From: David Hildenbrand david@redhat.com
mainline inclusion from mainline-v6.8-rc1 commit 44887f39945519fa8405133b1acd098fda9c9746 category: feature bugzilla: https://gitee.com/openeuler/kernel/issues/I9CESE CVE: NA
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hugetlb rmap handling differs quite a lot from "ordinary" rmap code. For example, hugetlb currently only supports entire mappings, and treats any mapping as mapped using a single "logical PTE". Let's move it out of the way so we can overhaul our "ordinary" rmap. implementation/interface.
Right now we're using page_dup_file_rmap() in some cases where "ordinary" rmap code would have used page_add_file_rmap(). So let's introduce and use hugetlb_add_file_rmap() instead. We won't be adding a "hugetlb_dup_file_rmap()" functon for the fork() case, as it would be doing the same: "dup" is just an optimization for "add".
What remains is a single page_dup_file_rmap() call in fork() code.
Add sanity checks that we end up with the right folios in the right functions.
Link: https://lkml.kernel.org/r/20231220224504.646757-4-david@redhat.com Signed-off-by: David Hildenbrand david@redhat.com Reviewed-by: Yin Fengwei fengwei.yin@intel.com Reviewed-by: Ryan Roberts ryan.roberts@arm.com Reviewed-by: Muchun Song songmuchun@bytedance.com Cc: Hugh Dickins hughd@google.com Cc: Matthew Wilcox (Oracle) willy@infradead.org Cc: Muchun Song muchun.song@linux.dev Cc: Peter Xu peterx@redhat.com Signed-off-by: Andrew Morton akpm@linux-foundation.org (cherry picked from commit 44887f39945519fa8405133b1acd098fda9c9746) Signed-off-by: Kefeng Wang wangkefeng.wang@huawei.com --- include/linux/rmap.h | 8 ++++++++ mm/hugetlb.c | 6 +++--- mm/migrate.c | 2 +- mm/rmap.c | 1 + 4 files changed, 13 insertions(+), 4 deletions(-)
diff --git a/include/linux/rmap.h b/include/linux/rmap.h index 556366dafa8f..74a5f4d3979f 100644 --- a/include/linux/rmap.h +++ b/include/linux/rmap.h @@ -208,6 +208,14 @@ void hugetlb_add_anon_rmap(struct folio *, struct vm_area_struct *, void hugetlb_add_new_anon_rmap(struct folio *, struct vm_area_struct *, unsigned long address);
+static inline void hugetlb_add_file_rmap(struct folio *folio) +{ + VM_WARN_ON_FOLIO(!folio_test_hugetlb(folio), folio); + VM_WARN_ON_FOLIO(folio_test_anon(folio), folio); + + atomic_inc(&folio->_entire_mapcount); +} + static inline void hugetlb_remove_rmap(struct folio *folio) { VM_WARN_ON_FOLIO(!folio_test_hugetlb(folio), folio); diff --git a/mm/hugetlb.c b/mm/hugetlb.c index c6e9b3f7d542..0b3d6af04079 100644 --- a/mm/hugetlb.c +++ b/mm/hugetlb.c @@ -5353,7 +5353,7 @@ int copy_hugetlb_page_range(struct mm_struct *dst, struct mm_struct *src, * sleep during the process. */ if (!folio_test_anon(pte_folio)) { - page_dup_file_rmap(&pte_folio->page, true); + hugetlb_add_file_rmap(pte_folio); } else if (page_try_dup_anon_rmap(&pte_folio->page, true, src_vma)) { pte_t src_pte_old = entry; @@ -6230,7 +6230,7 @@ static vm_fault_t hugetlb_no_page(struct mm_struct *mm, if (anon_rmap) hugetlb_add_new_anon_rmap(folio, vma, haddr); else - page_dup_file_rmap(&folio->page, true); + hugetlb_add_file_rmap(folio); new_pte = make_huge_pte(vma, &folio->page, ((vma->vm_flags & VM_WRITE) && (vma->vm_flags & VM_SHARED))); /* @@ -6654,7 +6654,7 @@ int hugetlb_mfill_atomic_pte(pte_t *dst_pte, goto out_release_unlock;
if (folio_in_pagecache) - page_dup_file_rmap(&folio->page, true); + hugetlb_add_file_rmap(folio); else hugetlb_add_new_anon_rmap(folio, dst_vma, dst_addr);
diff --git a/mm/migrate.c b/mm/migrate.c index 84f1e46355a8..49270a60deb5 100644 --- a/mm/migrate.c +++ b/mm/migrate.c @@ -252,7 +252,7 @@ static bool remove_migration_pte(struct folio *folio, hugetlb_add_anon_rmap(folio, vma, pvmw.address, rmap_flags); else - page_dup_file_rmap(new, true); + hugetlb_add_file_rmap(folio); set_huge_pte_at(vma->vm_mm, pvmw.address, pvmw.pte, pte, psize); } else diff --git a/mm/rmap.c b/mm/rmap.c index 460c589b7720..ef7979695ef3 100644 --- a/mm/rmap.c +++ b/mm/rmap.c @@ -1365,6 +1365,7 @@ void folio_add_file_rmap_range(struct folio *folio, struct page *page, unsigned int nr_pmdmapped = 0, first; int nr = 0;
+ VM_WARN_ON_FOLIO(folio_test_hugetlb(folio), folio); VM_WARN_ON_FOLIO(compound && !folio_test_pmd_mappable(folio), folio);
/* Is page being mapped by PTE? Is this its first map to be added? */