mm_inline.h (10593B)
1/* SPDX-License-Identifier: GPL-2.0 */ 2#ifndef LINUX_MM_INLINE_H 3#define LINUX_MM_INLINE_H 4 5#include <linux/atomic.h> 6#include <linux/huge_mm.h> 7#include <linux/swap.h> 8#include <linux/string.h> 9#include <linux/userfaultfd_k.h> 10#include <linux/swapops.h> 11 12/** 13 * folio_is_file_lru - Should the folio be on a file LRU or anon LRU? 14 * @folio: The folio to test. 15 * 16 * We would like to get this info without a page flag, but the state 17 * needs to survive until the folio is last deleted from the LRU, which 18 * could be as far down as __page_cache_release. 19 * 20 * Return: An integer (not a boolean!) used to sort a folio onto the 21 * right LRU list and to account folios correctly. 22 * 1 if @folio is a regular filesystem backed page cache folio 23 * or a lazily freed anonymous folio (e.g. via MADV_FREE). 24 * 0 if @folio is a normal anonymous folio, a tmpfs folio or otherwise 25 * ram or swap backed folio. 26 */ 27static inline int folio_is_file_lru(struct folio *folio) 28{ 29 return !folio_test_swapbacked(folio); 30} 31 32static inline int page_is_file_lru(struct page *page) 33{ 34 return folio_is_file_lru(page_folio(page)); 35} 36 37static __always_inline void update_lru_size(struct lruvec *lruvec, 38 enum lru_list lru, enum zone_type zid, 39 long nr_pages) 40{ 41 struct pglist_data *pgdat = lruvec_pgdat(lruvec); 42 43 __mod_lruvec_state(lruvec, NR_LRU_BASE + lru, nr_pages); 44 __mod_zone_page_state(&pgdat->node_zones[zid], 45 NR_ZONE_LRU_BASE + lru, nr_pages); 46#ifdef CONFIG_MEMCG 47 mem_cgroup_update_lru_size(lruvec, lru, zid, nr_pages); 48#endif 49} 50 51/** 52 * __folio_clear_lru_flags - Clear page lru flags before releasing a page. 53 * @folio: The folio that was on lru and now has a zero reference. 54 */ 55static __always_inline void __folio_clear_lru_flags(struct folio *folio) 56{ 57 VM_BUG_ON_FOLIO(!folio_test_lru(folio), folio); 58 59 __folio_clear_lru(folio); 60 61 /* this shouldn't happen, so leave the flags to bad_page() */ 62 if (folio_test_active(folio) && folio_test_unevictable(folio)) 63 return; 64 65 __folio_clear_active(folio); 66 __folio_clear_unevictable(folio); 67} 68 69static __always_inline void __clear_page_lru_flags(struct page *page) 70{ 71 __folio_clear_lru_flags(page_folio(page)); 72} 73 74/** 75 * folio_lru_list - Which LRU list should a folio be on? 76 * @folio: The folio to test. 77 * 78 * Return: The LRU list a folio should be on, as an index 79 * into the array of LRU lists. 80 */ 81static __always_inline enum lru_list folio_lru_list(struct folio *folio) 82{ 83 enum lru_list lru; 84 85 VM_BUG_ON_FOLIO(folio_test_active(folio) && folio_test_unevictable(folio), folio); 86 87 if (folio_test_unevictable(folio)) 88 return LRU_UNEVICTABLE; 89 90 lru = folio_is_file_lru(folio) ? LRU_INACTIVE_FILE : LRU_INACTIVE_ANON; 91 if (folio_test_active(folio)) 92 lru += LRU_ACTIVE; 93 94 return lru; 95} 96 97static __always_inline 98void lruvec_add_folio(struct lruvec *lruvec, struct folio *folio) 99{ 100 enum lru_list lru = folio_lru_list(folio); 101 102 update_lru_size(lruvec, lru, folio_zonenum(folio), 103 folio_nr_pages(folio)); 104 if (lru != LRU_UNEVICTABLE) 105 list_add(&folio->lru, &lruvec->lists[lru]); 106} 107 108static __always_inline void add_page_to_lru_list(struct page *page, 109 struct lruvec *lruvec) 110{ 111 lruvec_add_folio(lruvec, page_folio(page)); 112} 113 114static __always_inline 115void lruvec_add_folio_tail(struct lruvec *lruvec, struct folio *folio) 116{ 117 enum lru_list lru = folio_lru_list(folio); 118 119 update_lru_size(lruvec, lru, folio_zonenum(folio), 120 folio_nr_pages(folio)); 121 /* This is not expected to be used on LRU_UNEVICTABLE */ 122 list_add_tail(&folio->lru, &lruvec->lists[lru]); 123} 124 125static __always_inline void add_page_to_lru_list_tail(struct page *page, 126 struct lruvec *lruvec) 127{ 128 lruvec_add_folio_tail(lruvec, page_folio(page)); 129} 130 131static __always_inline 132void lruvec_del_folio(struct lruvec *lruvec, struct folio *folio) 133{ 134 enum lru_list lru = folio_lru_list(folio); 135 136 if (lru != LRU_UNEVICTABLE) 137 list_del(&folio->lru); 138 update_lru_size(lruvec, lru, folio_zonenum(folio), 139 -folio_nr_pages(folio)); 140} 141 142static __always_inline void del_page_from_lru_list(struct page *page, 143 struct lruvec *lruvec) 144{ 145 lruvec_del_folio(lruvec, page_folio(page)); 146} 147 148#ifdef CONFIG_ANON_VMA_NAME 149/* 150 * mmap_lock should be read-locked when calling anon_vma_name(). Caller should 151 * either keep holding the lock while using the returned pointer or it should 152 * raise anon_vma_name refcount before releasing the lock. 153 */ 154extern struct anon_vma_name *anon_vma_name(struct vm_area_struct *vma); 155extern struct anon_vma_name *anon_vma_name_alloc(const char *name); 156extern void anon_vma_name_free(struct kref *kref); 157 158/* mmap_lock should be read-locked */ 159static inline void anon_vma_name_get(struct anon_vma_name *anon_name) 160{ 161 if (anon_name) 162 kref_get(&anon_name->kref); 163} 164 165static inline void anon_vma_name_put(struct anon_vma_name *anon_name) 166{ 167 if (anon_name) 168 kref_put(&anon_name->kref, anon_vma_name_free); 169} 170 171static inline 172struct anon_vma_name *anon_vma_name_reuse(struct anon_vma_name *anon_name) 173{ 174 /* Prevent anon_name refcount saturation early on */ 175 if (kref_read(&anon_name->kref) < REFCOUNT_MAX) { 176 anon_vma_name_get(anon_name); 177 return anon_name; 178 179 } 180 return anon_vma_name_alloc(anon_name->name); 181} 182 183static inline void dup_anon_vma_name(struct vm_area_struct *orig_vma, 184 struct vm_area_struct *new_vma) 185{ 186 struct anon_vma_name *anon_name = anon_vma_name(orig_vma); 187 188 if (anon_name) 189 new_vma->anon_name = anon_vma_name_reuse(anon_name); 190} 191 192static inline void free_anon_vma_name(struct vm_area_struct *vma) 193{ 194 /* 195 * Not using anon_vma_name because it generates a warning if mmap_lock 196 * is not held, which might be the case here. 197 */ 198 if (!vma->vm_file) 199 anon_vma_name_put(vma->anon_name); 200} 201 202static inline bool anon_vma_name_eq(struct anon_vma_name *anon_name1, 203 struct anon_vma_name *anon_name2) 204{ 205 if (anon_name1 == anon_name2) 206 return true; 207 208 return anon_name1 && anon_name2 && 209 !strcmp(anon_name1->name, anon_name2->name); 210} 211 212#else /* CONFIG_ANON_VMA_NAME */ 213static inline struct anon_vma_name *anon_vma_name(struct vm_area_struct *vma) 214{ 215 return NULL; 216} 217 218static inline struct anon_vma_name *anon_vma_name_alloc(const char *name) 219{ 220 return NULL; 221} 222 223static inline void anon_vma_name_get(struct anon_vma_name *anon_name) {} 224static inline void anon_vma_name_put(struct anon_vma_name *anon_name) {} 225static inline void dup_anon_vma_name(struct vm_area_struct *orig_vma, 226 struct vm_area_struct *new_vma) {} 227static inline void free_anon_vma_name(struct vm_area_struct *vma) {} 228 229static inline bool anon_vma_name_eq(struct anon_vma_name *anon_name1, 230 struct anon_vma_name *anon_name2) 231{ 232 return true; 233} 234 235#endif /* CONFIG_ANON_VMA_NAME */ 236 237static inline void init_tlb_flush_pending(struct mm_struct *mm) 238{ 239 atomic_set(&mm->tlb_flush_pending, 0); 240} 241 242static inline void inc_tlb_flush_pending(struct mm_struct *mm) 243{ 244 atomic_inc(&mm->tlb_flush_pending); 245 /* 246 * The only time this value is relevant is when there are indeed pages 247 * to flush. And we'll only flush pages after changing them, which 248 * requires the PTL. 249 * 250 * So the ordering here is: 251 * 252 * atomic_inc(&mm->tlb_flush_pending); 253 * spin_lock(&ptl); 254 * ... 255 * set_pte_at(); 256 * spin_unlock(&ptl); 257 * 258 * spin_lock(&ptl) 259 * mm_tlb_flush_pending(); 260 * .... 261 * spin_unlock(&ptl); 262 * 263 * flush_tlb_range(); 264 * atomic_dec(&mm->tlb_flush_pending); 265 * 266 * Where the increment if constrained by the PTL unlock, it thus 267 * ensures that the increment is visible if the PTE modification is 268 * visible. After all, if there is no PTE modification, nobody cares 269 * about TLB flushes either. 270 * 271 * This very much relies on users (mm_tlb_flush_pending() and 272 * mm_tlb_flush_nested()) only caring about _specific_ PTEs (and 273 * therefore specific PTLs), because with SPLIT_PTE_PTLOCKS and RCpc 274 * locks (PPC) the unlock of one doesn't order against the lock of 275 * another PTL. 276 * 277 * The decrement is ordered by the flush_tlb_range(), such that 278 * mm_tlb_flush_pending() will not return false unless all flushes have 279 * completed. 280 */ 281} 282 283static inline void dec_tlb_flush_pending(struct mm_struct *mm) 284{ 285 /* 286 * See inc_tlb_flush_pending(). 287 * 288 * This cannot be smp_mb__before_atomic() because smp_mb() simply does 289 * not order against TLB invalidate completion, which is what we need. 290 * 291 * Therefore we must rely on tlb_flush_*() to guarantee order. 292 */ 293 atomic_dec(&mm->tlb_flush_pending); 294} 295 296static inline bool mm_tlb_flush_pending(struct mm_struct *mm) 297{ 298 /* 299 * Must be called after having acquired the PTL; orders against that 300 * PTLs release and therefore ensures that if we observe the modified 301 * PTE we must also observe the increment from inc_tlb_flush_pending(). 302 * 303 * That is, it only guarantees to return true if there is a flush 304 * pending for _this_ PTL. 305 */ 306 return atomic_read(&mm->tlb_flush_pending); 307} 308 309static inline bool mm_tlb_flush_nested(struct mm_struct *mm) 310{ 311 /* 312 * Similar to mm_tlb_flush_pending(), we must have acquired the PTL 313 * for which there is a TLB flush pending in order to guarantee 314 * we've seen both that PTE modification and the increment. 315 * 316 * (no requirement on actually still holding the PTL, that is irrelevant) 317 */ 318 return atomic_read(&mm->tlb_flush_pending) > 1; 319} 320 321/* 322 * If this pte is wr-protected by uffd-wp in any form, arm the special pte to 323 * replace a none pte. NOTE! This should only be called when *pte is already 324 * cleared so we will never accidentally replace something valuable. Meanwhile 325 * none pte also means we are not demoting the pte so tlb flushed is not needed. 326 * E.g., when pte cleared the caller should have taken care of the tlb flush. 327 * 328 * Must be called with pgtable lock held so that no thread will see the none 329 * pte, and if they see it, they'll fault and serialize at the pgtable lock. 330 * 331 * This function is a no-op if PTE_MARKER_UFFD_WP is not enabled. 332 */ 333static inline void 334pte_install_uffd_wp_if_needed(struct vm_area_struct *vma, unsigned long addr, 335 pte_t *pte, pte_t pteval) 336{ 337#ifdef CONFIG_PTE_MARKER_UFFD_WP 338 bool arm_uffd_pte = false; 339 340 /* The current status of the pte should be "cleared" before calling */ 341 WARN_ON_ONCE(!pte_none(*pte)); 342 343 if (vma_is_anonymous(vma) || !userfaultfd_wp(vma)) 344 return; 345 346 /* A uffd-wp wr-protected normal pte */ 347 if (unlikely(pte_present(pteval) && pte_uffd_wp(pteval))) 348 arm_uffd_pte = true; 349 350 /* 351 * A uffd-wp wr-protected swap pte. Note: this should even cover an 352 * existing pte marker with uffd-wp bit set. 353 */ 354 if (unlikely(pte_swp_uffd_wp_any(pteval))) 355 arm_uffd_pte = true; 356 357 if (unlikely(arm_uffd_pte)) 358 set_pte_at(vma->vm_mm, addr, pte, 359 make_pte_marker(PTE_MARKER_UFFD_WP)); 360#endif 361} 362 363#endif