1 /* SPDX-License-Identifier: GPL-2.0 */ 2 #ifndef _LINUX_MM_TYPES_H 3 #define _LINUX_MM_TYPES_H 4 5 #include <linux/mm_types_task.h> 6 7 #include <linux/auxvec.h> 8 #include <linux/kref.h> 9 #include <linux/list.h> 10 #include <linux/spinlock.h> 11 #include <linux/rbtree.h> 12 #include <linux/maple_tree.h> 13 #include <linux/rwsem.h> 14 #include <linux/completion.h> 15 #include <linux/cpumask.h> 16 #include <linux/uprobes.h> 17 #include <linux/rcupdate.h> 18 #include <linux/page-flags-layout.h> 19 #include <linux/workqueue.h> 20 #include <linux/seqlock.h> 21 #include <linux/percpu_counter.h> 22 23 #include <asm/mmu.h> 24 25 #ifndef AT_VECTOR_SIZE_ARCH 26 #define AT_VECTOR_SIZE_ARCH 0 27 #endif 28 #define AT_VECTOR_SIZE (2*(AT_VECTOR_SIZE_ARCH + AT_VECTOR_SIZE_BASE + 1)) 29 30 #define INIT_PASID 0 31 32 struct address_space; 33 struct mem_cgroup; 34 35 /* 36 * Each physical page in the system has a struct page associated with 37 * it to keep track of whatever it is we are using the page for at the 38 * moment. Note that we have no way to track which tasks are using 39 * a page, though if it is a pagecache page, rmap structures can tell us 40 * who is mapping it. 41 * 42 * If you allocate the page using alloc_pages(), you can use some of the 43 * space in struct page for your own purposes. The five words in the main 44 * union are available, except for bit 0 of the first word which must be 45 * kept clear. Many users use this word to store a pointer to an object 46 * which is guaranteed to be aligned. If you use the same storage as 47 * page->mapping, you must restore it to NULL before freeing the page. 48 * 49 * If your page will not be mapped to userspace, you can also use the four 50 * bytes in the mapcount union, but you must call page_mapcount_reset() 51 * before freeing it. 52 * 53 * If you want to use the refcount field, it must be used in such a way 54 * that other CPUs temporarily incrementing and then decrementing the 55 * refcount does not cause problems. On receiving the page from 56 * alloc_pages(), the refcount will be positive. 57 * 58 * If you allocate pages of order > 0, you can use some of the fields 59 * in each subpage, but you may need to restore some of their values 60 * afterwards. 61 * 62 * SLUB uses cmpxchg_double() to atomically update its freelist and counters. 63 * That requires that freelist & counters in struct slab be adjacent and 64 * double-word aligned. Because struct slab currently just reinterprets the 65 * bits of struct page, we align all struct pages to double-word boundaries, 66 * and ensure that 'freelist' is aligned within struct slab. 67 */ 68 #ifdef CONFIG_HAVE_ALIGNED_STRUCT_PAGE 69 #define _struct_page_alignment __aligned(2 * sizeof(unsigned long)) 70 #else 71 #define _struct_page_alignment __aligned(sizeof(unsigned long)) 72 #endif 73 74 struct page { 75 unsigned long flags; /* Atomic flags, some possibly 76 * updated asynchronously */ 77 /* 78 * Five words (20/40 bytes) are available in this union. 79 * WARNING: bit 0 of the first word is used for PageTail(). That 80 * means the other users of this union MUST NOT use the bit to 81 * avoid collision and false-positive PageTail(). 82 */ 83 union { 84 struct { /* Page cache and anonymous pages */ 85 /** 86 * @lru: Pageout list, eg. active_list protected by 87 * lruvec->lru_lock. Sometimes used as a generic list 88 * by the page owner. 89 */ 90 union { 91 struct list_head lru; 92 93 /* Or, for the Unevictable "LRU list" slot */ 94 struct { 95 /* Always even, to negate PageTail */ 96 void *__filler; 97 /* Count page's or folio's mlocks */ 98 unsigned int mlock_count; 99 }; 100 101 /* Or, free page */ 102 struct list_head buddy_list; 103 struct list_head pcp_list; 104 }; 105 /* See page-flags.h for PAGE_MAPPING_FLAGS */ 106 struct address_space *mapping; 107 union { 108 pgoff_t index; /* Our offset within mapping. */ 109 unsigned long share; /* share count for fsdax */ 110 }; 111 /** 112 * @private: Mapping-private opaque data. 113 * Usually used for buffer_heads if PagePrivate. 114 * Used for swp_entry_t if PageSwapCache. 115 * Indicates order in the buddy system if PageBuddy. 116 */ 117 unsigned long private; 118 }; 119 struct { /* page_pool used by netstack */ 120 /** 121 * @pp_magic: magic value to avoid recycling non 122 * page_pool allocated pages. 123 */ 124 unsigned long pp_magic; 125 struct page_pool *pp; 126 unsigned long _pp_mapping_pad; 127 unsigned long dma_addr; 128 union { 129 /** 130 * dma_addr_upper: might require a 64-bit 131 * value on 32-bit architectures. 132 */ 133 unsigned long dma_addr_upper; 134 /** 135 * For frag page support, not supported in 136 * 32-bit architectures with 64-bit DMA. 137 */ 138 atomic_long_t pp_frag_count; 139 }; 140 }; 141 struct { /* Tail pages of compound page */ 142 unsigned long compound_head; /* Bit zero is set */ 143 }; 144 struct { /* Page table pages */ 145 unsigned long _pt_pad_1; /* compound_head */ 146 pgtable_t pmd_huge_pte; /* protected by page->ptl */ 147 unsigned long _pt_pad_2; /* mapping */ 148 union { 149 struct mm_struct *pt_mm; /* x86 pgds only */ 150 atomic_t pt_frag_refcount; /* powerpc */ 151 }; 152 #if ALLOC_SPLIT_PTLOCKS 153 spinlock_t *ptl; 154 #else 155 spinlock_t ptl; 156 #endif 157 }; 158 struct { /* ZONE_DEVICE pages */ 159 /** @pgmap: Points to the hosting device page map. */ 160 struct dev_pagemap *pgmap; 161 void *zone_device_data; 162 /* 163 * ZONE_DEVICE private pages are counted as being 164 * mapped so the next 3 words hold the mapping, index, 165 * and private fields from the source anonymous or 166 * page cache page while the page is migrated to device 167 * private memory. 168 * ZONE_DEVICE MEMORY_DEVICE_FS_DAX pages also 169 * use the mapping, index, and private fields when 170 * pmem backed DAX files are mapped. 171 */ 172 }; 173 174 /** @rcu_head: You can use this to free a page by RCU. */ 175 struct rcu_head rcu_head; 176 }; 177 178 union { /* This union is 4 bytes in size. */ 179 /* 180 * If the page can be mapped to userspace, encodes the number 181 * of times this page is referenced by a page table. 182 */ 183 atomic_t _mapcount; 184 185 /* 186 * If the page is neither PageSlab nor mappable to userspace, 187 * the value stored here may help determine what this page 188 * is used for. See page-flags.h for a list of page types 189 * which are currently stored here. 190 */ 191 unsigned int page_type; 192 }; 193 194 /* Usage count. *DO NOT USE DIRECTLY*. See page_ref.h */ 195 atomic_t _refcount; 196 197 #ifdef CONFIG_MEMCG 198 unsigned long memcg_data; 199 #endif 200 201 /* 202 * On machines where all RAM is mapped into kernel address space, 203 * we can simply calculate the virtual address. On machines with 204 * highmem some memory is mapped into kernel virtual memory 205 * dynamically, so we need a place to store that address. 206 * Note that this field could be 16 bits on x86 ... ;) 207 * 208 * Architectures with slow multiplication can define 209 * WANT_PAGE_VIRTUAL in asm/page.h 210 */ 211 #if defined(WANT_PAGE_VIRTUAL) 212 void *virtual; /* Kernel virtual address (NULL if 213 not kmapped, ie. highmem) */ 214 #endif /* WANT_PAGE_VIRTUAL */ 215 216 #ifdef CONFIG_KMSAN 217 /* 218 * KMSAN metadata for this page: 219 * - shadow page: every bit indicates whether the corresponding 220 * bit of the original page is initialized (0) or not (1); 221 * - origin page: every 4 bytes contain an id of the stack trace 222 * where the uninitialized value was created. 223 */ 224 struct page *kmsan_shadow; 225 struct page *kmsan_origin; 226 #endif 227 228 #ifdef LAST_CPUPID_NOT_IN_PAGE_FLAGS 229 int _last_cpupid; 230 #endif 231 } _struct_page_alignment; 232 233 /* 234 * struct encoded_page - a nonexistent type marking this pointer 235 * 236 * An 'encoded_page' pointer is a pointer to a regular 'struct page', but 237 * with the low bits of the pointer indicating extra context-dependent 238 * information. Not super-common, but happens in mmu_gather and mlock 239 * handling, and this acts as a type system check on that use. 240 * 241 * We only really have two guaranteed bits in general, although you could 242 * play with 'struct page' alignment (see CONFIG_HAVE_ALIGNED_STRUCT_PAGE) 243 * for more. 244 * 245 * Use the supplied helper functions to endcode/decode the pointer and bits. 246 */ 247 struct encoded_page; 248 #define ENCODE_PAGE_BITS 3ul 249 static __always_inline struct encoded_page *encode_page(struct page *page, unsigned long flags) 250 { 251 BUILD_BUG_ON(flags > ENCODE_PAGE_BITS); 252 return (struct encoded_page *)(flags | (unsigned long)page); 253 } 254 255 static inline unsigned long encoded_page_flags(struct encoded_page *page) 256 { 257 return ENCODE_PAGE_BITS & (unsigned long)page; 258 } 259 260 static inline struct page *encoded_page_ptr(struct encoded_page *page) 261 { 262 return (struct page *)(~ENCODE_PAGE_BITS & (unsigned long)page); 263 } 264 265 /** 266 * struct folio - Represents a contiguous set of bytes. 267 * @flags: Identical to the page flags. 268 * @lru: Least Recently Used list; tracks how recently this folio was used. 269 * @mlock_count: Number of times this folio has been pinned by mlock(). 270 * @mapping: The file this page belongs to, or refers to the anon_vma for 271 * anonymous memory. 272 * @index: Offset within the file, in units of pages. For anonymous memory, 273 * this is the index from the beginning of the mmap. 274 * @private: Filesystem per-folio data (see folio_attach_private()). 275 * Used for swp_entry_t if folio_test_swapcache(). 276 * @_mapcount: Do not access this member directly. Use folio_mapcount() to 277 * find out how many times this folio is mapped by userspace. 278 * @_refcount: Do not access this member directly. Use folio_ref_count() 279 * to find how many references there are to this folio. 280 * @memcg_data: Memory Control Group data. 281 * @_folio_dtor: Which destructor to use for this folio. 282 * @_folio_order: Do not use directly, call folio_order(). 283 * @_entire_mapcount: Do not use directly, call folio_entire_mapcount(). 284 * @_nr_pages_mapped: Do not use directly, call folio_mapcount(). 285 * @_pincount: Do not use directly, call folio_maybe_dma_pinned(). 286 * @_folio_nr_pages: Do not use directly, call folio_nr_pages(). 287 * @_hugetlb_subpool: Do not use directly, use accessor in hugetlb.h. 288 * @_hugetlb_cgroup: Do not use directly, use accessor in hugetlb_cgroup.h. 289 * @_hugetlb_cgroup_rsvd: Do not use directly, use accessor in hugetlb_cgroup.h. 290 * @_hugetlb_hwpoison: Do not use directly, call raw_hwp_list_head(). 291 * @_deferred_list: Folios to be split under memory pressure. 292 * 293 * A folio is a physically, virtually and logically contiguous set 294 * of bytes. It is a power-of-two in size, and it is aligned to that 295 * same power-of-two. It is at least as large as %PAGE_SIZE. If it is 296 * in the page cache, it is at a file offset which is a multiple of that 297 * power-of-two. It may be mapped into userspace at an address which is 298 * at an arbitrary page offset, but its kernel virtual address is aligned 299 * to its size. 300 */ 301 struct folio { 302 /* private: don't document the anon union */ 303 union { 304 struct { 305 /* public: */ 306 unsigned long flags; 307 union { 308 struct list_head lru; 309 /* private: avoid cluttering the output */ 310 struct { 311 void *__filler; 312 /* public: */ 313 unsigned int mlock_count; 314 /* private: */ 315 }; 316 /* public: */ 317 }; 318 struct address_space *mapping; 319 pgoff_t index; 320 void *private; 321 atomic_t _mapcount; 322 atomic_t _refcount; 323 #ifdef CONFIG_MEMCG 324 unsigned long memcg_data; 325 #endif 326 /* private: the union with struct page is transitional */ 327 }; 328 struct page page; 329 }; 330 union { 331 struct { 332 unsigned long _flags_1; 333 unsigned long _head_1; 334 /* public: */ 335 unsigned char _folio_dtor; 336 unsigned char _folio_order; 337 atomic_t _entire_mapcount; 338 atomic_t _nr_pages_mapped; 339 atomic_t _pincount; 340 #ifdef CONFIG_64BIT 341 unsigned int _folio_nr_pages; 342 #endif 343 /* private: the union with struct page is transitional */ 344 }; 345 struct page __page_1; 346 }; 347 union { 348 struct { 349 unsigned long _flags_2; 350 unsigned long _head_2; 351 /* public: */ 352 void *_hugetlb_subpool; 353 void *_hugetlb_cgroup; 354 void *_hugetlb_cgroup_rsvd; 355 void *_hugetlb_hwpoison; 356 /* private: the union with struct page is transitional */ 357 }; 358 struct { 359 unsigned long _flags_2a; 360 unsigned long _head_2a; 361 /* public: */ 362 struct list_head _deferred_list; 363 /* private: the union with struct page is transitional */ 364 }; 365 struct page __page_2; 366 }; 367 }; 368 369 #define FOLIO_MATCH(pg, fl) \ 370 static_assert(offsetof(struct page, pg) == offsetof(struct folio, fl)) 371 FOLIO_MATCH(flags, flags); 372 FOLIO_MATCH(lru, lru); 373 FOLIO_MATCH(mapping, mapping); 374 FOLIO_MATCH(compound_head, lru); 375 FOLIO_MATCH(index, index); 376 FOLIO_MATCH(private, private); 377 FOLIO_MATCH(_mapcount, _mapcount); 378 FOLIO_MATCH(_refcount, _refcount); 379 #ifdef CONFIG_MEMCG 380 FOLIO_MATCH(memcg_data, memcg_data); 381 #endif 382 #undef FOLIO_MATCH 383 #define FOLIO_MATCH(pg, fl) \ 384 static_assert(offsetof(struct folio, fl) == \ 385 offsetof(struct page, pg) + sizeof(struct page)) 386 FOLIO_MATCH(flags, _flags_1); 387 FOLIO_MATCH(compound_head, _head_1); 388 #undef FOLIO_MATCH 389 #define FOLIO_MATCH(pg, fl) \ 390 static_assert(offsetof(struct folio, fl) == \ 391 offsetof(struct page, pg) + 2 * sizeof(struct page)) 392 FOLIO_MATCH(flags, _flags_2); 393 FOLIO_MATCH(compound_head, _head_2); 394 #undef FOLIO_MATCH 395 396 /* 397 * Used for sizing the vmemmap region on some architectures 398 */ 399 #define STRUCT_PAGE_MAX_SHIFT (order_base_2(sizeof(struct page))) 400 401 #define PAGE_FRAG_CACHE_MAX_SIZE __ALIGN_MASK(32768, ~PAGE_MASK) 402 #define PAGE_FRAG_CACHE_MAX_ORDER get_order(PAGE_FRAG_CACHE_MAX_SIZE) 403 404 /* 405 * page_private can be used on tail pages. However, PagePrivate is only 406 * checked by the VM on the head page. So page_private on the tail pages 407 * should be used for data that's ancillary to the head page (eg attaching 408 * buffer heads to tail pages after attaching buffer heads to the head page) 409 */ 410 #define page_private(page) ((page)->private) 411 412 static inline void set_page_private(struct page *page, unsigned long private) 413 { 414 page->private = private; 415 } 416 417 static inline void *folio_get_private(struct folio *folio) 418 { 419 return folio->private; 420 } 421 422 struct page_frag_cache { 423 void * va; 424 #if (PAGE_SIZE < PAGE_FRAG_CACHE_MAX_SIZE) 425 __u16 offset; 426 __u16 size; 427 #else 428 __u32 offset; 429 #endif 430 /* we maintain a pagecount bias, so that we dont dirty cache line 431 * containing page->_refcount every time we allocate a fragment. 432 */ 433 unsigned int pagecnt_bias; 434 bool pfmemalloc; 435 }; 436 437 typedef unsigned long vm_flags_t; 438 439 /* 440 * A region containing a mapping of a non-memory backed file under NOMMU 441 * conditions. These are held in a global tree and are pinned by the VMAs that 442 * map parts of them. 443 */ 444 struct vm_region { 445 struct rb_node vm_rb; /* link in global region tree */ 446 vm_flags_t vm_flags; /* VMA vm_flags */ 447 unsigned long vm_start; /* start address of region */ 448 unsigned long vm_end; /* region initialised to here */ 449 unsigned long vm_top; /* region allocated to here */ 450 unsigned long vm_pgoff; /* the offset in vm_file corresponding to vm_start */ 451 struct file *vm_file; /* the backing file or NULL */ 452 453 int vm_usage; /* region usage count (access under nommu_region_sem) */ 454 bool vm_icache_flushed : 1; /* true if the icache has been flushed for 455 * this region */ 456 }; 457 458 #ifdef CONFIG_USERFAULTFD 459 #define NULL_VM_UFFD_CTX ((struct vm_userfaultfd_ctx) { NULL, }) 460 struct vm_userfaultfd_ctx { 461 struct userfaultfd_ctx *ctx; 462 }; 463 #else /* CONFIG_USERFAULTFD */ 464 #define NULL_VM_UFFD_CTX ((struct vm_userfaultfd_ctx) {}) 465 struct vm_userfaultfd_ctx {}; 466 #endif /* CONFIG_USERFAULTFD */ 467 468 struct anon_vma_name { 469 struct kref kref; 470 /* The name needs to be at the end because it is dynamically sized. */ 471 char name[]; 472 }; 473 474 struct vma_lock { 475 struct rw_semaphore lock; 476 }; 477 478 struct vma_numab_state { 479 unsigned long next_scan; 480 unsigned long next_pid_reset; 481 unsigned long access_pids[2]; 482 }; 483 484 /* 485 * This struct describes a virtual memory area. There is one of these 486 * per VM-area/task. A VM area is any part of the process virtual memory 487 * space that has a special rule for the page-fault handlers (ie a shared 488 * library, the executable area etc). 489 */ 490 struct vm_area_struct { 491 /* The first cache line has the info for VMA tree walking. */ 492 493 union { 494 struct { 495 /* VMA covers [vm_start; vm_end) addresses within mm */ 496 unsigned long vm_start; 497 unsigned long vm_end; 498 }; 499 #ifdef CONFIG_PER_VMA_LOCK 500 struct rcu_head vm_rcu; /* Used for deferred freeing. */ 501 #endif 502 }; 503 504 struct mm_struct *vm_mm; /* The address space we belong to. */ 505 pgprot_t vm_page_prot; /* Access permissions of this VMA. */ 506 507 /* 508 * Flags, see mm.h. 509 * To modify use vm_flags_{init|reset|set|clear|mod} functions. 510 */ 511 union { 512 const vm_flags_t vm_flags; 513 vm_flags_t __private __vm_flags; 514 }; 515 516 #ifdef CONFIG_PER_VMA_LOCK 517 int vm_lock_seq; 518 struct vma_lock *vm_lock; 519 520 /* Flag to indicate areas detached from the mm->mm_mt tree */ 521 bool detached; 522 #endif 523 524 /* 525 * For areas with an address space and backing store, 526 * linkage into the address_space->i_mmap interval tree. 527 * 528 */ 529 struct { 530 struct rb_node rb; 531 unsigned long rb_subtree_last; 532 } shared; 533 534 /* 535 * A file's MAP_PRIVATE vma can be in both i_mmap tree and anon_vma 536 * list, after a COW of one of the file pages. A MAP_SHARED vma 537 * can only be in the i_mmap tree. An anonymous MAP_PRIVATE, stack 538 * or brk vma (with NULL file) can only be in an anon_vma list. 539 */ 540 struct list_head anon_vma_chain; /* Serialized by mmap_lock & 541 * page_table_lock */ 542 struct anon_vma *anon_vma; /* Serialized by page_table_lock */ 543 544 /* Function pointers to deal with this struct. */ 545 const struct vm_operations_struct *vm_ops; 546 547 /* Information about our backing store: */ 548 unsigned long vm_pgoff; /* Offset (within vm_file) in PAGE_SIZE 549 units */ 550 struct file * vm_file; /* File we map to (can be NULL). */ 551 void * vm_private_data; /* was vm_pte (shared mem) */ 552 553 #ifdef CONFIG_ANON_VMA_NAME 554 /* 555 * For private and shared anonymous mappings, a pointer to a null 556 * terminated string containing the name given to the vma, or NULL if 557 * unnamed. Serialized by mmap_lock. Use anon_vma_name to access. 558 */ 559 struct anon_vma_name *anon_name; 560 #endif 561 #ifdef CONFIG_SWAP 562 atomic_long_t swap_readahead_info; 563 #endif 564 #ifndef CONFIG_MMU 565 struct vm_region *vm_region; /* NOMMU mapping region */ 566 #endif 567 #ifdef CONFIG_NUMA 568 struct mempolicy *vm_policy; /* NUMA policy for the VMA */ 569 #endif 570 #ifdef CONFIG_NUMA_BALANCING 571 struct vma_numab_state *numab_state; /* NUMA Balancing state */ 572 #endif 573 struct vm_userfaultfd_ctx vm_userfaultfd_ctx; 574 } __randomize_layout; 575 576 #ifdef CONFIG_SCHED_MM_CID 577 struct mm_cid { 578 u64 time; 579 int cid; 580 }; 581 #endif 582 583 struct kioctx_table; 584 struct mm_struct { 585 struct { 586 struct maple_tree mm_mt; 587 #ifdef CONFIG_MMU 588 unsigned long (*get_unmapped_area) (struct file *filp, 589 unsigned long addr, unsigned long len, 590 unsigned long pgoff, unsigned long flags); 591 #endif 592 unsigned long mmap_base; /* base of mmap area */ 593 unsigned long mmap_legacy_base; /* base of mmap area in bottom-up allocations */ 594 #ifdef CONFIG_HAVE_ARCH_COMPAT_MMAP_BASES 595 /* Base addresses for compatible mmap() */ 596 unsigned long mmap_compat_base; 597 unsigned long mmap_compat_legacy_base; 598 #endif 599 unsigned long task_size; /* size of task vm space */ 600 pgd_t * pgd; 601 602 #ifdef CONFIG_MEMBARRIER 603 /** 604 * @membarrier_state: Flags controlling membarrier behavior. 605 * 606 * This field is close to @pgd to hopefully fit in the same 607 * cache-line, which needs to be touched by switch_mm(). 608 */ 609 atomic_t membarrier_state; 610 #endif 611 612 /** 613 * @mm_users: The number of users including userspace. 614 * 615 * Use mmget()/mmget_not_zero()/mmput() to modify. When this 616 * drops to 0 (i.e. when the task exits and there are no other 617 * temporary reference holders), we also release a reference on 618 * @mm_count (which may then free the &struct mm_struct if 619 * @mm_count also drops to 0). 620 */ 621 atomic_t mm_users; 622 623 /** 624 * @mm_count: The number of references to &struct mm_struct 625 * (@mm_users count as 1). 626 * 627 * Use mmgrab()/mmdrop() to modify. When this drops to 0, the 628 * &struct mm_struct is freed. 629 */ 630 atomic_t mm_count; 631 #ifdef CONFIG_SCHED_MM_CID 632 /** 633 * @pcpu_cid: Per-cpu current cid. 634 * 635 * Keep track of the currently allocated mm_cid for each cpu. 636 * The per-cpu mm_cid values are serialized by their respective 637 * runqueue locks. 638 */ 639 struct mm_cid __percpu *pcpu_cid; 640 /* 641 * @mm_cid_next_scan: Next mm_cid scan (in jiffies). 642 * 643 * When the next mm_cid scan is due (in jiffies). 644 */ 645 unsigned long mm_cid_next_scan; 646 #endif 647 #ifdef CONFIG_MMU 648 atomic_long_t pgtables_bytes; /* size of all page tables */ 649 #endif 650 int map_count; /* number of VMAs */ 651 652 spinlock_t page_table_lock; /* Protects page tables and some 653 * counters 654 */ 655 /* 656 * With some kernel config, the current mmap_lock's offset 657 * inside 'mm_struct' is at 0x120, which is very optimal, as 658 * its two hot fields 'count' and 'owner' sit in 2 different 659 * cachelines, and when mmap_lock is highly contended, both 660 * of the 2 fields will be accessed frequently, current layout 661 * will help to reduce cache bouncing. 662 * 663 * So please be careful with adding new fields before 664 * mmap_lock, which can easily push the 2 fields into one 665 * cacheline. 666 */ 667 struct rw_semaphore mmap_lock; 668 669 struct list_head mmlist; /* List of maybe swapped mm's. These 670 * are globally strung together off 671 * init_mm.mmlist, and are protected 672 * by mmlist_lock 673 */ 674 #ifdef CONFIG_PER_VMA_LOCK 675 int mm_lock_seq; 676 #endif 677 678 679 unsigned long hiwater_rss; /* High-watermark of RSS usage */ 680 unsigned long hiwater_vm; /* High-water virtual memory usage */ 681 682 unsigned long total_vm; /* Total pages mapped */ 683 unsigned long locked_vm; /* Pages that have PG_mlocked set */ 684 atomic64_t pinned_vm; /* Refcount permanently increased */ 685 unsigned long data_vm; /* VM_WRITE & ~VM_SHARED & ~VM_STACK */ 686 unsigned long exec_vm; /* VM_EXEC & ~VM_WRITE & ~VM_STACK */ 687 unsigned long stack_vm; /* VM_STACK */ 688 unsigned long def_flags; 689 690 /** 691 * @write_protect_seq: Locked when any thread is write 692 * protecting pages mapped by this mm to enforce a later COW, 693 * for instance during page table copying for fork(). 694 */ 695 seqcount_t write_protect_seq; 696 697 spinlock_t arg_lock; /* protect the below fields */ 698 699 unsigned long start_code, end_code, start_data, end_data; 700 unsigned long start_brk, brk, start_stack; 701 unsigned long arg_start, arg_end, env_start, env_end; 702 703 unsigned long saved_auxv[AT_VECTOR_SIZE]; /* for /proc/PID/auxv */ 704 705 struct percpu_counter rss_stat[NR_MM_COUNTERS]; 706 707 struct linux_binfmt *binfmt; 708 709 /* Architecture-specific MM context */ 710 mm_context_t context; 711 712 unsigned long flags; /* Must use atomic bitops to access */ 713 714 #ifdef CONFIG_AIO 715 spinlock_t ioctx_lock; 716 struct kioctx_table __rcu *ioctx_table; 717 #endif 718 #ifdef CONFIG_MEMCG 719 /* 720 * "owner" points to a task that is regarded as the canonical 721 * user/owner of this mm. All of the following must be true in 722 * order for it to be changed: 723 * 724 * current == mm->owner 725 * current->mm != mm 726 * new_owner->mm == mm 727 * new_owner->alloc_lock is held 728 */ 729 struct task_struct __rcu *owner; 730 #endif 731 struct user_namespace *user_ns; 732 733 /* store ref to file /proc/<pid>/exe symlink points to */ 734 struct file __rcu *exe_file; 735 #ifdef CONFIG_MMU_NOTIFIER 736 struct mmu_notifier_subscriptions *notifier_subscriptions; 737 #endif 738 #if defined(CONFIG_TRANSPARENT_HUGEPAGE) && !USE_SPLIT_PMD_PTLOCKS 739 pgtable_t pmd_huge_pte; /* protected by page_table_lock */ 740 #endif 741 #ifdef CONFIG_NUMA_BALANCING 742 /* 743 * numa_next_scan is the next time that PTEs will be remapped 744 * PROT_NONE to trigger NUMA hinting faults; such faults gather 745 * statistics and migrate pages to new nodes if necessary. 746 */ 747 unsigned long numa_next_scan; 748 749 /* Restart point for scanning and remapping PTEs. */ 750 unsigned long numa_scan_offset; 751 752 /* numa_scan_seq prevents two threads remapping PTEs. */ 753 int numa_scan_seq; 754 #endif 755 /* 756 * An operation with batched TLB flushing is going on. Anything 757 * that can move process memory needs to flush the TLB when 758 * moving a PROT_NONE mapped page. 759 */ 760 atomic_t tlb_flush_pending; 761 #ifdef CONFIG_ARCH_WANT_BATCHED_UNMAP_TLB_FLUSH 762 /* See flush_tlb_batched_pending() */ 763 atomic_t tlb_flush_batched; 764 #endif 765 struct uprobes_state uprobes_state; 766 #ifdef CONFIG_PREEMPT_RT 767 struct rcu_head delayed_drop; 768 #endif 769 #ifdef CONFIG_HUGETLB_PAGE 770 atomic_long_t hugetlb_usage; 771 #endif 772 struct work_struct async_put_work; 773 774 #ifdef CONFIG_IOMMU_SVA 775 u32 pasid; 776 #endif 777 #ifdef CONFIG_KSM 778 /* 779 * Represent how many pages of this process are involved in KSM 780 * merging. 781 */ 782 unsigned long ksm_merging_pages; 783 /* 784 * Represent how many pages are checked for ksm merging 785 * including merged and not merged. 786 */ 787 unsigned long ksm_rmap_items; 788 #endif 789 #ifdef CONFIG_LRU_GEN 790 struct { 791 /* this mm_struct is on lru_gen_mm_list */ 792 struct list_head list; 793 /* 794 * Set when switching to this mm_struct, as a hint of 795 * whether it has been used since the last time per-node 796 * page table walkers cleared the corresponding bits. 797 */ 798 unsigned long bitmap; 799 #ifdef CONFIG_MEMCG 800 /* points to the memcg of "owner" above */ 801 struct mem_cgroup *memcg; 802 #endif 803 } lru_gen; 804 #endif /* CONFIG_LRU_GEN */ 805 } __randomize_layout; 806 807 /* 808 * The mm_cpumask needs to be at the end of mm_struct, because it 809 * is dynamically sized based on nr_cpu_ids. 810 */ 811 unsigned long cpu_bitmap[]; 812 }; 813 814 #define MM_MT_FLAGS (MT_FLAGS_ALLOC_RANGE | MT_FLAGS_LOCK_EXTERN | \ 815 MT_FLAGS_USE_RCU) 816 extern struct mm_struct init_mm; 817 818 /* Pointer magic because the dynamic array size confuses some compilers. */ 819 static inline void mm_init_cpumask(struct mm_struct *mm) 820 { 821 unsigned long cpu_bitmap = (unsigned long)mm; 822 823 cpu_bitmap += offsetof(struct mm_struct, cpu_bitmap); 824 cpumask_clear((struct cpumask *)cpu_bitmap); 825 } 826 827 /* Future-safe accessor for struct mm_struct's cpu_vm_mask. */ 828 static inline cpumask_t *mm_cpumask(struct mm_struct *mm) 829 { 830 return (struct cpumask *)&mm->cpu_bitmap; 831 } 832 833 #ifdef CONFIG_LRU_GEN 834 835 struct lru_gen_mm_list { 836 /* mm_struct list for page table walkers */ 837 struct list_head fifo; 838 /* protects the list above */ 839 spinlock_t lock; 840 }; 841 842 void lru_gen_add_mm(struct mm_struct *mm); 843 void lru_gen_del_mm(struct mm_struct *mm); 844 #ifdef CONFIG_MEMCG 845 void lru_gen_migrate_mm(struct mm_struct *mm); 846 #endif 847 848 static inline void lru_gen_init_mm(struct mm_struct *mm) 849 { 850 INIT_LIST_HEAD(&mm->lru_gen.list); 851 mm->lru_gen.bitmap = 0; 852 #ifdef CONFIG_MEMCG 853 mm->lru_gen.memcg = NULL; 854 #endif 855 } 856 857 static inline void lru_gen_use_mm(struct mm_struct *mm) 858 { 859 /* 860 * When the bitmap is set, page reclaim knows this mm_struct has been 861 * used since the last time it cleared the bitmap. So it might be worth 862 * walking the page tables of this mm_struct to clear the accessed bit. 863 */ 864 WRITE_ONCE(mm->lru_gen.bitmap, -1); 865 } 866 867 #else /* !CONFIG_LRU_GEN */ 868 869 static inline void lru_gen_add_mm(struct mm_struct *mm) 870 { 871 } 872 873 static inline void lru_gen_del_mm(struct mm_struct *mm) 874 { 875 } 876 877 #ifdef CONFIG_MEMCG 878 static inline void lru_gen_migrate_mm(struct mm_struct *mm) 879 { 880 } 881 #endif 882 883 static inline void lru_gen_init_mm(struct mm_struct *mm) 884 { 885 } 886 887 static inline void lru_gen_use_mm(struct mm_struct *mm) 888 { 889 } 890 891 #endif /* CONFIG_LRU_GEN */ 892 893 struct vma_iterator { 894 struct ma_state mas; 895 }; 896 897 #define VMA_ITERATOR(name, __mm, __addr) \ 898 struct vma_iterator name = { \ 899 .mas = { \ 900 .tree = &(__mm)->mm_mt, \ 901 .index = __addr, \ 902 .node = MAS_START, \ 903 }, \ 904 } 905 906 static inline void vma_iter_init(struct vma_iterator *vmi, 907 struct mm_struct *mm, unsigned long addr) 908 { 909 mas_init(&vmi->mas, &mm->mm_mt, addr); 910 } 911 912 #ifdef CONFIG_SCHED_MM_CID 913 914 enum mm_cid_state { 915 MM_CID_UNSET = -1U, /* Unset state has lazy_put flag set. */ 916 MM_CID_LAZY_PUT = (1U << 31), 917 }; 918 919 static inline bool mm_cid_is_unset(int cid) 920 { 921 return cid == MM_CID_UNSET; 922 } 923 924 static inline bool mm_cid_is_lazy_put(int cid) 925 { 926 return !mm_cid_is_unset(cid) && (cid & MM_CID_LAZY_PUT); 927 } 928 929 static inline bool mm_cid_is_valid(int cid) 930 { 931 return !(cid & MM_CID_LAZY_PUT); 932 } 933 934 static inline int mm_cid_set_lazy_put(int cid) 935 { 936 return cid | MM_CID_LAZY_PUT; 937 } 938 939 static inline int mm_cid_clear_lazy_put(int cid) 940 { 941 return cid & ~MM_CID_LAZY_PUT; 942 } 943 944 /* Accessor for struct mm_struct's cidmask. */ 945 static inline cpumask_t *mm_cidmask(struct mm_struct *mm) 946 { 947 unsigned long cid_bitmap = (unsigned long)mm; 948 949 cid_bitmap += offsetof(struct mm_struct, cpu_bitmap); 950 /* Skip cpu_bitmap */ 951 cid_bitmap += cpumask_size(); 952 return (struct cpumask *)cid_bitmap; 953 } 954 955 static inline void mm_init_cid(struct mm_struct *mm) 956 { 957 int i; 958 959 for_each_possible_cpu(i) { 960 struct mm_cid *pcpu_cid = per_cpu_ptr(mm->pcpu_cid, i); 961 962 pcpu_cid->cid = MM_CID_UNSET; 963 pcpu_cid->time = 0; 964 } 965 cpumask_clear(mm_cidmask(mm)); 966 } 967 968 static inline int mm_alloc_cid(struct mm_struct *mm) 969 { 970 mm->pcpu_cid = alloc_percpu(struct mm_cid); 971 if (!mm->pcpu_cid) 972 return -ENOMEM; 973 mm_init_cid(mm); 974 return 0; 975 } 976 977 static inline void mm_destroy_cid(struct mm_struct *mm) 978 { 979 free_percpu(mm->pcpu_cid); 980 mm->pcpu_cid = NULL; 981 } 982 983 static inline unsigned int mm_cid_size(void) 984 { 985 return cpumask_size(); 986 } 987 #else /* CONFIG_SCHED_MM_CID */ 988 static inline void mm_init_cid(struct mm_struct *mm) { } 989 static inline int mm_alloc_cid(struct mm_struct *mm) { return 0; } 990 static inline void mm_destroy_cid(struct mm_struct *mm) { } 991 static inline unsigned int mm_cid_size(void) 992 { 993 return 0; 994 } 995 #endif /* CONFIG_SCHED_MM_CID */ 996 997 struct mmu_gather; 998 extern void tlb_gather_mmu(struct mmu_gather *tlb, struct mm_struct *mm); 999 extern void tlb_gather_mmu_fullmm(struct mmu_gather *tlb, struct mm_struct *mm); 1000 extern void tlb_finish_mmu(struct mmu_gather *tlb); 1001 1002 struct vm_fault; 1003 1004 /** 1005 * typedef vm_fault_t - Return type for page fault handlers. 1006 * 1007 * Page fault handlers return a bitmask of %VM_FAULT values. 1008 */ 1009 typedef __bitwise unsigned int vm_fault_t; 1010 1011 /** 1012 * enum vm_fault_reason - Page fault handlers return a bitmask of 1013 * these values to tell the core VM what happened when handling the 1014 * fault. Used to decide whether a process gets delivered SIGBUS or 1015 * just gets major/minor fault counters bumped up. 1016 * 1017 * @VM_FAULT_OOM: Out Of Memory 1018 * @VM_FAULT_SIGBUS: Bad access 1019 * @VM_FAULT_MAJOR: Page read from storage 1020 * @VM_FAULT_HWPOISON: Hit poisoned small page 1021 * @VM_FAULT_HWPOISON_LARGE: Hit poisoned large page. Index encoded 1022 * in upper bits 1023 * @VM_FAULT_SIGSEGV: segmentation fault 1024 * @VM_FAULT_NOPAGE: ->fault installed the pte, not return page 1025 * @VM_FAULT_LOCKED: ->fault locked the returned page 1026 * @VM_FAULT_RETRY: ->fault blocked, must retry 1027 * @VM_FAULT_FALLBACK: huge page fault failed, fall back to small 1028 * @VM_FAULT_DONE_COW: ->fault has fully handled COW 1029 * @VM_FAULT_NEEDDSYNC: ->fault did not modify page tables and needs 1030 * fsync() to complete (for synchronous page faults 1031 * in DAX) 1032 * @VM_FAULT_COMPLETED: ->fault completed, meanwhile mmap lock released 1033 * @VM_FAULT_HINDEX_MASK: mask HINDEX value 1034 * 1035 */ 1036 enum vm_fault_reason { 1037 VM_FAULT_OOM = (__force vm_fault_t)0x000001, 1038 VM_FAULT_SIGBUS = (__force vm_fault_t)0x000002, 1039 VM_FAULT_MAJOR = (__force vm_fault_t)0x000004, 1040 VM_FAULT_HWPOISON = (__force vm_fault_t)0x000010, 1041 VM_FAULT_HWPOISON_LARGE = (__force vm_fault_t)0x000020, 1042 VM_FAULT_SIGSEGV = (__force vm_fault_t)0x000040, 1043 VM_FAULT_NOPAGE = (__force vm_fault_t)0x000100, 1044 VM_FAULT_LOCKED = (__force vm_fault_t)0x000200, 1045 VM_FAULT_RETRY = (__force vm_fault_t)0x000400, 1046 VM_FAULT_FALLBACK = (__force vm_fault_t)0x000800, 1047 VM_FAULT_DONE_COW = (__force vm_fault_t)0x001000, 1048 VM_FAULT_NEEDDSYNC = (__force vm_fault_t)0x002000, 1049 VM_FAULT_COMPLETED = (__force vm_fault_t)0x004000, 1050 VM_FAULT_HINDEX_MASK = (__force vm_fault_t)0x0f0000, 1051 }; 1052 1053 /* Encode hstate index for a hwpoisoned large page */ 1054 #define VM_FAULT_SET_HINDEX(x) ((__force vm_fault_t)((x) << 16)) 1055 #define VM_FAULT_GET_HINDEX(x) (((__force unsigned int)(x) >> 16) & 0xf) 1056 1057 #define VM_FAULT_ERROR (VM_FAULT_OOM | VM_FAULT_SIGBUS | \ 1058 VM_FAULT_SIGSEGV | VM_FAULT_HWPOISON | \ 1059 VM_FAULT_HWPOISON_LARGE | VM_FAULT_FALLBACK) 1060 1061 #define VM_FAULT_RESULT_TRACE \ 1062 { VM_FAULT_OOM, "OOM" }, \ 1063 { VM_FAULT_SIGBUS, "SIGBUS" }, \ 1064 { VM_FAULT_MAJOR, "MAJOR" }, \ 1065 { VM_FAULT_HWPOISON, "HWPOISON" }, \ 1066 { VM_FAULT_HWPOISON_LARGE, "HWPOISON_LARGE" }, \ 1067 { VM_FAULT_SIGSEGV, "SIGSEGV" }, \ 1068 { VM_FAULT_NOPAGE, "NOPAGE" }, \ 1069 { VM_FAULT_LOCKED, "LOCKED" }, \ 1070 { VM_FAULT_RETRY, "RETRY" }, \ 1071 { VM_FAULT_FALLBACK, "FALLBACK" }, \ 1072 { VM_FAULT_DONE_COW, "DONE_COW" }, \ 1073 { VM_FAULT_NEEDDSYNC, "NEEDDSYNC" } 1074 1075 struct vm_special_mapping { 1076 const char *name; /* The name, e.g. "[vdso]". */ 1077 1078 /* 1079 * If .fault is not provided, this points to a 1080 * NULL-terminated array of pages that back the special mapping. 1081 * 1082 * This must not be NULL unless .fault is provided. 1083 */ 1084 struct page **pages; 1085 1086 /* 1087 * If non-NULL, then this is called to resolve page faults 1088 * on the special mapping. If used, .pages is not checked. 1089 */ 1090 vm_fault_t (*fault)(const struct vm_special_mapping *sm, 1091 struct vm_area_struct *vma, 1092 struct vm_fault *vmf); 1093 1094 int (*mremap)(const struct vm_special_mapping *sm, 1095 struct vm_area_struct *new_vma); 1096 }; 1097 1098 enum tlb_flush_reason { 1099 TLB_FLUSH_ON_TASK_SWITCH, 1100 TLB_REMOTE_SHOOTDOWN, 1101 TLB_LOCAL_SHOOTDOWN, 1102 TLB_LOCAL_MM_SHOOTDOWN, 1103 TLB_REMOTE_SEND_IPI, 1104 NR_TLB_FLUSH_REASONS, 1105 }; 1106 1107 /* 1108 * A swap entry has to fit into a "unsigned long", as the entry is hidden 1109 * in the "index" field of the swapper address space. 1110 */ 1111 typedef struct { 1112 unsigned long val; 1113 } swp_entry_t; 1114 1115 /** 1116 * enum fault_flag - Fault flag definitions. 1117 * @FAULT_FLAG_WRITE: Fault was a write fault. 1118 * @FAULT_FLAG_MKWRITE: Fault was mkwrite of existing PTE. 1119 * @FAULT_FLAG_ALLOW_RETRY: Allow to retry the fault if blocked. 1120 * @FAULT_FLAG_RETRY_NOWAIT: Don't drop mmap_lock and wait when retrying. 1121 * @FAULT_FLAG_KILLABLE: The fault task is in SIGKILL killable region. 1122 * @FAULT_FLAG_TRIED: The fault has been tried once. 1123 * @FAULT_FLAG_USER: The fault originated in userspace. 1124 * @FAULT_FLAG_REMOTE: The fault is not for current task/mm. 1125 * @FAULT_FLAG_INSTRUCTION: The fault was during an instruction fetch. 1126 * @FAULT_FLAG_INTERRUPTIBLE: The fault can be interrupted by non-fatal signals. 1127 * @FAULT_FLAG_UNSHARE: The fault is an unsharing request to break COW in a 1128 * COW mapping, making sure that an exclusive anon page is 1129 * mapped after the fault. 1130 * @FAULT_FLAG_ORIG_PTE_VALID: whether the fault has vmf->orig_pte cached. 1131 * We should only access orig_pte if this flag set. 1132 * @FAULT_FLAG_VMA_LOCK: The fault is handled under VMA lock. 1133 * 1134 * About @FAULT_FLAG_ALLOW_RETRY and @FAULT_FLAG_TRIED: we can specify 1135 * whether we would allow page faults to retry by specifying these two 1136 * fault flags correctly. Currently there can be three legal combinations: 1137 * 1138 * (a) ALLOW_RETRY and !TRIED: this means the page fault allows retry, and 1139 * this is the first try 1140 * 1141 * (b) ALLOW_RETRY and TRIED: this means the page fault allows retry, and 1142 * we've already tried at least once 1143 * 1144 * (c) !ALLOW_RETRY and !TRIED: this means the page fault does not allow retry 1145 * 1146 * The unlisted combination (!ALLOW_RETRY && TRIED) is illegal and should never 1147 * be used. Note that page faults can be allowed to retry for multiple times, 1148 * in which case we'll have an initial fault with flags (a) then later on 1149 * continuous faults with flags (b). We should always try to detect pending 1150 * signals before a retry to make sure the continuous page faults can still be 1151 * interrupted if necessary. 1152 * 1153 * The combination FAULT_FLAG_WRITE|FAULT_FLAG_UNSHARE is illegal. 1154 * FAULT_FLAG_UNSHARE is ignored and treated like an ordinary read fault when 1155 * applied to mappings that are not COW mappings. 1156 */ 1157 enum fault_flag { 1158 FAULT_FLAG_WRITE = 1 << 0, 1159 FAULT_FLAG_MKWRITE = 1 << 1, 1160 FAULT_FLAG_ALLOW_RETRY = 1 << 2, 1161 FAULT_FLAG_RETRY_NOWAIT = 1 << 3, 1162 FAULT_FLAG_KILLABLE = 1 << 4, 1163 FAULT_FLAG_TRIED = 1 << 5, 1164 FAULT_FLAG_USER = 1 << 6, 1165 FAULT_FLAG_REMOTE = 1 << 7, 1166 FAULT_FLAG_INSTRUCTION = 1 << 8, 1167 FAULT_FLAG_INTERRUPTIBLE = 1 << 9, 1168 FAULT_FLAG_UNSHARE = 1 << 10, 1169 FAULT_FLAG_ORIG_PTE_VALID = 1 << 11, 1170 FAULT_FLAG_VMA_LOCK = 1 << 12, 1171 }; 1172 1173 typedef unsigned int __bitwise zap_flags_t; 1174 1175 /* 1176 * FOLL_PIN and FOLL_LONGTERM may be used in various combinations with each 1177 * other. Here is what they mean, and how to use them: 1178 * 1179 * 1180 * FIXME: For pages which are part of a filesystem, mappings are subject to the 1181 * lifetime enforced by the filesystem and we need guarantees that longterm 1182 * users like RDMA and V4L2 only establish mappings which coordinate usage with 1183 * the filesystem. Ideas for this coordination include revoking the longterm 1184 * pin, delaying writeback, bounce buffer page writeback, etc. As FS DAX was 1185 * added after the problem with filesystems was found FS DAX VMAs are 1186 * specifically failed. Filesystem pages are still subject to bugs and use of 1187 * FOLL_LONGTERM should be avoided on those pages. 1188 * 1189 * In the CMA case: long term pins in a CMA region would unnecessarily fragment 1190 * that region. And so, CMA attempts to migrate the page before pinning, when 1191 * FOLL_LONGTERM is specified. 1192 * 1193 * FOLL_PIN indicates that a special kind of tracking (not just page->_refcount, 1194 * but an additional pin counting system) will be invoked. This is intended for 1195 * anything that gets a page reference and then touches page data (for example, 1196 * Direct IO). This lets the filesystem know that some non-file-system entity is 1197 * potentially changing the pages' data. In contrast to FOLL_GET (whose pages 1198 * are released via put_page()), FOLL_PIN pages must be released, ultimately, by 1199 * a call to unpin_user_page(). 1200 * 1201 * FOLL_PIN is similar to FOLL_GET: both of these pin pages. They use different 1202 * and separate refcounting mechanisms, however, and that means that each has 1203 * its own acquire and release mechanisms: 1204 * 1205 * FOLL_GET: get_user_pages*() to acquire, and put_page() to release. 1206 * 1207 * FOLL_PIN: pin_user_pages*() to acquire, and unpin_user_pages to release. 1208 * 1209 * FOLL_PIN and FOLL_GET are mutually exclusive for a given function call. 1210 * (The underlying pages may experience both FOLL_GET-based and FOLL_PIN-based 1211 * calls applied to them, and that's perfectly OK. This is a constraint on the 1212 * callers, not on the pages.) 1213 * 1214 * FOLL_PIN should be set internally by the pin_user_pages*() APIs, never 1215 * directly by the caller. That's in order to help avoid mismatches when 1216 * releasing pages: get_user_pages*() pages must be released via put_page(), 1217 * while pin_user_pages*() pages must be released via unpin_user_page(). 1218 * 1219 * Please see Documentation/core-api/pin_user_pages.rst for more information. 1220 */ 1221 1222 enum { 1223 /* check pte is writable */ 1224 FOLL_WRITE = 1 << 0, 1225 /* do get_page on page */ 1226 FOLL_GET = 1 << 1, 1227 /* give error on hole if it would be zero */ 1228 FOLL_DUMP = 1 << 2, 1229 /* get_user_pages read/write w/o permission */ 1230 FOLL_FORCE = 1 << 3, 1231 /* 1232 * if a disk transfer is needed, start the IO and return without waiting 1233 * upon it 1234 */ 1235 FOLL_NOWAIT = 1 << 4, 1236 /* do not fault in pages */ 1237 FOLL_NOFAULT = 1 << 5, 1238 /* check page is hwpoisoned */ 1239 FOLL_HWPOISON = 1 << 6, 1240 /* don't do file mappings */ 1241 FOLL_ANON = 1 << 7, 1242 /* 1243 * FOLL_LONGTERM indicates that the page will be held for an indefinite 1244 * time period _often_ under userspace control. This is in contrast to 1245 * iov_iter_get_pages(), whose usages are transient. 1246 */ 1247 FOLL_LONGTERM = 1 << 8, 1248 /* split huge pmd before returning */ 1249 FOLL_SPLIT_PMD = 1 << 9, 1250 /* allow returning PCI P2PDMA pages */ 1251 FOLL_PCI_P2PDMA = 1 << 10, 1252 /* allow interrupts from generic signals */ 1253 FOLL_INTERRUPTIBLE = 1 << 11, 1254 1255 /* See also internal only FOLL flags in mm/internal.h */ 1256 }; 1257 1258 #endif /* _LINUX_MM_TYPES_H */ 1259