((flags & (FOLL_PIN | FOLL_GET)) == (FOLL_PIN | FOLL_GET))) return ERR_PTR(-EINVAL); -retry: if (unlikely(pmd_bad(*pmd))) return no_page_table(vma, flags); ptep = pte_offset_map_lock(mm, pmd, address, &ptl); pte = *ptep; - if (!pte_present(pte)) { - swp_entry_t entry; - /* - * KSM's break_ksm() relies upon recognizing a ksm page - * even while it is being migrated, so for that case we - * need migration_entry_wait(). - */ - if (likely(!(flags & FOLL_MIGRATION))) - goto no_page; - if (pte_none(pte)) - goto no_page; - entry = pte_to_swp_entry(pte); - if (!is_migration_entry(entry)) - goto no_page; - pte_unmap_unlock(ptep, ptl); - migration_entry_wait(mm, pmd, address); - goto retry; - } + if (!pte_present(pte)) + goto no_page; if (pte_protnone(pte) && !gup_can_follow_protnone(flags)) goto no_page; @@ -668,28 +651,8 @@ static struct page *follow_pmd_mask(struct vm_area_struct *vma, pmdval = READ_ONCE(*pmd); if (pmd_none(pmdval)) return no_page_table(vma, flags); -retry: - if (!pmd_present(pmdval)) { - /* - * Should never reach here, if thp migration is not supported; - * Otherwise, it must be a thp migration entry. - */ - VM_BUG_ON(!thp_migration_supported() || - !is_pmd_migration_entry(pmdval)); - - if (likely(!(flags & FOLL_MIGRATION))) - return no_page_table(vma, flags); - - pmd_migration_entry_wait(mm, pmd); - pmdval = READ_ONCE(*pmd); - /* - * MADV_DONTNEED may convert the pmd to null because - * mmap_lock is held in read mode - */ - if (pmd_none(pmdval)) - return no_page_table(vma, flags); - goto retry; - } + if (!pmd_present(pmdval)) + return no_page_table(vma, flags); if (pmd_devmap(pmdval)) { ptl = pmd_lock(mm, pmd); page = follow_devmap_pmd(vma, address, pmd, flags, &ctx->pgmap); @@ -703,18 +666,10 @@ retry: if (pmd_protnone(pmdval) && !gup_can_follow_protnone(flags)) return no_page_table(vma, flags); -retry_locked: ptl = pmd_lock(mm, pmd); - if (unlikely(pmd_none(*pmd))) { - spin_unlock(ptl); - return no_page_table(vma, flags); - } if (unlikely(!pmd_present(*pmd))) { spin_unlock(ptl); - if (likely(!(flags & FOLL_MIGRATION))) - return no_page_table(vma, flags); - pmd_migration_entry_wait(mm, pmd); - goto retry_locked; + return no_page_table(vma, flags); } if (unlikely(!pmd_trans_huge(*pmd))) { spin_unlock(ptl); -- cgit v1.2.3-58-ga151