From: Kefeng Wang wangkefeng.wang@huawei.com
mainline inclusion from mainline-v6.11-rc1 commit 528815392f873f0af8c6cdc279c89bd0154cbf6a category: feature bugzilla: https://gitee.com/openeuler/kernel/issues/IAROKE CVE: NA
Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?i...
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The folio refcount check is moved out for both !mapping and mapping folio, also update comment from page to folio for folio_migrate_mapping().
No functional change intended.
Link: https://lkml.kernel.org/r/20240626085328.608006-4-wangkefeng.wang@huawei.com Signed-off-by: Kefeng Wang wangkefeng.wang@huawei.com Cc: Alistair Popple apopple@nvidia.com Cc: Benjamin LaHaise bcrl@kvack.org Cc: David Hildenbrand david@redhat.com Cc: Hugh Dickins hughd@google.com Cc: Jane Chu jane.chu@oracle.com Cc: Jérôme Glisse jglisse@redhat.com Cc: Jiaqi Yan jiaqiyan@google.com Cc: Lance Yang ioworker0@gmail.com Cc: Matthew Wilcox (Oracle) willy@infradead.org Cc: Miaohe Lin linmiaohe@huawei.com Cc: Muchun Song muchun.song@linux.dev Cc: Naoya Horiguchi nao.horiguchi@gmail.com Cc: Oscar Salvador osalvador@suse.de Cc: Tony Luck tony.luck@intel.com Cc: Vishal Moola (Oracle) vishal.moola@gmail.com Signed-off-by: Andrew Morton akpm@linux-foundation.org Signed-off-by: Tong Tiangen tongtiangen@huawei.com --- mm/migrate.c | 38 ++++++++++++++++++++++---------------- 1 file changed, 22 insertions(+), 16 deletions(-)
diff --git a/mm/migrate.c b/mm/migrate.c index 00530c0b9405..f716005e15e6 100644 --- a/mm/migrate.c +++ b/mm/migrate.c @@ -391,28 +391,23 @@ static int folio_expected_refs(struct address_space *mapping, }
/* - * Replace the page in the mapping. + * Replace the folio in the mapping. * * The number of remaining references must be: - * 1 for anonymous pages without a mapping - * 2 for pages with a mapping - * 3 for pages with a mapping and PagePrivate/PagePrivate2 set. + * 1 for anonymous folios without a mapping + * 2 for folios with a mapping + * 3 for folios with a mapping and PagePrivate/PagePrivate2 set. */ -int folio_migrate_mapping(struct address_space *mapping, - struct folio *newfolio, struct folio *folio, int extra_count) +static int __folio_migrate_mapping(struct address_space *mapping, + struct folio *newfolio, struct folio *folio, int expected_count) { XA_STATE(xas, &mapping->i_pages, folio_index(folio)); struct zone *oldzone, *newzone; int dirty; - int expected_count = folio_expected_refs(mapping, folio) + extra_count; long nr = folio_nr_pages(folio); long entries, i;
if (!mapping) { - /* Anonymous page without mapping */ - if (folio_ref_count(folio) != expected_count) - return -EAGAIN; - /* Take off deferred split queue while frozen and memcg set */ if (folio_test_large(folio) && folio_test_large_rmappable(folio)) { @@ -462,7 +457,7 @@ int folio_migrate_mapping(struct address_space *mapping, entries = 1; }
- /* Move dirty while page refs frozen and newpage not yet exposed */ + /* Move dirty while folio refs frozen and newfolio not yet exposed */ dirty = folio_test_dirty(folio); if (dirty) { folio_clear_dirty(folio); @@ -476,7 +471,7 @@ int folio_migrate_mapping(struct address_space *mapping, }
/* - * Drop cache reference from old page by unfreezing + * Drop cache reference from old folio by unfreezing * to one less reference. * We know this isn't the last reference. */ @@ -492,11 +487,11 @@ int folio_migrate_mapping(struct address_space *mapping,
/* * If moved to a different zone then also account - * the page for that zone. Other VM counters will be + * the folio for that zone. Other VM counters will be * taken care of when we establish references to the - * new page and drop references to the old page. + * new folio and drop references to the old folio. * - * Note that anonymous pages are accounted for + * Note that anonymous folios are accounted for * via NR_FILE_PAGES and NR_ANON_MAPPED if they * are mapped to swap space. */ @@ -536,6 +531,17 @@ int folio_migrate_mapping(struct address_space *mapping,
return MIGRATEPAGE_SUCCESS; } + +int folio_migrate_mapping(struct address_space *mapping, + struct folio *newfolio, struct folio *folio, int extra_count) +{ + int expected_count = folio_expected_refs(mapping, folio) + extra_count; + + if (folio_ref_count(folio) != expected_count) + return -EAGAIN; + + return __folio_migrate_mapping(mapping, newfolio, folio, expected_count); +} EXPORT_SYMBOL(folio_migrate_mapping);
/*