From: Barry Song <v-songbaohua@oppo.com> mainline inclusion from mainline-v6.11-rc1 commit 3f9abcaa3e9c3910893ccbe6085aa0452e72896d category: feature bugzilla: https://gitee.com/openeuler/kernel/issues/IAJ5MT Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?i... -------------------------------- There could arise a necessity to obtain the first pte_t from a swap pte_t located in the middle. For instance, this may occur within the context of do_swap_page(), where a page fault can potentially occur in any PTE of a large folio. To address this, the following patch introduces pte_move_swp_offset(), a function capable of bidirectional movement by a specified delta argument. Consequently, pte_next_swp_offset() will directly invoke it with delta = 1. Link: https://lkml.kernel.org/r/20240529082824.150954-4-21cnbao@gmail.com Signed-off-by: Barry Song <v-songbaohua@oppo.com> Suggested-by: "Huang, Ying" <ying.huang@intel.com> Reviewed-by: Ryan Roberts <ryan.roberts@arm.com> Reviewed-by: "Huang, Ying" <ying.huang@intel.com> Cc: Andreas Larsson <andreas@gaisler.com> Cc: Baolin Wang <baolin.wang@linux.alibaba.com> Cc: Chris Li <chrisl@kernel.org> Cc: Christoph Hellwig <hch@infradead.org> Cc: Chuanhua Han <hanchuanhua@oppo.com> Cc: David Hildenbrand <david@redhat.com> Cc: "David S. Miller" <davem@davemloft.net> Cc: Gao Xiang <xiang@kernel.org> Cc: Hugh Dickins <hughd@google.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Kairui Song <kasong@tencent.com> Cc: Khalid Aziz <khalid.aziz@oracle.com> Cc: Len Brown <len.brown@intel.com> Cc: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: Pavel Machek <pavel@ucw.cz> Cc: "Rafael J. Wysocki" <rafael@kernel.org> Cc: Suren Baghdasaryan <surenb@google.com> Cc: Yosry Ahmed <yosryahmed@google.com> Cc: Yu Zhao <yuzhao@google.com> Cc: Zi Yan <ziy@nvidia.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Liu Shixin <liushixin2@huawei.com> --- mm/internal.h | 25 +++++++++++++++++++++---- 1 file changed, 21 insertions(+), 4 deletions(-) diff --git a/mm/internal.h b/mm/internal.h index 6479c376ffdf8..e5b541e3f67e5 100644 --- a/mm/internal.h +++ b/mm/internal.h @@ -208,18 +208,21 @@ static inline int folio_pte_batch(struct folio *folio, unsigned long addr, } /** - * pte_next_swp_offset - Increment the swap entry offset field of a swap pte. + * pte_move_swp_offset - Move the swap entry offset field of a swap pte + * forward or backward by delta * @pte: The initial pte state; is_swap_pte(pte) must be true and * non_swap_entry() must be false. + * @delta: The direction and the offset we are moving; forward if delta + * is positive; backward if delta is negative * - * Increments the swap offset, while maintaining all other fields, including + * Moves the swap offset, while maintaining all other fields, including * swap type, and any swp pte bits. The resulting pte is returned. */ -static inline pte_t pte_next_swp_offset(pte_t pte) +static inline pte_t pte_move_swp_offset(pte_t pte, long delta) { swp_entry_t entry = pte_to_swp_entry(pte); pte_t new = __swp_entry_to_pte(__swp_entry(swp_type(entry), - (swp_offset(entry) + 1))); + (swp_offset(entry) + delta))); if (pte_swp_soft_dirty(pte)) new = pte_swp_mksoft_dirty(new); @@ -231,6 +234,20 @@ static inline pte_t pte_next_swp_offset(pte_t pte) return new; } + +/** + * pte_next_swp_offset - Increment the swap entry offset field of a swap pte. + * @pte: The initial pte state; is_swap_pte(pte) must be true and + * non_swap_entry() must be false. + * + * Increments the swap offset, while maintaining all other fields, including + * swap type, and any swp pte bits. The resulting pte is returned. + */ +static inline pte_t pte_next_swp_offset(pte_t pte) +{ + return pte_move_swp_offset(pte, 1); +} + /** * swap_pte_batch - detect a PTE batch for a set of contiguous swap entries * @start_ptep: Page table pointer for the first entry. -- 2.25.1