diff options
Diffstat (limited to 'include/linux/mm.h')
| -rw-r--r-- | include/linux/mm.h | 417 |
1 files changed, 168 insertions, 249 deletions
diff --git a/include/linux/mm.h b/include/linux/mm.h index bf55206935c4..9e221ffcb868 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -12,6 +12,7 @@ #include <linux/rbtree.h> #include <linux/atomic.h> #include <linux/debug_locks.h> +#include <linux/compiler.h> #include <linux/mm_types.h> #include <linux/mmap_lock.h> #include <linux/range.h> @@ -356,9 +357,7 @@ extern unsigned int kobjsize(const void *objp); # define VM_SHADOW_STACK VM_NONE #endif -#if defined(CONFIG_X86) -# define VM_PAT VM_ARCH_1 /* PAT reserves whole VMA at once (x86) */ -#elif defined(CONFIG_PPC64) +#if defined(CONFIG_PPC64) # define VM_SAO VM_ARCH_1 /* Strong Access Ordering (powerpc) */ #elif defined(CONFIG_PARISC) # define VM_GROWSUP VM_ARCH_1 @@ -385,7 +384,7 @@ extern unsigned int kobjsize(const void *objp); #endif #ifdef CONFIG_HAVE_ARCH_USERFAULTFD_MINOR -# define VM_UFFD_MINOR_BIT 38 +# define VM_UFFD_MINOR_BIT 41 # define VM_UFFD_MINOR BIT(VM_UFFD_MINOR_BIT) /* UFFD minor faults */ #else /* !CONFIG_HAVE_ARCH_USERFAULTFD_MINOR */ # define VM_UFFD_MINOR VM_NONE @@ -670,204 +669,11 @@ static inline void vma_numab_state_init(struct vm_area_struct *vma) {} static inline void vma_numab_state_free(struct vm_area_struct *vma) {} #endif /* CONFIG_NUMA_BALANCING */ -#ifdef CONFIG_PER_VMA_LOCK -static inline void vma_lock_init(struct vm_area_struct *vma, bool reset_refcnt) -{ -#ifdef CONFIG_DEBUG_LOCK_ALLOC - static struct lock_class_key lockdep_key; - - lockdep_init_map(&vma->vmlock_dep_map, "vm_lock", &lockdep_key, 0); -#endif - if (reset_refcnt) - refcount_set(&vma->vm_refcnt, 0); - vma->vm_lock_seq = UINT_MAX; -} - -static inline bool is_vma_writer_only(int refcnt) -{ - /* - * With a writer and no readers, refcnt is VMA_LOCK_OFFSET if the vma - * is detached and (VMA_LOCK_OFFSET + 1) if it is attached. Waiting on - * a detached vma happens only in vma_mark_detached() and is a rare - * case, therefore most of the time there will be no unnecessary wakeup. - */ - return refcnt & VMA_LOCK_OFFSET && refcnt <= VMA_LOCK_OFFSET + 1; -} - -static inline void vma_refcount_put(struct vm_area_struct *vma) -{ - /* Use a copy of vm_mm in case vma is freed after we drop vm_refcnt */ - struct mm_struct *mm = vma->vm_mm; - int oldcnt; - - rwsem_release(&vma->vmlock_dep_map, _RET_IP_); - if (!__refcount_dec_and_test(&vma->vm_refcnt, &oldcnt)) { - - if (is_vma_writer_only(oldcnt - 1)) - rcuwait_wake_up(&mm->vma_writer_wait); - } -} - /* - * Try to read-lock a vma. The function is allowed to occasionally yield false - * locked result to avoid performance overhead, in which case we fall back to - * using mmap_lock. The function should never yield false unlocked result. - * False locked result is possible if mm_lock_seq overflows or if vma gets - * reused and attached to a different mm before we lock it. - * Returns the vma on success, NULL on failure to lock and EAGAIN if vma got - * detached. + * These must be here rather than mmap_lock.h as dependent on vm_fault type, + * declared in this header. */ -static inline struct vm_area_struct *vma_start_read(struct mm_struct *mm, - struct vm_area_struct *vma) -{ - int oldcnt; - - /* - * Check before locking. A race might cause false locked result. - * We can use READ_ONCE() for the mm_lock_seq here, and don't need - * ACQUIRE semantics, because this is just a lockless check whose result - * we don't rely on for anything - the mm_lock_seq read against which we - * need ordering is below. - */ - if (READ_ONCE(vma->vm_lock_seq) == READ_ONCE(mm->mm_lock_seq.sequence)) - return NULL; - - /* - * If VMA_LOCK_OFFSET is set, __refcount_inc_not_zero_limited_acquire() - * will fail because VMA_REF_LIMIT is less than VMA_LOCK_OFFSET. - * Acquire fence is required here to avoid reordering against later - * vm_lock_seq check and checks inside lock_vma_under_rcu(). - */ - if (unlikely(!__refcount_inc_not_zero_limited_acquire(&vma->vm_refcnt, &oldcnt, - VMA_REF_LIMIT))) { - /* return EAGAIN if vma got detached from under us */ - return oldcnt ? NULL : ERR_PTR(-EAGAIN); - } - - rwsem_acquire_read(&vma->vmlock_dep_map, 0, 1, _RET_IP_); - /* - * Overflow of vm_lock_seq/mm_lock_seq might produce false locked result. - * False unlocked result is impossible because we modify and check - * vma->vm_lock_seq under vma->vm_refcnt protection and mm->mm_lock_seq - * modification invalidates all existing locks. - * - * We must use ACQUIRE semantics for the mm_lock_seq so that if we are - * racing with vma_end_write_all(), we only start reading from the VMA - * after it has been unlocked. - * This pairs with RELEASE semantics in vma_end_write_all(). - */ - if (unlikely(vma->vm_lock_seq == raw_read_seqcount(&mm->mm_lock_seq))) { - vma_refcount_put(vma); - return NULL; - } - - return vma; -} - -/* - * Use only while holding mmap read lock which guarantees that locking will not - * fail (nobody can concurrently write-lock the vma). vma_start_read() should - * not be used in such cases because it might fail due to mm_lock_seq overflow. - * This functionality is used to obtain vma read lock and drop the mmap read lock. - */ -static inline bool vma_start_read_locked_nested(struct vm_area_struct *vma, int subclass) -{ - int oldcnt; - - mmap_assert_locked(vma->vm_mm); - if (unlikely(!__refcount_inc_not_zero_limited_acquire(&vma->vm_refcnt, &oldcnt, - VMA_REF_LIMIT))) - return false; - - rwsem_acquire_read(&vma->vmlock_dep_map, 0, 1, _RET_IP_); - return true; -} - -/* - * Use only while holding mmap read lock which guarantees that locking will not - * fail (nobody can concurrently write-lock the vma). vma_start_read() should - * not be used in such cases because it might fail due to mm_lock_seq overflow. - * This functionality is used to obtain vma read lock and drop the mmap read lock. - */ -static inline bool vma_start_read_locked(struct vm_area_struct *vma) -{ - return vma_start_read_locked_nested(vma, 0); -} - -static inline void vma_end_read(struct vm_area_struct *vma) -{ - vma_refcount_put(vma); -} - -/* WARNING! Can only be used if mmap_lock is expected to be write-locked */ -static bool __is_vma_write_locked(struct vm_area_struct *vma, unsigned int *mm_lock_seq) -{ - mmap_assert_write_locked(vma->vm_mm); - - /* - * current task is holding mmap_write_lock, both vma->vm_lock_seq and - * mm->mm_lock_seq can't be concurrently modified. - */ - *mm_lock_seq = vma->vm_mm->mm_lock_seq.sequence; - return (vma->vm_lock_seq == *mm_lock_seq); -} - -void __vma_start_write(struct vm_area_struct *vma, unsigned int mm_lock_seq); - -/* - * Begin writing to a VMA. - * Exclude concurrent readers under the per-VMA lock until the currently - * write-locked mmap_lock is dropped or downgraded. - */ -static inline void vma_start_write(struct vm_area_struct *vma) -{ - unsigned int mm_lock_seq; - - if (__is_vma_write_locked(vma, &mm_lock_seq)) - return; - - __vma_start_write(vma, mm_lock_seq); -} - -static inline void vma_assert_write_locked(struct vm_area_struct *vma) -{ - unsigned int mm_lock_seq; - - VM_BUG_ON_VMA(!__is_vma_write_locked(vma, &mm_lock_seq), vma); -} - -static inline void vma_assert_locked(struct vm_area_struct *vma) -{ - unsigned int mm_lock_seq; - - VM_BUG_ON_VMA(refcount_read(&vma->vm_refcnt) <= 1 && - !__is_vma_write_locked(vma, &mm_lock_seq), vma); -} - -/* - * WARNING: to avoid racing with vma_mark_attached()/vma_mark_detached(), these - * assertions should be made either under mmap_write_lock or when the object - * has been isolated under mmap_write_lock, ensuring no competing writers. - */ -static inline void vma_assert_attached(struct vm_area_struct *vma) -{ - WARN_ON_ONCE(!refcount_read(&vma->vm_refcnt)); -} - -static inline void vma_assert_detached(struct vm_area_struct *vma) -{ - WARN_ON_ONCE(refcount_read(&vma->vm_refcnt)); -} - -static inline void vma_mark_attached(struct vm_area_struct *vma) -{ - vma_assert_write_locked(vma); - vma_assert_detached(vma); - refcount_set_release(&vma->vm_refcnt, 1); -} - -void vma_mark_detached(struct vm_area_struct *vma); - +#ifdef CONFIG_PER_VMA_LOCK static inline void release_fault_lock(struct vm_fault *vmf) { if (vmf->flags & FAULT_FLAG_VMA_LOCK) @@ -883,36 +689,7 @@ static inline void assert_fault_locked(struct vm_fault *vmf) else mmap_assert_locked(vmf->vma->vm_mm); } - -struct vm_area_struct *lock_vma_under_rcu(struct mm_struct *mm, - unsigned long address); - -#else /* CONFIG_PER_VMA_LOCK */ - -static inline void vma_lock_init(struct vm_area_struct *vma, bool reset_refcnt) {} -static inline struct vm_area_struct *vma_start_read(struct mm_struct *mm, - struct vm_area_struct *vma) - { return NULL; } -static inline void vma_end_read(struct vm_area_struct *vma) {} -static inline void vma_start_write(struct vm_area_struct *vma) {} -static inline void vma_assert_write_locked(struct vm_area_struct *vma) - { mmap_assert_write_locked(vma->vm_mm); } -static inline void vma_assert_attached(struct vm_area_struct *vma) {} -static inline void vma_assert_detached(struct vm_area_struct *vma) {} -static inline void vma_mark_attached(struct vm_area_struct *vma) {} -static inline void vma_mark_detached(struct vm_area_struct *vma) {} - -static inline struct vm_area_struct *lock_vma_under_rcu(struct mm_struct *mm, - unsigned long address) -{ - return NULL; -} - -static inline void vma_assert_locked(struct vm_area_struct *vma) -{ - mmap_assert_locked(vma->vm_mm); -} - +#else static inline void release_fault_lock(struct vm_fault *vmf) { mmap_read_unlock(vmf->vma->vm_mm); @@ -922,7 +699,6 @@ static inline void assert_fault_locked(struct vm_fault *vmf) { mmap_assert_locked(vmf->vma->vm_mm); } - #endif /* CONFIG_PER_VMA_LOCK */ extern const struct vm_operations_struct vma_dummy_vm_ops; @@ -1459,7 +1235,7 @@ static inline pte_t maybe_mkwrite(pte_t pte, struct vm_area_struct *vma) return pte; } -vm_fault_t do_set_pmd(struct vm_fault *vmf, struct page *page); +vm_fault_t do_set_pmd(struct vm_fault *vmf, struct folio *folio, struct page *page); void set_pte_range(struct vm_fault *vmf, struct folio *folio, struct page *page, unsigned int nr, unsigned long addr); @@ -2004,6 +1780,45 @@ static inline struct folio *pfn_folio(unsigned long pfn) return page_folio(pfn_to_page(pfn)); } +#ifdef CONFIG_MMU +static inline pte_t mk_pte(struct page *page, pgprot_t pgprot) +{ + return pfn_pte(page_to_pfn(page), pgprot); +} + +/** + * folio_mk_pte - Create a PTE for this folio + * @folio: The folio to create a PTE for + * @pgprot: The page protection bits to use + * + * Create a page table entry for the first page of this folio. + * This is suitable for passing to set_ptes(). + * + * Return: A page table entry suitable for mapping this folio. + */ +static inline pte_t folio_mk_pte(struct folio *folio, pgprot_t pgprot) +{ + return pfn_pte(folio_pfn(folio), pgprot); +} + +#ifdef CONFIG_TRANSPARENT_HUGEPAGE +/** + * folio_mk_pmd - Create a PMD for this folio + * @folio: The folio to create a PMD for + * @pgprot: The page protection bits to use + * + * Create a page table entry for the first page of this folio. + * This is suitable for passing to set_pmd_at(). + * + * Return: A page table entry suitable for mapping this folio. + */ +static inline pmd_t folio_mk_pmd(struct folio *folio, pgprot_t pgprot) +{ + return pmd_mkhuge(pfn_pmd(folio_pfn(folio), pgprot)); +} +#endif +#endif /* CONFIG_MMU */ + static inline bool folio_has_pincount(const struct folio *folio) { if (IS_ENABLED(CONFIG_64BIT)) @@ -2185,15 +2000,6 @@ static inline long compound_nr(struct page *page) } /** - * thp_nr_pages - The number of regular pages in this huge page. - * @page: The head page of a huge page. - */ -static inline long thp_nr_pages(struct page *page) -{ - return folio_nr_pages((struct folio *)page); -} - -/** * folio_next - Move to the next physical folio. * @folio: The folio we're currently operating on. * @@ -2303,7 +2109,62 @@ static inline bool folio_maybe_mapped_shared(struct folio *folio) */ if (mapcount <= 1) return false; - return folio_test_large_maybe_mapped_shared(folio); + return test_bit(FOLIO_MM_IDS_SHARED_BITNUM, &folio->_mm_ids); +} + +/** + * folio_expected_ref_count - calculate the expected folio refcount + * @folio: the folio + * + * Calculate the expected folio refcount, taking references from the pagecache, + * swapcache, PG_private and page table mappings into account. Useful in + * combination with folio_ref_count() to detect unexpected references (e.g., + * GUP or other temporary references). + * + * Does currently not consider references from the LRU cache. If the folio + * was isolated from the LRU (which is the case during migration or split), + * the LRU cache does not apply. + * + * Calling this function on an unmapped folio -- !folio_mapped() -- that is + * locked will return a stable result. + * + * Calling this function on a mapped folio will not result in a stable result, + * because nothing stops additional page table mappings from coming (e.g., + * fork()) or going (e.g., munmap()). + * + * Calling this function without the folio lock will also not result in a + * stable result: for example, the folio might get dropped from the swapcache + * concurrently. + * + * However, even when called without the folio lock or on a mapped folio, + * this function can be used to detect unexpected references early (for example, + * if it makes sense to even lock the folio and unmap it). + * + * The caller must add any reference (e.g., from folio_try_get()) it might be + * holding itself to the result. + * + * Returns the expected folio refcount. + */ +static inline int folio_expected_ref_count(const struct folio *folio) +{ + const int order = folio_order(folio); + int ref_count = 0; + + if (WARN_ON_ONCE(folio_test_slab(folio))) + return 0; + + if (folio_test_anon(folio)) { + /* One reference per page from the swapcache. */ + ref_count += folio_test_swapcache(folio) << order; + } else if (!((unsigned long)folio->mapping & PAGE_MAPPING_FLAGS)) { + /* One reference per page from the pagecache. */ + ref_count += !!folio->mapping << order; + /* One reference from PG_private. */ + ref_count += folio_test_private(folio); + } + + /* One reference per page table mapping. */ + return ref_count + folio_mapcount(folio); } #ifndef HAVE_ARCH_MAKE_FOLIO_ACCESSIBLE @@ -2406,7 +2267,6 @@ static inline void clear_page_pfmemalloc(struct page *page) extern void pagefault_out_of_memory(void); #define offset_in_page(p) ((unsigned long)(p) & ~PAGE_MASK) -#define offset_in_thp(page, p) ((unsigned long)(p) & (thp_size(page) - 1)) #define offset_in_folio(folio, p) ((unsigned long)(p) & (folio_size(folio) - 1)) /* @@ -2767,7 +2627,7 @@ static inline void update_hiwater_rss(struct mm_struct *mm) { unsigned long _rss = get_mm_rss(mm); - if ((mm)->hiwater_rss < _rss) + if (data_race(mm->hiwater_rss) < _rss) (mm)->hiwater_rss = _rss; } @@ -3117,9 +2977,10 @@ static inline void pagetable_dtor_free(struct ptdesc *ptdesc) pagetable_free(ptdesc); } -static inline bool pagetable_pte_ctor(struct ptdesc *ptdesc) +static inline bool pagetable_pte_ctor(struct mm_struct *mm, + struct ptdesc *ptdesc) { - if (!ptlock_init(ptdesc)) + if (mm != &init_mm && !ptlock_init(ptdesc)) return false; __pagetable_ctor(ptdesc); return true; @@ -3223,9 +3084,10 @@ static inline spinlock_t *pmd_lock(struct mm_struct *mm, pmd_t *pmd) return ptl; } -static inline bool pagetable_pmd_ctor(struct ptdesc *ptdesc) +static inline bool pagetable_pmd_ctor(struct mm_struct *mm, + struct ptdesc *ptdesc) { - if (!pmd_ptlock_init(ptdesc)) + if (mm != &init_mm && !pmd_ptlock_init(ptdesc)) return false; ptdesc_pmd_pts_init(ptdesc); __pagetable_ctor(ptdesc); @@ -3414,7 +3276,6 @@ void anon_vma_interval_tree_verify(struct anon_vma_chain *node); extern int __vm_enough_memory(struct mm_struct *mm, long pages, int cap_sys_admin); extern int insert_vm_struct(struct mm_struct *, struct vm_area_struct *); extern void exit_mmap(struct mm_struct *); -int relocate_vma_down(struct vm_area_struct *vma, unsigned long shift); bool mmap_read_lock_maybe_expand(struct mm_struct *mm, struct vm_area_struct *vma, unsigned long addr, bool write); @@ -4265,4 +4126,62 @@ int arch_lock_shadow_stack_status(struct task_struct *t, unsigned long status); #define VM_SEALED_SYSMAP VM_NONE #endif +/* + * DMA mapping IDs for page_pool + * + * When DMA-mapping a page, page_pool allocates an ID (from an xarray) and + * stashes it in the upper bits of page->pp_magic. We always want to be able to + * unambiguously identify page pool pages (using page_pool_page_is_pp()). Non-PP + * pages can have arbitrary kernel pointers stored in the same field as pp_magic + * (since it overlaps with page->lru.next), so we must ensure that we cannot + * mistake a valid kernel pointer with any of the values we write into this + * field. + * + * On architectures that set POISON_POINTER_DELTA, this is already ensured, + * since this value becomes part of PP_SIGNATURE; meaning we can just use the + * space between the PP_SIGNATURE value (without POISON_POINTER_DELTA), and the + * lowest bits of POISON_POINTER_DELTA. On arches where POISON_POINTER_DELTA is + * 0, we make sure that we leave the two topmost bits empty, as that guarantees + * we won't mistake a valid kernel pointer for a value we set, regardless of the + * VMSPLIT setting. + * + * Altogether, this means that the number of bits available is constrained by + * the size of an unsigned long (at the upper end, subtracting two bits per the + * above), and the definition of PP_SIGNATURE (with or without + * POISON_POINTER_DELTA). + */ +#define PP_DMA_INDEX_SHIFT (1 + __fls(PP_SIGNATURE - POISON_POINTER_DELTA)) +#if POISON_POINTER_DELTA > 0 +/* PP_SIGNATURE includes POISON_POINTER_DELTA, so limit the size of the DMA + * index to not overlap with that if set + */ +#define PP_DMA_INDEX_BITS MIN(32, __ffs(POISON_POINTER_DELTA) - PP_DMA_INDEX_SHIFT) +#else +/* Always leave out the topmost two; see above. */ +#define PP_DMA_INDEX_BITS MIN(32, BITS_PER_LONG - PP_DMA_INDEX_SHIFT - 2) +#endif + +#define PP_DMA_INDEX_MASK GENMASK(PP_DMA_INDEX_BITS + PP_DMA_INDEX_SHIFT - 1, \ + PP_DMA_INDEX_SHIFT) + +/* Mask used for checking in page_pool_page_is_pp() below. page->pp_magic is + * OR'ed with PP_SIGNATURE after the allocation in order to preserve bit 0 for + * the head page of compound page and bit 1 for pfmemalloc page, as well as the + * bits used for the DMA index. page_is_pfmemalloc() is checked in + * __page_pool_put_page() to avoid recycling the pfmemalloc page. + */ +#define PP_MAGIC_MASK ~(PP_DMA_INDEX_MASK | 0x3UL) + +#ifdef CONFIG_PAGE_POOL +static inline bool page_pool_page_is_pp(struct page *page) +{ + return (page->pp_magic & PP_MAGIC_MASK) == PP_SIGNATURE; +} +#else +static inline bool page_pool_page_is_pp(struct page *page) +{ + return false; +} +#endif + #endif /* _LINUX_MM_H */ |