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      1 #ifndef _LINUX_MM_H
      2 #define _LINUX_MM_H
      3 
      4 #include <linux/sched.h>
      5 #include <linux/errno.h>
      6 #include <linux/capability.h>
      7 
      8 #ifdef __KERNEL__
      9 
     10 #include <linux/gfp.h>
     11 #include <linux/list.h>
     12 #include <linux/mmzone.h>
     13 #include <linux/rbtree.h>
     14 #include <linux/prio_tree.h>
     15 #include <linux/fs.h>
     16 #include <linux/mutex.h>
     17 #include <linux/debug_locks.h>
     18 
     19 struct mempolicy;
     20 struct anon_vma;
     21 
     22 #ifndef CONFIG_DISCONTIGMEM          /* Don't use mapnrs, do it properly */
     23 extern unsigned long max_mapnr;
     24 #endif
     25 
     26 extern unsigned long num_physpages;
     27 extern void * high_memory;
     28 extern unsigned long vmalloc_earlyreserve;
     29 extern int page_cluster;
     30 
     31 #ifdef CONFIG_SYSCTL
     32 extern int sysctl_legacy_va_layout;
     33 #else
     34 #define sysctl_legacy_va_layout 0
     35 #endif
     36 
     37 #include <asm/page.h>
     38 #include <asm/pgtable.h>
     39 #include <asm/processor.h>
     40 
     41 #define nth_page(page,n) pfn_to_page(page_to_pfn((page)) + (n))
     42 
     43 /*
     44  * Linux kernel virtual memory manager primitives.
     45  * The idea being to have a "virtual" mm in the same way
     46  * we have a virtual fs - giving a cleaner interface to the
     47  * mm details, and allowing different kinds of memory mappings
     48  * (from shared memory to executable loading to arbitrary
     49  * mmap() functions).
     50  */
     51 
     52 /*
     53  * This struct defines a memory VMM memory area. There is one of these
     54  * per VM-area/task.  A VM area is any part of the process virtual memory
     55  * space that has a special rule for the page-fault handlers (ie a shared
     56  * library, the executable area etc).
     57  */
     58 struct vm_area_struct {
     59 	struct mm_struct * vm_mm;	/* The address space we belong to. */
     60 	unsigned long vm_start;		/* Our start address within vm_mm. */
     61 	unsigned long vm_end;		/* The first byte after our end address
     62 					   within vm_mm. */
     63 
     64 	/* linked list of VM areas per task, sorted by address */
     65 	struct vm_area_struct *vm_next;
     66 
     67 	pgprot_t vm_page_prot;		/* Access permissions of this VMA. */
     68 	unsigned long vm_flags;		/* Flags, listed below. */
     69 
     70 	struct rb_node vm_rb;
     71 
     72 	/*
     73 	 * For areas with an address space and backing store,
     74 	 * linkage into the address_space->i_mmap prio tree, or
     75 	 * linkage to the list of like vmas hanging off its node, or
     76 	 * linkage of vma in the address_space->i_mmap_nonlinear list.
     77 	 */
     78 	union {
     79 		struct {
     80 			struct list_head list;
     81 			void *parent;	/* aligns with prio_tree_node parent */
     82 			struct vm_area_struct *head;
     83 		} vm_set;
     84 
     85 		struct raw_prio_tree_node prio_tree_node;
     86 	} shared;
     87 
     88 	/*
     89 	 * A file's MAP_PRIVATE vma can be in both i_mmap tree and anon_vma
     90 	 * list, after a COW of one of the file pages.  A MAP_SHARED vma
     91 	 * can only be in the i_mmap tree.  An anonymous MAP_PRIVATE, stack
     92 	 * or brk vma (with NULL file) can only be in an anon_vma list.
     93 	 */
     94 	struct list_head anon_vma_node;	/* Serialized by anon_vma->lock */
     95 	struct anon_vma *anon_vma;	/* Serialized by page_table_lock */
     96 
     97 	/* Function pointers to deal with this struct. */
     98 	struct vm_operations_struct * vm_ops;
     99 
    100 	/* Information about our backing store: */
    101 	unsigned long vm_pgoff;		/* Offset (within vm_file) in PAGE_SIZE
    102 					   units, *not* PAGE_CACHE_SIZE */
    103 	struct file * vm_file;		/* File we map to (can be NULL). */
    104 	void * vm_private_data;		/* was vm_pte (shared mem) */
    105 	unsigned long vm_truncate_count;/* truncate_count or restart_addr */
    106 
    107 #ifndef CONFIG_MMU
    108 	atomic_t vm_usage;		/* refcount (VMAs shared if !MMU) */
    109 #endif
    110 #ifdef CONFIG_NUMA
    111 	struct mempolicy *vm_policy;	/* NUMA policy for the VMA */
    112 #endif
    113 };
    114 
    115 /*
    116  * This struct defines the per-mm list of VMAs for uClinux. If CONFIG_MMU is
    117  * disabled, then there's a single shared list of VMAs maintained by the
    118  * system, and mm's subscribe to these individually
    119  */
    120 struct vm_list_struct {
    121 	struct vm_list_struct	*next;
    122 	struct vm_area_struct	*vma;
    123 };
    124 
    125 #ifndef CONFIG_MMU
    126 extern struct rb_root nommu_vma_tree;
    127 extern struct rw_semaphore nommu_vma_sem;
    128 
    129 extern unsigned int kobjsize(const void *objp);
    130 #endif
    131 
    132 /*
    133  * vm_flags..
    134  */
    135 #define VM_READ		0x00000001	/* currently active flags */
    136 #define VM_WRITE	0x00000002
    137 #define VM_EXEC		0x00000004
    138 #define VM_SHARED	0x00000008
    139 
    140 /* mprotect() hardcodes VM_MAYREAD >> 4 == VM_READ, and so for r/w/x bits. */
    141 #define VM_MAYREAD	0x00000010	/* limits for mprotect() etc */
    142 #define VM_MAYWRITE	0x00000020
    143 #define VM_MAYEXEC	0x00000040
    144 #define VM_MAYSHARE	0x00000080
    145 
    146 #define VM_GROWSDOWN	0x00000100	/* general info on the segment */
    147 #define VM_GROWSUP	0x00000200
    148 #define VM_PFNMAP	0x00000400	/* Page-ranges managed without "struct page", just pure PFN */
    149 #define VM_DENYWRITE	0x00000800	/* ETXTBSY on write attempts.. */
    150 
    151 #define VM_EXECUTABLE	0x00001000
    152 #define VM_LOCKED	0x00002000
    153 #define VM_IO           0x00004000	/* Memory mapped I/O or similar */
    154 
    155 					/* Used by sys_madvise() */
    156 #define VM_SEQ_READ	0x00008000	/* App will access data sequentially */
    157 #define VM_RAND_READ	0x00010000	/* App will not benefit from clustered reads */
    158 
    159 #define VM_DONTCOPY	0x00020000      /* Do not copy this vma on fork */
    160 #define VM_DONTEXPAND	0x00040000	/* Cannot expand with mremap() */
    161 #define VM_RESERVED	0x00080000	/* Count as reserved_vm like IO */
    162 #define VM_ACCOUNT	0x00100000	/* Is a VM accounted object */
    163 #define VM_HUGETLB	0x00400000	/* Huge TLB Page VM */
    164 #define VM_NONLINEAR	0x00800000	/* Is non-linear (remap_file_pages) */
    165 #define VM_MAPPED_COPY	0x01000000	/* T if mapped copy of data (nommu mmap) */
    166 #define VM_INSERTPAGE	0x02000000	/* The vma has had "vm_insert_page()" done on it */
    167 
    168 #ifndef VM_STACK_DEFAULT_FLAGS		/* arch can override this */
    169 #define VM_STACK_DEFAULT_FLAGS VM_DATA_DEFAULT_FLAGS
    170 #endif
    171 
    172 #ifdef CONFIG_STACK_GROWSUP
    173 #define VM_STACK_FLAGS	(VM_GROWSUP | VM_STACK_DEFAULT_FLAGS | VM_ACCOUNT)
    174 #else
    175 #define VM_STACK_FLAGS	(VM_GROWSDOWN | VM_STACK_DEFAULT_FLAGS | VM_ACCOUNT)
    176 #endif
    177 
    178 #define VM_READHINTMASK			(VM_SEQ_READ | VM_RAND_READ)
    179 #define VM_ClearReadHint(v)		(v)->vm_flags &= ~VM_READHINTMASK
    180 #define VM_NormalReadHint(v)		(!((v)->vm_flags & VM_READHINTMASK))
    181 #define VM_SequentialReadHint(v)	((v)->vm_flags & VM_SEQ_READ)
    182 #define VM_RandomReadHint(v)		((v)->vm_flags & VM_RAND_READ)
    183 
    184 /*
    185  * mapping from the currently active vm_flags protection bits (the
    186  * low four bits) to a page protection mask..
    187  */
    188 extern pgprot_t protection_map[16];
    189 
    190 
    191 /*
    192  * These are the virtual MM functions - opening of an area, closing and
    193  * unmapping it (needed to keep files on disk up-to-date etc), pointer
    194  * to the functions called when a no-page or a wp-page exception occurs.
    195  */
    196 struct vm_operations_struct {
    197 	void (*open)(struct vm_area_struct * area);
    198 	void (*close)(struct vm_area_struct * area);
    199 	struct page * (*nopage)(struct vm_area_struct * area, unsigned long address, int *type);
    200 	int (*populate)(struct vm_area_struct * area, unsigned long address, unsigned long len, pgprot_t prot, unsigned long pgoff, int nonblock);
    201 
    202 	/* notification that a previously read-only page is about to become
    203 	 * writable, if an error is returned it will cause a SIGBUS */
    204 	int (*page_mkwrite)(struct vm_area_struct *vma, struct page *page);
    205 #ifdef CONFIG_NUMA
    206 	int (*set_policy)(struct vm_area_struct *vma, struct mempolicy *new);
    207 	struct mempolicy *(*get_policy)(struct vm_area_struct *vma,
    208 					unsigned long addr);
    209 	int (*migrate)(struct vm_area_struct *vma, const nodemask_t *from,
    210 		const nodemask_t *to, unsigned long flags);
    211 #endif
    212 };
    213 
    214 struct mmu_gather;
    215 struct inode;
    216 
    217 /*
    218  * Each physical page in the system has a struct page associated with
    219  * it to keep track of whatever it is we are using the page for at the
    220  * moment. Note that we have no way to track which tasks are using
    221  * a page.
    222  */
    223 struct page {
    224 	unsigned long flags;		/* Atomic flags, some possibly
    225 					 * updated asynchronously */
    226 	atomic_t _count;		/* Usage count, see below. */
    227 	atomic_t _mapcount;		/* Count of ptes mapped in mms,
    228 					 * to show when page is mapped
    229 					 * & limit reverse map searches.
    230 					 */
    231 	union {
    232 	    struct {
    233 		unsigned long private;		/* Mapping-private opaque data:
    234 					 	 * usually used for buffer_heads
    235 						 * if PagePrivate set; used for
    236 						 * swp_entry_t if PageSwapCache;
    237 						 * indicates order in the buddy
    238 						 * system if PG_buddy is set.
    239 						 */
    240 		struct address_space *mapping;	/* If low bit clear, points to
    241 						 * inode address_space, or NULL.
    242 						 * If page mapped as anonymous
    243 						 * memory, low bit is set, and
    244 						 * it points to anon_vma object:
    245 						 * see PAGE_MAPPING_ANON below.
    246 						 */
    247 	    };
    248 #if NR_CPUS >= CONFIG_SPLIT_PTLOCK_CPUS
    249 	    spinlock_t ptl;
    250 #endif
    251 	};
    252 	pgoff_t index;			/* Our offset within mapping. */
    253 	struct list_head lru;		/* Pageout list, eg. active_list
    254 					 * protected by zone->lru_lock !
    255 					 */
    256 	/*
    257 	 * On machines where all RAM is mapped into kernel address space,
    258 	 * we can simply calculate the virtual address. On machines with
    259 	 * highmem some memory is mapped into kernel virtual memory
    260 	 * dynamically, so we need a place to store that address.
    261 	 * Note that this field could be 16 bits on x86 ... ;)
    262 	 *
    263 	 * Architectures with slow multiplication can define
    264 	 * WANT_PAGE_VIRTUAL in asm/page.h
    265 	 */
    266 #if defined(WANT_PAGE_VIRTUAL)
    267 	void *virtual;			/* Kernel virtual address (NULL if
    268 					   not kmapped, ie. highmem) */
    269 #endif /* WANT_PAGE_VIRTUAL */
    270 };
    271 
    272 #define page_private(page)		((page)->private)
    273 #define set_page_private(page, v)	((page)->private = (v))
    274 
    275 /*
    276  * FIXME: take this include out, include page-flags.h in
    277  * files which need it (119 of them)
    278  */
    279 #include <linux/page-flags.h>
    280 
    281 /*
    282  * Methods to modify the page usage count.
    283  *
    284  * What counts for a page usage:
    285  * - cache mapping   (page->mapping)
    286  * - private data    (page->private)
    287  * - page mapped in a task's page tables, each mapping
    288  *   is counted separately
    289  *
    290  * Also, many kernel routines increase the page count before a critical
    291  * routine so they can be sure the page doesn't go away from under them.
    292  */
    293 
    294 /*
    295  * Drop a ref, return true if the logical refcount fell to zero (the page has
    296  * no users)
    297  */
    298 static inline int put_page_testzero(struct page *page)
    299 {
    300 	BUG_ON(atomic_read(&page->_count) == 0);
    301 	return atomic_dec_and_test(&page->_count);
    302 }
    303 
    304 /*
    305  * Try to grab a ref unless the page has a refcount of zero, return false if
    306  * that is the case.
    307  */
    308 static inline int get_page_unless_zero(struct page *page)
    309 {
    310 	return atomic_inc_not_zero(&page->_count);
    311 }
    312 
    313 extern void FASTCALL(__page_cache_release(struct page *));
    314 
    315 static inline int page_count(struct page *page)
    316 {
    317 	if (unlikely(PageCompound(page)))
    318 		page = (struct page *)page_private(page);
    319 	return atomic_read(&page->_count);
    320 }
    321 
    322 static inline void get_page(struct page *page)
    323 {
    324 	if (unlikely(PageCompound(page)))
    325 		page = (struct page *)page_private(page);
    326 	atomic_inc(&page->_count);
    327 }
    328 
    329 /*
    330  * Setup the page count before being freed into the page allocator for
    331  * the first time (boot or memory hotplug)
    332  */
    333 static inline void init_page_count(struct page *page)
    334 {
    335 	atomic_set(&page->_count, 1);
    336 }
    337 
    338 void put_page(struct page *page);
    339 void put_pages_list(struct list_head *pages);
    340 
    341 void split_page(struct page *page, unsigned int order);
    342 
    343 /*
    344  * Multiple processes may "see" the same page. E.g. for untouched
    345  * mappings of /dev/null, all processes see the same page full of
    346  * zeroes, and text pages of executables and shared libraries have
    347  * only one copy in memory, at most, normally.
    348  *
    349  * For the non-reserved pages, page_count(page) denotes a reference count.
    350  *   page_count() == 0 means the page is free. page->lru is then used for
    351  *   freelist management in the buddy allocator.
    352  *   page_count() == 1 means the page is used for exactly one purpose
    353  *   (e.g. a private data page of one process).
    354  *
    355  * A page may be used for kmalloc() or anyone else who does a
    356  * __get_free_page(). In this case the page_count() is at least 1, and
    357  * all other fields are unused but should be 0 or NULL. The
    358  * management of this page is the responsibility of the one who uses
    359  * it.
    360  *
    361  * The other pages (we may call them "process pages") are completely
    362  * managed by the Linux memory manager: I/O, buffers, swapping etc.
    363  * The following discussion applies only to them.
    364  *
    365  * A page may belong to an inode's memory mapping. In this case,
    366  * page->mapping is the pointer to the inode, and page->index is the
    367  * file offset of the page, in units of PAGE_CACHE_SIZE.
    368  *
    369  * A page contains an opaque `private' member, which belongs to the
    370  * page's address_space.  Usually, this is the address of a circular
    371  * list of the page's disk buffers.
    372  *
    373  * For pages belonging to inodes, the page_count() is the number of
    374  * attaches, plus 1 if `private' contains something, plus one for
    375  * the page cache itself.
    376  *
    377  * Instead of keeping dirty/clean pages in per address-space lists, we instead
    378  * now tag pages as dirty/under writeback in the radix tree.
    379  *
    380  * There is also a per-mapping radix tree mapping index to the page
    381  * in memory if present. The tree is rooted at mapping->root.
    382  *
    383  * All process pages can do I/O:
    384  * - inode pages may need to be read from disk,
    385  * - inode pages which have been modified and are MAP_SHARED may need
    386  *   to be written to disk,
    387  * - private pages which have been modified may need to be swapped out
    388  *   to swap space and (later) to be read back into memory.
    389  */
    390 
    391 /*
    392  * The zone field is never updated after free_area_init_core()
    393  * sets it, so none of the operations on it need to be atomic.
    394  */
    395 
    396 
    397 /*
    398  * page->flags layout:
    399  *
    400  * There are three possibilities for how page->flags get
    401  * laid out.  The first is for the normal case, without
    402  * sparsemem.  The second is for sparsemem when there is
    403  * plenty of space for node and section.  The last is when
    404  * we have run out of space and have to fall back to an
    405  * alternate (slower) way of determining the node.
    406  *
    407  *        No sparsemem: |       NODE     | ZONE | ... | FLAGS |
    408  * with space for node: | SECTION | NODE | ZONE | ... | FLAGS |
    409  *   no space for node: | SECTION |     ZONE    | ... | FLAGS |
    410  */
    411 #ifdef CONFIG_SPARSEMEM
    412 #define SECTIONS_WIDTH		SECTIONS_SHIFT
    413 #else
    414 #define SECTIONS_WIDTH		0
    415 #endif
    416 
    417 #define ZONES_WIDTH		ZONES_SHIFT
    418 
    419 #if SECTIONS_WIDTH+ZONES_WIDTH+NODES_SHIFT <= FLAGS_RESERVED
    420 #define NODES_WIDTH		NODES_SHIFT
    421 #else
    422 #define NODES_WIDTH		0
    423 #endif
    424 
    425 /* Page flags: | [SECTION] | [NODE] | ZONE | ... | FLAGS | */
    426 #define SECTIONS_PGOFF		((sizeof(unsigned long)*8) - SECTIONS_WIDTH)
    427 #define NODES_PGOFF		(SECTIONS_PGOFF - NODES_WIDTH)
    428 #define ZONES_PGOFF		(NODES_PGOFF - ZONES_WIDTH)
    429 
    430 /*
    431  * We are going to use the flags for the page to node mapping if its in
    432  * there.  This includes the case where there is no node, so it is implicit.
    433  */
    434 #define FLAGS_HAS_NODE		(NODES_WIDTH > 0 || NODES_SHIFT == 0)
    435 
    436 #ifndef PFN_SECTION_SHIFT
    437 #define PFN_SECTION_SHIFT 0
    438 #endif
    439 
    440 /*
    441  * Define the bit shifts to access each section.  For non-existant
    442  * sections we define the shift as 0; that plus a 0 mask ensures
    443  * the compiler will optimise away reference to them.
    444  */
    445 #define SECTIONS_PGSHIFT	(SECTIONS_PGOFF * (SECTIONS_WIDTH != 0))
    446 #define NODES_PGSHIFT		(NODES_PGOFF * (NODES_WIDTH != 0))
    447 #define ZONES_PGSHIFT		(ZONES_PGOFF * (ZONES_WIDTH != 0))
    448 
    449 /* NODE:ZONE or SECTION:ZONE is used to lookup the zone from a page. */
    450 #if FLAGS_HAS_NODE
    451 #define ZONETABLE_SHIFT		(NODES_SHIFT + ZONES_SHIFT)
    452 #else
    453 #define ZONETABLE_SHIFT		(SECTIONS_SHIFT + ZONES_SHIFT)
    454 #endif
    455 #define ZONETABLE_PGSHIFT	ZONES_PGSHIFT
    456 
    457 #if SECTIONS_WIDTH+NODES_WIDTH+ZONES_WIDTH > FLAGS_RESERVED
    458 #error SECTIONS_WIDTH+NODES_WIDTH+ZONES_WIDTH > FLAGS_RESERVED
    459 #endif
    460 
    461 #define ZONES_MASK		((1UL << ZONES_WIDTH) - 1)
    462 #define NODES_MASK		((1UL << NODES_WIDTH) - 1)
    463 #define SECTIONS_MASK		((1UL << SECTIONS_WIDTH) - 1)
    464 #define ZONETABLE_MASK		((1UL << ZONETABLE_SHIFT) - 1)
    465 
    466 static inline unsigned long page_zonenum(struct page *page)
    467 {
    468 	return (page->flags >> ZONES_PGSHIFT) & ZONES_MASK;
    469 }
    470 
    471 struct zone;
    472 extern struct zone *zone_table[];
    473 
    474 static inline int page_zone_id(struct page *page)
    475 {
    476 	return (page->flags >> ZONETABLE_PGSHIFT) & ZONETABLE_MASK;
    477 }
    478 static inline struct zone *page_zone(struct page *page)
    479 {
    480 	return zone_table[page_zone_id(page)];
    481 }
    482 
    483 static inline unsigned long page_to_nid(struct page *page)
    484 {
    485 	if (FLAGS_HAS_NODE)
    486 		return (page->flags >> NODES_PGSHIFT) & NODES_MASK;
    487 	else
    488 		return page_zone(page)->zone_pgdat->node_id;
    489 }
    490 static inline unsigned long page_to_section(struct page *page)
    491 {
    492 	return (page->flags >> SECTIONS_PGSHIFT) & SECTIONS_MASK;
    493 }
    494 
    495 static inline void set_page_zone(struct page *page, unsigned long zone)
    496 {
    497 	page->flags &= ~(ZONES_MASK << ZONES_PGSHIFT);
    498 	page->flags |= (zone & ZONES_MASK) << ZONES_PGSHIFT;
    499 }
    500 static inline void set_page_node(struct page *page, unsigned long node)
    501 {
    502 	page->flags &= ~(NODES_MASK << NODES_PGSHIFT);
    503 	page->flags |= (node & NODES_MASK) << NODES_PGSHIFT;
    504 }
    505 static inline void set_page_section(struct page *page, unsigned long section)
    506 {
    507 	page->flags &= ~(SECTIONS_MASK << SECTIONS_PGSHIFT);
    508 	page->flags |= (section & SECTIONS_MASK) << SECTIONS_PGSHIFT;
    509 }
    510 
    511 static inline void set_page_links(struct page *page, unsigned long zone,
    512 	unsigned long node, unsigned long pfn)
    513 {
    514 	set_page_zone(page, zone);
    515 	set_page_node(page, node);
    516 	set_page_section(page, pfn_to_section_nr(pfn));
    517 }
    518 
    519 /*
    520  * Some inline functions in vmstat.h depend on page_zone()
    521  */
    522 #include <linux/vmstat.h>
    523 
    524 #ifndef CONFIG_DISCONTIGMEM
    525 /* The array of struct pages - for discontigmem use pgdat->lmem_map */
    526 extern struct page *mem_map;
    527 #endif
    528 
    529 static __always_inline void *lowmem_page_address(struct page *page)
    530 {
    531 	return __va(page_to_pfn(page) << PAGE_SHIFT);
    532 }
    533 
    534 #if defined(CONFIG_HIGHMEM) && !defined(WANT_PAGE_VIRTUAL)
    535 #define HASHED_PAGE_VIRTUAL
    536 #endif
    537 
    538 #if defined(WANT_PAGE_VIRTUAL)
    539 #define page_address(page) ((page)->virtual)
    540 #define set_page_address(page, address)			\
    541 	do {						\
    542 		(page)->virtual = (address);		\
    543 	} while(0)
    544 #define page_address_init()  do { } while(0)
    545 #endif
    546 
    547 #if defined(HASHED_PAGE_VIRTUAL)
    548 void *page_address(struct page *page);
    549 void set_page_address(struct page *page, void *virtual);
    550 void page_address_init(void);
    551 #endif
    552 
    553 #if !defined(HASHED_PAGE_VIRTUAL) && !defined(WANT_PAGE_VIRTUAL)
    554 #define page_address(page) lowmem_page_address(page)
    555 #define set_page_address(page, address)  do { } while(0)
    556 #define page_address_init()  do { } while(0)
    557 #endif
    558 
    559 /*
    560  * On an anonymous page mapped into a user virtual memory area,
    561  * page->mapping points to its anon_vma, not to a struct address_space;
    562  * with the PAGE_MAPPING_ANON bit set to distinguish it.
    563  *
    564  * Please note that, confusingly, "page_mapping" refers to the inode
    565  * address_space which maps the page from disk; whereas "page_mapped"
    566  * refers to user virtual address space into which the page is mapped.
    567  */
    568 #define PAGE_MAPPING_ANON	1
    569 
    570 extern struct address_space swapper_space;
    571 static inline struct address_space *page_mapping(struct page *page)
    572 {
    573 	struct address_space *mapping = page->mapping;
    574 
    575 	if (unlikely(PageSwapCache(page)))
    576 		mapping = &swapper_space;
    577 	else if (unlikely((unsigned long)mapping & PAGE_MAPPING_ANON))
    578 		mapping = NULL;
    579 	return mapping;
    580 }
    581 
    582 static inline int PageAnon(struct page *page)
    583 {
    584 	return ((unsigned long)page->mapping & PAGE_MAPPING_ANON) != 0;
    585 }
    586 
    587 /*
    588  * Return the pagecache index of the passed page.  Regular pagecache pages
    589  * use ->index whereas swapcache pages use ->private
    590  */
    591 static inline pgoff_t page_index(struct page *page)
    592 {
    593 	if (unlikely(PageSwapCache(page)))
    594 		return page_private(page);
    595 	return page->index;
    596 }
    597 
    598 /*
    599  * The atomic page->_mapcount, like _count, starts from -1:
    600  * so that transitions both from it and to it can be tracked,
    601  * using atomic_inc_and_test and atomic_add_negative(-1).
    602  */
    603 static inline void reset_page_mapcount(struct page *page)
    604 {
    605 	atomic_set(&(page)->_mapcount, -1);
    606 }
    607 
    608 static inline int page_mapcount(struct page *page)
    609 {
    610 	return atomic_read(&(page)->_mapcount) + 1;
    611 }
    612 
    613 /*
    614  * Return true if this page is mapped into pagetables.
    615  */
    616 static inline int page_mapped(struct page *page)
    617 {
    618 	return atomic_read(&(page)->_mapcount) >= 0;
    619 }
    620 
    621 /*
    622  * Error return values for the *_nopage functions
    623  */
    624 #define NOPAGE_SIGBUS	(NULL)
    625 #define NOPAGE_OOM	((struct page *) (-1))
    626 
    627 /*
    628  * Different kinds of faults, as returned by handle_mm_fault().
    629  * Used to decide whether a process gets delivered SIGBUS or
    630  * just gets major/minor fault counters bumped up.
    631  */
    632 #define VM_FAULT_OOM	0x00
    633 #define VM_FAULT_SIGBUS	0x01
    634 #define VM_FAULT_MINOR	0x02
    635 #define VM_FAULT_MAJOR	0x03
    636 
    637 /*
    638  * Special case for get_user_pages.
    639  * Must be in a distinct bit from the above VM_FAULT_ flags.
    640  */
    641 #define VM_FAULT_WRITE	0x10
    642 
    643 #define offset_in_page(p)	((unsigned long)(p) & ~PAGE_MASK)
    644 
    645 extern void show_free_areas(void);
    646 
    647 #ifdef CONFIG_SHMEM
    648 struct page *shmem_nopage(struct vm_area_struct *vma,
    649 			unsigned long address, int *type);
    650 int shmem_set_policy(struct vm_area_struct *vma, struct mempolicy *new);
    651 struct mempolicy *shmem_get_policy(struct vm_area_struct *vma,
    652 					unsigned long addr);
    653 int shmem_lock(struct file *file, int lock, struct user_struct *user);
    654 #else
    655 #define shmem_nopage filemap_nopage
    656 
    657 static inline int shmem_lock(struct file *file, int lock,
    658 			     struct user_struct *user)
    659 {
    660 	return 0;
    661 }
    662 
    663 static inline int shmem_set_policy(struct vm_area_struct *vma,
    664 				   struct mempolicy *new)
    665 {
    666 	return 0;
    667 }
    668 
    669 static inline struct mempolicy *shmem_get_policy(struct vm_area_struct *vma,
    670 						 unsigned long addr)
    671 {
    672 	return NULL;
    673 }
    674 #endif
    675 struct file *shmem_file_setup(char *name, loff_t size, unsigned long flags);
    676 extern int shmem_mmap(struct file *file, struct vm_area_struct *vma);
    677 
    678 int shmem_zero_setup(struct vm_area_struct *);
    679 
    680 #ifndef CONFIG_MMU
    681 extern unsigned long shmem_get_unmapped_area(struct file *file,
    682 					     unsigned long addr,
    683 					     unsigned long len,
    684 					     unsigned long pgoff,
    685 					     unsigned long flags);
    686 #endif
    687 
    688 static inline int can_do_mlock(void)
    689 {
    690 	if (capable(CAP_IPC_LOCK))
    691 		return 1;
    692 	if (current->signal->rlim[RLIMIT_MEMLOCK].rlim_cur != 0)
    693 		return 1;
    694 	return 0;
    695 }
    696 extern int user_shm_lock(size_t, struct user_struct *);
    697 extern void user_shm_unlock(size_t, struct user_struct *);
    698 
    699 /*
    700  * Parameter block passed down to zap_pte_range in exceptional cases.
    701  */
    702 struct zap_details {
    703 	struct vm_area_struct *nonlinear_vma;	/* Check page->index if set */
    704 	struct address_space *check_mapping;	/* Check page->mapping if set */
    705 	pgoff_t	first_index;			/* Lowest page->index to unmap */
    706 	pgoff_t last_index;			/* Highest page->index to unmap */
    707 	spinlock_t *i_mmap_lock;		/* For unmap_mapping_range: */
    708 	unsigned long truncate_count;		/* Compare vm_truncate_count */
    709 };
    710 
    711 struct page *vm_normal_page(struct vm_area_struct *, unsigned long, pte_t);
    712 unsigned long zap_page_range(struct vm_area_struct *vma, unsigned long address,
    713 		unsigned long size, struct zap_details *);
    714 unsigned long unmap_vmas(struct mmu_gather **tlb,
    715 		struct vm_area_struct *start_vma, unsigned long start_addr,
    716 		unsigned long end_addr, unsigned long *nr_accounted,
    717 		struct zap_details *);
    718 void free_pgd_range(struct mmu_gather **tlb, unsigned long addr,
    719 		unsigned long end, unsigned long floor, unsigned long ceiling);
    720 void free_pgtables(struct mmu_gather **tlb, struct vm_area_struct *start_vma,
    721 		unsigned long floor, unsigned long ceiling);
    722 int copy_page_range(struct mm_struct *dst, struct mm_struct *src,
    723 			struct vm_area_struct *vma);
    724 int zeromap_page_range(struct vm_area_struct *vma, unsigned long from,
    725 			unsigned long size, pgprot_t prot);
    726 void unmap_mapping_range(struct address_space *mapping,
    727 		loff_t const holebegin, loff_t const holelen, int even_cows);
    728 
    729 static inline void unmap_shared_mapping_range(struct address_space *mapping,
    730 		loff_t const holebegin, loff_t const holelen)
    731 {
    732 	unmap_mapping_range(mapping, holebegin, holelen, 0);
    733 }
    734 
    735 extern int vmtruncate(struct inode * inode, loff_t offset);
    736 extern int vmtruncate_range(struct inode * inode, loff_t offset, loff_t end);
    737 extern int install_page(struct mm_struct *mm, struct vm_area_struct *vma, unsigned long addr, struct page *page, pgprot_t prot);
    738 extern int install_file_pte(struct mm_struct *mm, struct vm_area_struct *vma, unsigned long addr, unsigned long pgoff, pgprot_t prot);
    739 
    740 #ifdef CONFIG_MMU
    741 extern int __handle_mm_fault(struct mm_struct *mm,struct vm_area_struct *vma,
    742 			unsigned long address, int write_access);
    743 
    744 static inline int handle_mm_fault(struct mm_struct *mm,
    745 			struct vm_area_struct *vma, unsigned long address,
    746 			int write_access)
    747 {
    748 	return __handle_mm_fault(mm, vma, address, write_access) &
    749 				(~VM_FAULT_WRITE);
    750 }
    751 #else
    752 static inline int handle_mm_fault(struct mm_struct *mm,
    753 			struct vm_area_struct *vma, unsigned long address,
    754 			int write_access)
    755 {
    756 	/* should never happen if there's no MMU */
    757 	BUG();
    758 	return VM_FAULT_SIGBUS;
    759 }
    760 #endif
    761 
    762 extern int make_pages_present(unsigned long addr, unsigned long end);
    763 extern int access_process_vm(struct task_struct *tsk, unsigned long addr, void *buf, int len, int write);
    764 void install_arg_page(struct vm_area_struct *, struct page *, unsigned long);
    765 
    766 int get_user_pages(struct task_struct *tsk, struct mm_struct *mm, unsigned long start,
    767 		int len, int write, int force, struct page **pages, struct vm_area_struct **vmas);
    768 void print_bad_pte(struct vm_area_struct *, pte_t, unsigned long);
    769 
    770 int __set_page_dirty_buffers(struct page *page);
    771 int __set_page_dirty_nobuffers(struct page *page);
    772 int redirty_page_for_writepage(struct writeback_control *wbc,
    773 				struct page *page);
    774 int FASTCALL(set_page_dirty(struct page *page));
    775 int set_page_dirty_lock(struct page *page);
    776 int clear_page_dirty_for_io(struct page *page);
    777 
    778 extern unsigned long do_mremap(unsigned long addr,
    779 			       unsigned long old_len, unsigned long new_len,
    780 			       unsigned long flags, unsigned long new_addr);
    781 
    782 /*
    783  * Prototype to add a shrinker callback for ageable caches.
    784  *
    785  * These functions are passed a count `nr_to_scan' and a gfpmask.  They should
    786  * scan `nr_to_scan' objects, attempting to free them.
    787  *
    788  * The callback must return the number of objects which remain in the cache.
    789  *
    790  * The callback will be passed nr_to_scan == 0 when the VM is querying the
    791  * cache size, so a fastpath for that case is appropriate.
    792  */
    793 typedef int (*shrinker_t)(int nr_to_scan, gfp_t gfp_mask);
    794 
    795 /*
    796  * Add an aging callback.  The int is the number of 'seeks' it takes
    797  * to recreate one of the objects that these functions age.
    798  */
    799 
    800 #define DEFAULT_SEEKS 2
    801 struct shrinker;
    802 extern struct shrinker *set_shrinker(int, shrinker_t);
    803 extern void remove_shrinker(struct shrinker *shrinker);
    804 
    805 extern pte_t *FASTCALL(get_locked_pte(struct mm_struct *mm, unsigned long addr, spinlock_t **ptl));
    806 
    807 int __pud_alloc(struct mm_struct *mm, pgd_t *pgd, unsigned long address);
    808 int __pmd_alloc(struct mm_struct *mm, pud_t *pud, unsigned long address);
    809 int __pte_alloc(struct mm_struct *mm, pmd_t *pmd, unsigned long address);
    810 int __pte_alloc_kernel(pmd_t *pmd, unsigned long address);
    811 
    812 /*
    813  * The following ifdef needed to get the 4level-fixup.h header to work.
    814  * Remove it when 4level-fixup.h has been removed.
    815  */
    816 #if defined(CONFIG_MMU) && !defined(__ARCH_HAS_4LEVEL_HACK)
    817 static inline pud_t *pud_alloc(struct mm_struct *mm, pgd_t *pgd, unsigned long address)
    818 {
    819 	return (unlikely(pgd_none(*pgd)) && __pud_alloc(mm, pgd, address))?
    820 		NULL: pud_offset(pgd, address);
    821 }
    822 
    823 static inline pmd_t *pmd_alloc(struct mm_struct *mm, pud_t *pud, unsigned long address)
    824 {
    825 	return (unlikely(pud_none(*pud)) && __pmd_alloc(mm, pud, address))?
    826 		NULL: pmd_offset(pud, address);
    827 }
    828 #endif /* CONFIG_MMU && !__ARCH_HAS_4LEVEL_HACK */
    829 
    830 #if NR_CPUS >= CONFIG_SPLIT_PTLOCK_CPUS
    831 /*
    832  * We tuck a spinlock to guard each pagetable page into its struct page,
    833  * at page->private, with BUILD_BUG_ON to make sure that this will not
    834  * overflow into the next struct page (as it might with DEBUG_SPINLOCK).
    835  * When freeing, reset page->mapping so free_pages_check won't complain.
    836  */
    837 #define __pte_lockptr(page)	&((page)->ptl)
    838 #define pte_lock_init(_page)	do {					\
    839 	spin_lock_init(__pte_lockptr(_page));				\
    840 } while (0)
    841 #define pte_lock_deinit(page)	((page)->mapping = NULL)
    842 #define pte_lockptr(mm, pmd)	({(void)(mm); __pte_lockptr(pmd_page(*(pmd)));})
    843 #else
    844 /*
    845  * We use mm->page_table_lock to guard all pagetable pages of the mm.
    846  */
    847 #define pte_lock_init(page)	do {} while (0)
    848 #define pte_lock_deinit(page)	do {} while (0)
    849 #define pte_lockptr(mm, pmd)	({(void)(pmd); &(mm)->page_table_lock;})
    850 #endif /* NR_CPUS < CONFIG_SPLIT_PTLOCK_CPUS */
    851 
    852 #define pte_offset_map_lock(mm, pmd, address, ptlp)	\
    853 ({							\
    854 	spinlock_t *__ptl = pte_lockptr(mm, pmd);	\
    855 	pte_t *__pte = pte_offset_map(pmd, address);	\
    856 	*(ptlp) = __ptl;				\
    857 	spin_lock(__ptl);				\
    858 	__pte;						\
    859 })
    860 
    861 #define pte_unmap_unlock(pte, ptl)	do {		\
    862 	spin_unlock(ptl);				\
    863 	pte_unmap(pte);					\
    864 } while (0)
    865 
    866 #define pte_alloc_map(mm, pmd, address)			\
    867 	((unlikely(!pmd_present(*(pmd))) && __pte_alloc(mm, pmd, address))? \
    868 		NULL: pte_offset_map(pmd, address))
    869 
    870 #define pte_alloc_map_lock(mm, pmd, address, ptlp)	\
    871 	((unlikely(!pmd_present(*(pmd))) && __pte_alloc(mm, pmd, address))? \
    872 		NULL: pte_offset_map_lock(mm, pmd, address, ptlp))
    873 
    874 #define pte_alloc_kernel(pmd, address)			\
    875 	((unlikely(!pmd_present(*(pmd))) && __pte_alloc_kernel(pmd, address))? \
    876 		NULL: pte_offset_kernel(pmd, address))
    877 
    878 extern void free_area_init(unsigned long * zones_size);
    879 extern void free_area_init_node(int nid, pg_data_t *pgdat,
    880 	unsigned long * zones_size, unsigned long zone_start_pfn,
    881 	unsigned long *zholes_size);
    882 extern void memmap_init_zone(unsigned long, int, unsigned long, unsigned long);
    883 extern void setup_per_zone_pages_min(void);
    884 extern void mem_init(void);
    885 extern void show_mem(void);
    886 extern void si_meminfo(struct sysinfo * val);
    887 extern void si_meminfo_node(struct sysinfo *val, int nid);
    888 
    889 #ifdef CONFIG_NUMA
    890 extern void setup_per_cpu_pageset(void);
    891 #else
    892 static inline void setup_per_cpu_pageset(void) {}
    893 #endif
    894 
    895 /* prio_tree.c */
    896 void vma_prio_tree_add(struct vm_area_struct *, struct vm_area_struct *old);
    897 void vma_prio_tree_insert(struct vm_area_struct *, struct prio_tree_root *);
    898 void vma_prio_tree_remove(struct vm_area_struct *, struct prio_tree_root *);
    899 struct vm_area_struct *vma_prio_tree_next(struct vm_area_struct *vma,
    900 	struct prio_tree_iter *iter);
    901 
    902 #define vma_prio_tree_foreach(vma, iter, root, begin, end)	\
    903 	for (prio_tree_iter_init(iter, root, begin, end), vma = NULL;	\
    904 		(vma = vma_prio_tree_next(vma, iter)); )
    905 
    906 static inline void vma_nonlinear_insert(struct vm_area_struct *vma,
    907 					struct list_head *list)
    908 {
    909 	vma->shared.vm_set.parent = NULL;
    910 	list_add_tail(&vma->shared.vm_set.list, list);
    911 }
    912 
    913 /* mmap.c */
    914 extern int __vm_enough_memory(long pages, int cap_sys_admin);
    915 extern void vma_adjust(struct vm_area_struct *vma, unsigned long start,
    916 	unsigned long end, pgoff_t pgoff, struct vm_area_struct *insert);
    917 extern struct vm_area_struct *vma_merge(struct mm_struct *,
    918 	struct vm_area_struct *prev, unsigned long addr, unsigned long end,
    919 	unsigned long vm_flags, struct anon_vma *, struct file *, pgoff_t,
    920 	struct mempolicy *);
    921 extern struct anon_vma *find_mergeable_anon_vma(struct vm_area_struct *);
    922 extern int split_vma(struct mm_struct *,
    923 	struct vm_area_struct *, unsigned long addr, int new_below);
    924 extern int insert_vm_struct(struct mm_struct *, struct vm_area_struct *);
    925 extern void __vma_link_rb(struct mm_struct *, struct vm_area_struct *,
    926 	struct rb_node **, struct rb_node *);
    927 extern void unlink_file_vma(struct vm_area_struct *);
    928 extern struct vm_area_struct *copy_vma(struct vm_area_struct **,
    929 	unsigned long addr, unsigned long len, pgoff_t pgoff);
    930 extern void exit_mmap(struct mm_struct *);
    931 extern int may_expand_vm(struct mm_struct *mm, unsigned long npages);
    932 
    933 extern unsigned long get_unmapped_area(struct file *, unsigned long, unsigned long, unsigned long, unsigned long);
    934 
    935 extern unsigned long do_mmap_pgoff(struct file *file, unsigned long addr,
    936 	unsigned long len, unsigned long prot,
    937 	unsigned long flag, unsigned long pgoff);
    938 
    939 static inline unsigned long do_mmap(struct file *file, unsigned long addr,
    940 	unsigned long len, unsigned long prot,
    941 	unsigned long flag, unsigned long offset)
    942 {
    943 	unsigned long ret = -EINVAL;
    944 	if ((offset + PAGE_ALIGN(len)) < offset)
    945 		goto out;
    946 	if (!(offset & ~PAGE_MASK))
    947 		ret = do_mmap_pgoff(file, addr, len, prot, flag, offset >> PAGE_SHIFT);
    948 out:
    949 	return ret;
    950 }
    951 
    952 extern int do_munmap(struct mm_struct *, unsigned long, size_t);
    953 
    954 extern unsigned long do_brk(unsigned long, unsigned long);
    955 
    956 /* filemap.c */
    957 extern unsigned long page_unuse(struct page *);
    958 extern void truncate_inode_pages(struct address_space *, loff_t);
    959 extern void truncate_inode_pages_range(struct address_space *,
    960 				       loff_t lstart, loff_t lend);
    961 
    962 /* generic vm_area_ops exported for stackable file systems */
    963 extern struct page *filemap_nopage(struct vm_area_struct *, unsigned long, int *);
    964 extern int filemap_populate(struct vm_area_struct *, unsigned long,
    965 		unsigned long, pgprot_t, unsigned long, int);
    966 
    967 /* mm/page-writeback.c */
    968 int write_one_page(struct page *page, int wait);
    969 
    970 /* readahead.c */
    971 #define VM_MAX_READAHEAD	128	/* kbytes */
    972 #define VM_MIN_READAHEAD	16	/* kbytes (includes current page) */
    973 #define VM_MAX_CACHE_HIT    	256	/* max pages in a row in cache before
    974 					 * turning readahead off */
    975 
    976 int do_page_cache_readahead(struct address_space *mapping, struct file *filp,
    977 			pgoff_t offset, unsigned long nr_to_read);
    978 int force_page_cache_readahead(struct address_space *mapping, struct file *filp,
    979 			pgoff_t offset, unsigned long nr_to_read);
    980 unsigned long page_cache_readahead(struct address_space *mapping,
    981 			  struct file_ra_state *ra,
    982 			  struct file *filp,
    983 			  pgoff_t offset,
    984 			  unsigned long size);
    985 void handle_ra_miss(struct address_space *mapping,
    986 		    struct file_ra_state *ra, pgoff_t offset);
    987 unsigned long max_sane_readahead(unsigned long nr);
    988 
    989 /* Do stack extension */
    990 extern int expand_stack(struct vm_area_struct *vma, unsigned long address);
    991 #ifdef CONFIG_IA64
    992 extern int expand_upwards(struct vm_area_struct *vma, unsigned long address);
    993 #endif
    994 
    995 /* Look up the first VMA which satisfies  addr < vm_end,  NULL if none. */
    996 extern struct vm_area_struct * find_vma(struct mm_struct * mm, unsigned long addr);
    997 extern struct vm_area_struct * find_vma_prev(struct mm_struct * mm, unsigned long addr,
    998 					     struct vm_area_struct **pprev);
    999 
   1000 /* Look up the first VMA which intersects the interval start_addr..end_addr-1,
   1001    NULL if none.  Assume start_addr < end_addr. */
   1002 static inline struct vm_area_struct * find_vma_intersection(struct mm_struct * mm, unsigned long start_addr, unsigned long end_addr)
   1003 {
   1004 	struct vm_area_struct * vma = find_vma(mm,start_addr);
   1005 
   1006 	if (vma && end_addr <= vma->vm_start)
   1007 		vma = NULL;
   1008 	return vma;
   1009 }
   1010 
   1011 static inline unsigned long vma_pages(struct vm_area_struct *vma)
   1012 {
   1013 	return (vma->vm_end - vma->vm_start) >> PAGE_SHIFT;
   1014 }
   1015 
   1016 struct vm_area_struct *find_extend_vma(struct mm_struct *, unsigned long addr);
   1017 struct page *vmalloc_to_page(void *addr);
   1018 unsigned long vmalloc_to_pfn(void *addr);
   1019 int remap_pfn_range(struct vm_area_struct *, unsigned long addr,
   1020 			unsigned long pfn, unsigned long size, pgprot_t);
   1021 int vm_insert_page(struct vm_area_struct *, unsigned long addr, struct page *);
   1022 
   1023 struct page *follow_page(struct vm_area_struct *, unsigned long address,
   1024 			unsigned int foll_flags);
   1025 #define FOLL_WRITE	0x01	/* check pte is writable */
   1026 #define FOLL_TOUCH	0x02	/* mark page accessed */
   1027 #define FOLL_GET	0x04	/* do get_page on page */
   1028 #define FOLL_ANON	0x08	/* give ZERO_PAGE if no pgtable */
   1029 
   1030 #ifdef CONFIG_PROC_FS
   1031 void vm_stat_account(struct mm_struct *, unsigned long, struct file *, long);
   1032 #else
   1033 static inline void vm_stat_account(struct mm_struct *mm,
   1034 			unsigned long flags, struct file *file, long pages)
   1035 {
   1036 }
   1037 #endif /* CONFIG_PROC_FS */
   1038 
   1039 #ifndef CONFIG_DEBUG_PAGEALLOC
   1040 static inline void
   1041 kernel_map_pages(struct page *page, int numpages, int enable)
   1042 {
   1043 	if (!PageHighMem(page) && !enable)
   1044 		debug_check_no_locks_freed(page_address(page),
   1045 					   numpages * PAGE_SIZE);
   1046 }
   1047 #endif
   1048 
   1049 extern struct vm_area_struct *get_gate_vma(struct task_struct *tsk);
   1050 #ifdef	__HAVE_ARCH_GATE_AREA
   1051 int in_gate_area_no_task(unsigned long addr);
   1052 int in_gate_area(struct task_struct *task, unsigned long addr);
   1053 #else
   1054 int in_gate_area_no_task(unsigned long addr);
   1055 #define in_gate_area(task, addr) ({(void)task; in_gate_area_no_task(addr);})
   1056 #endif	/* __HAVE_ARCH_GATE_AREA */
   1057 
   1058 /* /proc/<pid>/oom_adj set to -17 protects from the oom-killer */
   1059 #define OOM_DISABLE -17
   1060 
   1061 int drop_caches_sysctl_handler(struct ctl_table *, int, struct file *,
   1062 					void __user *, size_t *, loff_t *);
   1063 unsigned long shrink_slab(unsigned long scanned, gfp_t gfp_mask,
   1064 			unsigned long lru_pages);
   1065 void drop_pagecache(void);
   1066 void drop_slab(void);
   1067 
   1068 #ifndef CONFIG_MMU
   1069 #define randomize_va_space 0
   1070 #else
   1071 extern int randomize_va_space;
   1072 #endif
   1073 
   1074 const char *arch_vma_name(struct vm_area_struct *vma);
   1075 
   1076 #endif /* __KERNEL__ */
   1077 #endif /* _LINUX_MM_H */
   1078