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 /* SPDX-License-Identifier: GPL-2.0 */
 #ifndef LINUX_MM_INLINE_H
 #define LINUX_MM_INLINE_H
 
 #include <linux/atomic.h>
 #include <linux/huge_mm.h>
 #include <linux/swap.h>
 #include <linux/string.h>
 #include <linux/userfaultfd_k.h>
 #include <linux/swapops.h>
 
 /**
  * folio_is_file_lru - Should the folio be on a file LRU or anon LRU?
  * @folio: The folio to test.
  *
  * We would like to get this info without a page flag, but the state
  * needs to survive until the folio is last deleted from the LRU, which
  * could be as far down as __page_cache_release.
  *
  * Return: An integer (not a boolean!) used to sort a folio onto the
  * right LRU list and to account folios correctly.
  * 1 if @folio is a regular filesystem backed page cache folio
  * or a lazily freed anonymous folio (e.g. via MADV_FREE).
  * 0 if @folio is a normal anonymous folio, a tmpfs folio or otherwise
  * ram or swap backed folio.
  */
 static inline int folio_is_file_lru(struct folio *folio)
 {
     return !folio_test_swapbacked(folio);
 }
 
 static inline int page_is_file_lru(struct page *page)
 {
     return folio_is_file_lru(page_folio(page));
 }
 
 static __always_inline void update_lru_size(struct lruvec *lruvec,
                 enum lru_list lru, enum zone_type zid,
                 long nr_pages)
 {
     struct pglist_data *pgdat = lruvec_pgdat(lruvec);
 
     __mod_lruvec_state(lruvec, NR_LRU_BASE + lru, nr_pages);
     __mod_zone_page_state(&pgdat->node_zones[zid],
                 NR_ZONE_LRU_BASE + lru, nr_pages);
 #ifdef CONFIG_MEMCG
     mem_cgroup_update_lru_size(lruvec, lru, zid, nr_pages);
 #endif
 }
 
 /**
  * __folio_clear_lru_flags - Clear page lru flags before releasing a page.
  * @folio: The folio that was on lru and now has a zero reference.
  */
 static __always_inline void __folio_clear_lru_flags(struct folio *folio)
 {
     VM_BUG_ON_FOLIO(!folio_test_lru(folio), folio);
 
     __folio_clear_lru(folio);
 
     /* this shouldn't happen, so leave the flags to bad_page() */
     if (folio_test_active(folio) && folio_test_unevictable(folio))
         return;
 
     __folio_clear_active(folio);
     __folio_clear_unevictable(folio);
 }
 
 static __always_inline void __clear_page_lru_flags(struct page *page)
 {
     __folio_clear_lru_flags(page_folio(page));
 }
 
 /**
  * folio_lru_list - Which LRU list should a folio be on?
  * @folio: The folio to test.
  *
  * Return: The LRU list a folio should be on, as an index
  * into the array of LRU lists.
  */
 static __always_inline enum lru_list folio_lru_list(struct folio *folio)
 {
     enum lru_list lru;
 
     VM_BUG_ON_FOLIO(folio_test_active(folio) && folio_test_unevictable(folio), folio);
 
     if (folio_test_unevictable(folio))
         return LRU_UNEVICTABLE;
 
     lru = folio_is_file_lru(folio) ? LRU_INACTIVE_FILE : LRU_INACTIVE_ANON;
     if (folio_test_active(folio))
         lru += LRU_ACTIVE;
 
     return lru;
 }
 
 static __always_inline
 void lruvec_add_folio(struct lruvec *lruvec, struct folio *folio)
 {
     enum lru_list lru = folio_lru_list(folio);
 
     update_lru_size(lruvec, lru, folio_zonenum(folio),
             folio_nr_pages(folio));
     if (lru != LRU_UNEVICTABLE)
         list_add(&folio->lru, &lruvec->lists[lru]);
 }
 
 static __always_inline void add_page_to_lru_list(struct page *page,
                 struct lruvec *lruvec)
 {
     lruvec_add_folio(lruvec, page_folio(page));
 }
 
 static __always_inline
 void lruvec_add_folio_tail(struct lruvec *lruvec, struct folio *folio)
 {
     enum lru_list lru = folio_lru_list(folio);
 
     update_lru_size(lruvec, lru, folio_zonenum(folio),
             folio_nr_pages(folio));
     /* This is not expected to be used on LRU_UNEVICTABLE */
     list_add_tail(&folio->lru, &lruvec->lists[lru]);
 }
 
 static __always_inline void add_page_to_lru_list_tail(struct page *page,
                 struct lruvec *lruvec)
 {
     lruvec_add_folio_tail(lruvec, page_folio(page));
 }
 
 static __always_inline
 void lruvec_del_folio(struct lruvec *lruvec, struct folio *folio)
 {
     enum lru_list lru = folio_lru_list(folio);
 
     if (lru != LRU_UNEVICTABLE)
         list_del(&folio->lru);
     update_lru_size(lruvec, lru, folio_zonenum(folio),
             -folio_nr_pages(folio));
 }
 
 static __always_inline void del_page_from_lru_list(struct page *page,
                 struct lruvec *lruvec)
 {
     lruvec_del_folio(lruvec, page_folio(page));
 }
 
 #ifdef CONFIG_ANON_VMA_NAME
 /*
  * mmap_lock should be read-locked when calling anon_vma_name(). Caller should
  * either keep holding the lock while using the returned pointer or it should
  * raise anon_vma_name refcount before releasing the lock.
  */
 extern struct anon_vma_name *anon_vma_name(struct vm_area_struct *vma);
 extern struct anon_vma_name *anon_vma_name_alloc(const char *name);
 extern void anon_vma_name_free(struct kref *kref);
 
 /* mmap_lock should be read-locked */
 static inline void anon_vma_name_get(struct anon_vma_name *anon_name)
 {
     if (anon_name)
         kref_get(&anon_name->kref);
 }
 
 static inline void anon_vma_name_put(struct anon_vma_name *anon_name)
 {
     if (anon_name)
         kref_put(&anon_name->kref, anon_vma_name_free);
 }
 
 static inline
 struct anon_vma_name *anon_vma_name_reuse(struct anon_vma_name *anon_name)
 {
     /* Prevent anon_name refcount saturation early on */
     if (kref_read(&anon_name->kref) < REFCOUNT_MAX) {
         anon_vma_name_get(anon_name);
         return anon_name;
 
     }
     return anon_vma_name_alloc(anon_name->name);
 }
 
 static inline void dup_anon_vma_name(struct vm_area_struct *orig_vma,
                      struct vm_area_struct *new_vma)
 {
     struct anon_vma_name *anon_name = anon_vma_name(orig_vma);
 
     if (anon_name)
         new_vma->anon_name = anon_vma_name_reuse(anon_name);
 }
 
 static inline void free_anon_vma_name(struct vm_area_struct *vma)
 {
     /*
      * Not using anon_vma_name because it generates a warning if mmap_lock
      * is not held, which might be the case here.
      */
     if (!vma->vm_file)
         anon_vma_name_put(vma->anon_name);
 }
 
 static inline bool anon_vma_name_eq(struct anon_vma_name *anon_name1,
                     struct anon_vma_name *anon_name2)
 {
     if (anon_name1 == anon_name2)
         return true;
 
     return anon_name1 && anon_name2 &&
         !strcmp(anon_name1->name, anon_name2->name);
 }
 
 #else /* CONFIG_ANON_VMA_NAME */
 static inline struct anon_vma_name *anon_vma_name(struct vm_area_struct *vma)
 {
     return NULL;
 }
 
 static inline struct anon_vma_name *anon_vma_name_alloc(const char *name)
 {
     return NULL;
 }
 
 static inline void anon_vma_name_get(struct anon_vma_name *anon_name) {}
 static inline void anon_vma_name_put(struct anon_vma_name *anon_name) {}
 static inline void dup_anon_vma_name(struct vm_area_struct *orig_vma,
                      struct vm_area_struct *new_vma) {}
 static inline void free_anon_vma_name(struct vm_area_struct *vma) {}
 
 static inline bool anon_vma_name_eq(struct anon_vma_name *anon_name1,
                     struct anon_vma_name *anon_name2)
 {
     return true;
 }
 
 #endif  /* CONFIG_ANON_VMA_NAME */
 
 static inline void init_tlb_flush_pending(struct mm_struct *mm)
 {
     atomic_set(&mm->tlb_flush_pending, 0);
 }
 
 static inline void inc_tlb_flush_pending(struct mm_struct *mm)
 {
     atomic_inc(&mm->tlb_flush_pending);
     /*
      * The only time this value is relevant is when there are indeed pages
      * to flush. And we'll only flush pages after changing them, which
      * requires the PTL.
      *
      * So the ordering here is:
      *
      *  atomic_inc(&mm->tlb_flush_pending);
      *  spin_lock(&ptl);
      *  ...
      *  set_pte_at();
      *  spin_unlock(&ptl);
      *
      *              spin_lock(&ptl)
      *              mm_tlb_flush_pending();
      *              ....
      *              spin_unlock(&ptl);
      *
      *  flush_tlb_range();
      *  atomic_dec(&mm->tlb_flush_pending);
      *
      * Where the increment if constrained by the PTL unlock, it thus
      * ensures that the increment is visible if the PTE modification is
      * visible. After all, if there is no PTE modification, nobody cares
      * about TLB flushes either.
      *
      * This very much relies on users (mm_tlb_flush_pending() and
      * mm_tlb_flush_nested()) only caring about _specific_ PTEs (and
      * therefore specific PTLs), because with SPLIT_PTE_PTLOCKS and RCpc
      * locks (PPC) the unlock of one doesn't order against the lock of
      * another PTL.
      *
      * The decrement is ordered by the flush_tlb_range(), such that
      * mm_tlb_flush_pending() will not return false unless all flushes have
      * completed.
      */
 }
 
 static inline void dec_tlb_flush_pending(struct mm_struct *mm)
 {
     /*
      * See inc_tlb_flush_pending().
      *
      * This cannot be smp_mb__before_atomic() because smp_mb() simply does
      * not order against TLB invalidate completion, which is what we need.
      *
      * Therefore we must rely on tlb_flush_*() to guarantee order.
      */
     atomic_dec(&mm->tlb_flush_pending);
 }
 
 static inline bool mm_tlb_flush_pending(struct mm_struct *mm)
 {
     /*
      * Must be called after having acquired the PTL; orders against that
      * PTLs release and therefore ensures that if we observe the modified
      * PTE we must also observe the increment from inc_tlb_flush_pending().
      *
      * That is, it only guarantees to return true if there is a flush
      * pending for _this_ PTL.
      */
     return atomic_read(&mm->tlb_flush_pending);
 }
 
 static inline bool mm_tlb_flush_nested(struct mm_struct *mm)
 {
     /*
      * Similar to mm_tlb_flush_pending(), we must have acquired the PTL
      * for which there is a TLB flush pending in order to guarantee
      * we've seen both that PTE modification and the increment.
      *
      * (no requirement on actually still holding the PTL, that is irrelevant)
      */
     return atomic_read(&mm->tlb_flush_pending) > 1;
 }
 
 /*
  * If this pte is wr-protected by uffd-wp in any form, arm the special pte to
  * replace a none pte.  NOTE!  This should only be called when *pte is already
  * cleared so we will never accidentally replace something valuable.  Meanwhile
  * none pte also means we are not demoting the pte so tlb flushed is not needed.
  * E.g., when pte cleared the caller should have taken care of the tlb flush.
  *
  * Must be called with pgtable lock held so that no thread will see the none
  * pte, and if they see it, they'll fault and serialize at the pgtable lock.
  *
  * This function is a no-op if PTE_MARKER_UFFD_WP is not enabled.
  */
 static inline void
 pte_install_uffd_wp_if_needed(struct vm_area_struct *vma, unsigned long addr,
                   pte_t *pte, pte_t pteval)
 {
 #ifdef CONFIG_PTE_MARKER_UFFD_WP
     bool arm_uffd_pte = false;
 
     /* The current status of the pte should be "cleared" before calling */
     WARN_ON_ONCE(!pte_none(*pte));
 
     if (vma_is_anonymous(vma) || !userfaultfd_wp(vma))
         return;
 
     /* A uffd-wp wr-protected normal pte */
     if (unlikely(pte_present(pteval) && pte_uffd_wp(pteval)))
         arm_uffd_pte = true;
 
     /*
      * A uffd-wp wr-protected swap pte.  Note: this should even cover an
      * existing pte marker with uffd-wp bit set.
      */
     if (unlikely(pte_swp_uffd_wp_any(pteval)))
         arm_uffd_pte = true;
 
     if (unlikely(arm_uffd_pte))
         set_pte_at(vma->vm_mm, addr, pte,
                make_pte_marker(PTE_MARKER_UFFD_WP));
 #endif
 }
 
 #endif

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