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/* SPDX-License-Identifier: GPL-2.0 */
#ifndef _LINUX_PAGEMAP_H
#define _LINUX_PAGEMAP_H
/*
* Copyright 1995 Linus Torvalds
*/
#include <linux/mm.h>
#include <linux/fs.h>
#include <linux/list.h>
#include <linux/highmem.h>
#include <linux/compiler.h>
#include <linux/uaccess.h>
#include <linux/gfp.h>
#include <linux/bitops.h>
#include <linux/hardirq.h> /* for in_interrupt() */
#include <linux/hugetlb_inline.h>
struct folio_batch;
unsigned long invalidate_mapping_pages(struct address_space *mapping,
pgoff_t start, pgoff_t end);
static inline void invalidate_remote_inode(struct inode *inode)
{
if (S_ISREG(inode->i_mode) || S_ISDIR(inode->i_mode) ||
S_ISLNK(inode->i_mode))
invalidate_mapping_pages(inode->i_mapping, 0, -1);
}
int invalidate_inode_pages2(struct address_space *mapping);
int invalidate_inode_pages2_range(struct address_space *mapping,
pgoff_t start, pgoff_t end);
int kiocb_invalidate_pages(struct kiocb *iocb, size_t count);
void kiocb_invalidate_post_direct_write(struct kiocb *iocb, size_t count);
int write_inode_now(struct inode *, int sync);
int filemap_fdatawrite(struct address_space *);
int filemap_flush(struct address_space *);
int filemap_fdatawait_keep_errors(struct address_space *mapping);
int filemap_fdatawait_range(struct address_space *, loff_t lstart, loff_t lend);
int filemap_fdatawait_range_keep_errors(struct address_space *mapping,
loff_t start_byte, loff_t end_byte);
int filemap_invalidate_inode(struct inode *inode, bool flush,
loff_t start, loff_t end);
static inline int filemap_fdatawait(struct address_space *mapping)
{
return filemap_fdatawait_range(mapping, 0, LLONG_MAX);
}
bool filemap_range_has_page(struct address_space *, loff_t lstart, loff_t lend);
int filemap_write_and_wait_range(struct address_space *mapping,
loff_t lstart, loff_t lend);
int __filemap_fdatawrite_range(struct address_space *mapping,
loff_t start, loff_t end, int sync_mode);
int filemap_fdatawrite_range(struct address_space *mapping,
loff_t start, loff_t end);
int filemap_check_errors(struct address_space *mapping);
void __filemap_set_wb_err(struct address_space *mapping, int err);
int filemap_fdatawrite_wbc(struct address_space *mapping,
struct writeback_control *wbc);
int kiocb_write_and_wait(struct kiocb *iocb, size_t count);
static inline int filemap_write_and_wait(struct address_space *mapping)
{
return filemap_write_and_wait_range(mapping, 0, LLONG_MAX);
}
/**
* filemap_set_wb_err - set a writeback error on an address_space
* @mapping: mapping in which to set writeback error
* @err: error to be set in mapping
*
* When writeback fails in some way, we must record that error so that
* userspace can be informed when fsync and the like are called. We endeavor
* to report errors on any file that was open at the time of the error. Some
* internal callers also need to know when writeback errors have occurred.
*
* When a writeback error occurs, most filesystems will want to call
* filemap_set_wb_err to record the error in the mapping so that it will be
* automatically reported whenever fsync is called on the file.
*/
static inline void filemap_set_wb_err(struct address_space *mapping, int err)
{
/* Fastpath for common case of no error */
if (unlikely(err))
__filemap_set_wb_err(mapping, err);
}
/**
* filemap_check_wb_err - has an error occurred since the mark was sampled?
* @mapping: mapping to check for writeback errors
* @since: previously-sampled errseq_t
*
* Grab the errseq_t value from the mapping, and see if it has changed "since"
* the given value was sampled.
*
* If it has then report the latest error set, otherwise return 0.
*/
static inline int filemap_check_wb_err(struct address_space *mapping,
errseq_t since)
{
return errseq_check(&mapping->wb_err, since);
}
/**
* filemap_sample_wb_err - sample the current errseq_t to test for later errors
* @mapping: mapping to be sampled
*
* Writeback errors are always reported relative to a particular sample point
* in the past. This function provides those sample points.
*/
static inline errseq_t filemap_sample_wb_err(struct address_space *mapping)
{
return errseq_sample(&mapping->wb_err);
}
/**
* file_sample_sb_err - sample the current errseq_t to test for later errors
* @file: file pointer to be sampled
*
* Grab the most current superblock-level errseq_t value for the given
* struct file.
*/
static inline errseq_t file_sample_sb_err(struct file *file)
{
return errseq_sample(&file->f_path.dentry->d_sb->s_wb_err);
}
/*
* Flush file data before changing attributes. Caller must hold any locks
* required to prevent further writes to this file until we're done setting
* flags.
*/
static inline int inode_drain_writes(struct inode *inode)
{
inode_dio_wait(inode);
return filemap_write_and_wait(inode->i_mapping);
}
static inline bool mapping_empty(struct address_space *mapping)
{
return xa_empty(&mapping->i_pages);
}
/*
* mapping_shrinkable - test if page cache state allows inode reclaim
* @mapping: the page cache mapping
*
* This checks the mapping's cache state for the pupose of inode
* reclaim and LRU management.
*
* The caller is expected to hold the i_lock, but is not required to
* hold the i_pages lock, which usually protects cache state. That's
* because the i_lock and the list_lru lock that protect the inode and
* its LRU state don't nest inside the irq-safe i_pages lock.
*
* Cache deletions are performed under the i_lock, which ensures that
* when an inode goes empty, it will reliably get queued on the LRU.
*
* Cache additions do not acquire the i_lock and may race with this
* check, in which case we'll report the inode as shrinkable when it
* has cache pages. This is okay: the shrinker also checks the
* refcount and the referenced bit, which will be elevated or set in
* the process of adding new cache pages to an inode.
*/
static inline bool mapping_shrinkable(struct address_space *mapping)
{
void *head;
/*
* On highmem systems, there could be lowmem pressure from the
* inodes before there is highmem pressure from the page
* cache. Make inodes shrinkable regardless of cache state.
*/
if (IS_ENABLED(CONFIG_HIGHMEM))
return true;
/* Cache completely empty? Shrink away. */
head = rcu_access_pointer(mapping->i_pages.xa_head);
if (!head)
return true;
/*
* The xarray stores single offset-0 entries directly in the
* head pointer, which allows non-resident page cache entries
* to escape the shadow shrinker's list of xarray nodes. The
* inode shrinker needs to pick them up under memory pressure.
*/
if (!xa_is_node(head) && xa_is_value(head))
return true;
return false;
}
/*
* Bits in mapping->flags.
*/
enum mapping_flags {
AS_EIO = 0, /* IO error on async write */
AS_ENOSPC = 1, /* ENOSPC on async write */
AS_MM_ALL_LOCKS = 2, /* under mm_take_all_locks() */
AS_UNEVICTABLE = 3, /* e.g., ramdisk, SHM_LOCK */
AS_EXITING = 4, /* final truncate in progress */
/* writeback related tags are not used */
AS_NO_WRITEBACK_TAGS = 5,
AS_LARGE_FOLIO_SUPPORT = 6,
AS_RELEASE_ALWAYS, /* Call ->release_folio(), even if no private data */
AS_STABLE_WRITES, /* must wait for writeback before modifying
folio contents */
AS_UNMOVABLE, /* The mapping cannot be moved, ever */
};
/**
* mapping_set_error - record a writeback error in the address_space
* @mapping: the mapping in which an error should be set
* @error: the error to set in the mapping
*
* When writeback fails in some way, we must record that error so that
* userspace can be informed when fsync and the like are called. We endeavor
* to report errors on any file that was open at the time of the error. Some
* internal callers also need to know when writeback errors have occurred.
*
* When a writeback error occurs, most filesystems will want to call
* mapping_set_error to record the error in the mapping so that it can be
* reported when the application calls fsync(2).
*/
static inline void mapping_set_error(struct address_space *mapping, int error)
{
if (likely(!error))
return;
/* Record in wb_err for checkers using errseq_t based tracking */
__filemap_set_wb_err(mapping, error);
/* Record it in superblock */
if (mapping->host)
errseq_set(&mapping->host->i_sb->s_wb_err, error);
/* Record it in flags for now, for legacy callers */
if (error == -ENOSPC)
set_bit(AS_ENOSPC, &mapping->flags);
else
set_bit(AS_EIO, &mapping->flags);
}
static inline void mapping_set_unevictable(struct address_space *mapping)
{
set_bit(AS_UNEVICTABLE, &mapping->flags);
}
static inline void mapping_clear_unevictable(struct address_space *mapping)
{
clear_bit(AS_UNEVICTABLE, &mapping->flags);
}
static inline bool mapping_unevictable(struct address_space *mapping)
{
return mapping && test_bit(AS_UNEVICTABLE, &mapping->flags);
}
static inline void mapping_set_exiting(struct address_space *mapping)
{
set_bit(AS_EXITING, &mapping->flags);
}
static inline int mapping_exiting(struct address_space *mapping)
{
return test_bit(AS_EXITING, &mapping->flags);
}
static inline void mapping_set_no_writeback_tags(struct address_space *mapping)
{
set_bit(AS_NO_WRITEBACK_TAGS, &mapping->flags);
}
static inline int mapping_use_writeback_tags(struct address_space *mapping)
{
return !test_bit(AS_NO_WRITEBACK_TAGS, &mapping->flags);
}
static inline bool mapping_release_always(const struct address_space *mapping)
{
return test_bit(AS_RELEASE_ALWAYS, &mapping->flags);
}
static inline void mapping_set_release_always(struct address_space *mapping)
{
set_bit(AS_RELEASE_ALWAYS, &mapping->flags);
}
static inline void mapping_clear_release_always(struct address_space *mapping)
{
clear_bit(AS_RELEASE_ALWAYS, &mapping->flags);
}
static inline bool mapping_stable_writes(const struct address_space *mapping)
{
return test_bit(AS_STABLE_WRITES, &mapping->flags);
}
static inline void mapping_set_stable_writes(struct address_space *mapping)
{
set_bit(AS_STABLE_WRITES, &mapping->flags);
}
static inline void mapping_clear_stable_writes(struct address_space *mapping)
{
clear_bit(AS_STABLE_WRITES, &mapping->flags);
}
static inline void mapping_set_unmovable(struct address_space *mapping)
{
/*
* It's expected unmovable mappings are also unevictable. Compaction
* migrate scanner (isolate_migratepages_block()) relies on this to
* reduce page locking.
*/
set_bit(AS_UNEVICTABLE, &mapping->flags);
set_bit(AS_UNMOVABLE, &mapping->flags);
}
static inline bool mapping_unmovable(struct address_space *mapping)
{
return test_bit(AS_UNMOVABLE, &mapping->flags);
}
static inline gfp_t mapping_gfp_mask(struct address_space * mapping)
{
return mapping->gfp_mask;
}
/* Restricts the given gfp_mask to what the mapping allows. */
static inline gfp_t mapping_gfp_constraint(struct address_space *mapping,
gfp_t gfp_mask)
{
return mapping_gfp_mask(mapping) & gfp_mask;
}
/*
* This is non-atomic. Only to be used before the mapping is activated.
* Probably needs a barrier...
*/
static inline void mapping_set_gfp_mask(struct address_space *m, gfp_t mask)
{
m->gfp_mask = mask;
}
/*
* There are some parts of the kernel which assume that PMD entries
* are exactly HPAGE_PMD_ORDER. Those should be fixed, but until then,
* limit the maximum allocation order to PMD size. I'm not aware of any
* assumptions about maximum order if THP are disabled, but 8 seems like
* a good order (that's 1MB if you're using 4kB pages)
*/
#ifdef CONFIG_TRANSPARENT_HUGEPAGE
#define PREFERRED_MAX_PAGECACHE_ORDER HPAGE_PMD_ORDER
#else
#define PREFERRED_MAX_PAGECACHE_ORDER 8
#endif
/*
* xas_split_alloc() does not support arbitrary orders. This implies no
* 512MB THP on ARM64 with 64KB base page size.
*/
#define MAX_XAS_ORDER (XA_CHUNK_SHIFT * 2 - 1)
#define MAX_PAGECACHE_ORDER min(MAX_XAS_ORDER, PREFERRED_MAX_PAGECACHE_ORDER)
/**
* mapping_set_large_folios() - Indicate the file supports large folios.
* @mapping: The file.
*
* The filesystem should call this function in its inode constructor to
* indicate that the VFS can use large folios to cache the contents of
* the file.
*
* Context: This should not be called while the inode is active as it
* is non-atomic.
*/
static inline void mapping_set_large_folios(struct address_space *mapping)
{
__set_bit(AS_LARGE_FOLIO_SUPPORT, &mapping->flags);
}
/*
* Large folio support currently depends on THP. These dependencies are
* being worked on but are not yet fixed.
*/
static inline bool mapping_large_folio_support(struct address_space *mapping)
{
return IS_ENABLED(CONFIG_TRANSPARENT_HUGEPAGE) &&
test_bit(AS_LARGE_FOLIO_SUPPORT, &mapping->flags);
}
/* Return the maximum folio size for this pagecache mapping, in bytes. */
static inline size_t mapping_max_folio_size(struct address_space *mapping)
{
if (mapping_large_folio_support(mapping))
return PAGE_SIZE << MAX_PAGECACHE_ORDER;
return PAGE_SIZE;
}
static inline int filemap_nr_thps(struct address_space *mapping)
{
#ifdef CONFIG_READ_ONLY_THP_FOR_FS
return atomic_read(&mapping->nr_thps);
#else
return 0;
#endif
}
static inline void filemap_nr_thps_inc(struct address_space *mapping)
{
#ifdef CONFIG_READ_ONLY_THP_FOR_FS
if (!mapping_large_folio_support(mapping))
atomic_inc(&mapping->nr_thps);
#else
WARN_ON_ONCE(mapping_large_folio_support(mapping) == 0);
#endif
}
static inline void filemap_nr_thps_dec(struct address_space *mapping)
{
#ifdef CONFIG_READ_ONLY_THP_FOR_FS
if (!mapping_large_folio_support(mapping))
atomic_dec(&mapping->nr_thps);
#else
WARN_ON_ONCE(mapping_large_folio_support(mapping) == 0);
#endif
}
struct address_space *page_mapping(struct page *);
struct address_space *folio_mapping(struct folio *);
struct address_space *swapcache_mapping(struct folio *);
/**
* folio_file_mapping - Find the mapping this folio belongs to.
* @folio: The folio.
*
* For folios which are in the page cache, return the mapping that this
* page belongs to. Folios in the swap cache return the mapping of the
* swap file or swap device where the data is stored. This is different
* from the mapping returned by folio_mapping(). The only reason to
* use it is if, like NFS, you return 0 from ->activate_swapfile.
*
* Do not call this for folios which aren't in the page cache or swap cache.
*/
static inline struct address_space *folio_file_mapping(struct folio *folio)
{
if (unlikely(folio_test_swapcache(folio)))
return swapcache_mapping(folio);
return folio->mapping;
}
/**
* folio_flush_mapping - Find the file mapping this folio belongs to.
* @folio: The folio.
*
* For folios which are in the page cache, return the mapping that this
* page belongs to. Anonymous folios return NULL, even if they're in
* the swap cache. Other kinds of folio also return NULL.
*
* This is ONLY used by architecture cache flushing code. If you aren't
* writing cache flushing code, you want either folio_mapping() or
* folio_file_mapping().
*/
static inline struct address_space *folio_flush_mapping(struct folio *folio)
{
if (unlikely(folio_test_swapcache(folio)))
return NULL;
return folio_mapping(folio);
}
static inline struct address_space *page_file_mapping(struct page *page)
{
return folio_file_mapping(page_folio(page));
}
/**
* folio_inode - Get the host inode for this folio.
* @folio: The folio.
*
* For folios which are in the page cache, return the inode that this folio
* belongs to.
*
* Do not call this for folios which aren't in the page cache.
*/
static inline struct inode *folio_inode(struct folio *folio)
{
return folio->mapping->host;
}
/**
* folio_attach_private - Attach private data to a folio.
* @folio: Folio to attach data to.
* @data: Data to attach to folio.
*
* Attaching private data to a folio increments the page's reference count.
* The data must be detached before the folio will be freed.
*/
static inline void folio_attach_private(struct folio *folio, void *data)
{
folio_get(folio);
folio->private = data;
folio_set_private(folio);
}
/**
* folio_change_private - Change private data on a folio.
* @folio: Folio to change the data on.
* @data: Data to set on the folio.
*
* Change the private data attached to a folio and return the old
* data. The page must previously have had data attached and the data
* must be detached before the folio will be freed.
*
* Return: Data that was previously attached to the folio.
*/
static inline void *folio_change_private(struct folio *folio, void *data)
{
void *old = folio_get_private(folio);
folio->private = data;
return old;
}
/**
* folio_detach_private - Detach private data from a folio.
* @folio: Folio to detach data from.
*
* Removes the data that was previously attached to the folio and decrements
* the refcount on the page.
*
* Return: Data that was attached to the folio.
*/
static inline void *folio_detach_private(struct folio *folio)
{
void *data = folio_get_private(folio);
if (!folio_test_private(folio))
return NULL;
folio_clear_private(folio);
folio->private = NULL;
folio_put(folio);
return data;
}
static inline void attach_page_private(struct page *page, void *data)
{
folio_attach_private(page_folio(page), data);
}
static inline void *detach_page_private(struct page *page)
{
return folio_detach_private(page_folio(page));
}
#ifdef CONFIG_NUMA
struct folio *filemap_alloc_folio(gfp_t gfp, unsigned int order);
#else
static inline struct folio *filemap_alloc_folio(gfp_t gfp, unsigned int order)
{
return folio_alloc(gfp, order);
}
#endif
static inline struct page *__page_cache_alloc(gfp_t gfp)
{
return &filemap_alloc_folio(gfp, 0)->page;
}
static inline struct page *page_cache_alloc(struct address_space *x)
{
return __page_cache_alloc(mapping_gfp_mask(x));
}
static inline gfp_t readahead_gfp_mask(struct address_space *x)
{
return mapping_gfp_mask(x) | __GFP_NORETRY | __GFP_NOWARN;
}
typedef int filler_t(struct file *, struct folio *);
pgoff_t page_cache_next_miss(struct address_space *mapping,
pgoff_t index, unsigned long max_scan);
pgoff_t page_cache_prev_miss(struct address_space *mapping,
pgoff_t index, unsigned long max_scan);
/**
* typedef fgf_t - Flags for getting folios from the page cache.
*
* Most users of the page cache will not need to use these flags;
* there are convenience functions such as filemap_get_folio() and
* filemap_lock_folio(). For users which need more control over exactly
* what is done with the folios, these flags to __filemap_get_folio()
* are available.
*
* * %FGP_ACCESSED - The folio will be marked accessed.
* * %FGP_LOCK - The folio is returned locked.
* * %FGP_CREAT - If no folio is present then a new folio is allocated,
* added to the page cache and the VM's LRU list. The folio is
* returned locked.
* * %FGP_FOR_MMAP - The caller wants to do its own locking dance if the
* folio is already in cache. If the folio was allocated, unlock it
* before returning so the caller can do the same dance.
* * %FGP_WRITE - The folio will be written to by the caller.
* * %FGP_NOFS - __GFP_FS will get cleared in gfp.
* * %FGP_NOWAIT - Don't block on the folio lock.
* * %FGP_STABLE - Wait for the folio to be stable (finished writeback)
* * %FGP_WRITEBEGIN - The flags to use in a filesystem write_begin()
* implementation.
*/
typedef unsigned int __bitwise fgf_t;
#define FGP_ACCESSED ((__force fgf_t)0x00000001)
#define FGP_LOCK ((__force fgf_t)0x00000002)
#define FGP_CREAT ((__force fgf_t)0x00000004)
#define FGP_WRITE ((__force fgf_t)0x00000008)
#define FGP_NOFS ((__force fgf_t)0x00000010)
#define FGP_NOWAIT ((__force fgf_t)0x00000020)
#define FGP_FOR_MMAP ((__force fgf_t)0x00000040)
#define FGP_STABLE ((__force fgf_t)0x00000080)
#define FGF_GET_ORDER(fgf) (((__force unsigned)fgf) >> 26) /* top 6 bits */
#define FGP_WRITEBEGIN (FGP_LOCK | FGP_WRITE | FGP_CREAT | FGP_STABLE)
/**
* fgf_set_order - Encode a length in the fgf_t flags.
* @size: The suggested size of the folio to create.
*
* The caller of __filemap_get_folio() can use this to suggest a preferred
* size for the folio that is created. If there is already a folio at
* the index, it will be returned, no matter what its size. If a folio
* is freshly created, it may be of a different size than requested
* due to alignment constraints, memory pressure, or the presence of
* other folios at nearby indices.
*/
static inline fgf_t fgf_set_order(size_t size)
{
unsigned int shift = ilog2(size);
if (shift <= PAGE_SHIFT)
return 0;
return (__force fgf_t)((shift - PAGE_SHIFT) << 26);
}
void *filemap_get_entry(struct address_space *mapping, pgoff_t index);
struct folio *__filemap_get_folio(struct address_space *mapping, pgoff_t index,
fgf_t fgp_flags, gfp_t gfp);
struct page *pagecache_get_page(struct address_space *mapping, pgoff_t index,
fgf_t fgp_flags, gfp_t gfp);
/**
* filemap_get_folio - Find and get a folio.
* @mapping: The address_space to search.
* @index: The page index.
*
* Looks up the page cache entry at @mapping & @index. If a folio is
* present, it is returned with an increased refcount.
*
* Return: A folio or ERR_PTR(-ENOENT) if there is no folio in the cache for
* this index. Will not return a shadow, swap or DAX entry.
*/
static inline struct folio *filemap_get_folio(struct address_space *mapping,
pgoff_t index)
{
return __filemap_get_folio(mapping, index, 0, 0);
}
/**
* filemap_lock_folio - Find and lock a folio.
* @mapping: The address_space to search.
* @index: The page index.
*
* Looks up the page cache entry at @mapping & @index. If a folio is
* present, it is returned locked with an increased refcount.
*
* Context: May sleep.
* Return: A folio or ERR_PTR(-ENOENT) if there is no folio in the cache for
* this index. Will not return a shadow, swap or DAX entry.
*/
static inline struct folio *filemap_lock_folio(struct address_space *mapping,
pgoff_t index)
{
return __filemap_get_folio(mapping, index, FGP_LOCK, 0);
}
/**
* filemap_grab_folio - grab a folio from the page cache
* @mapping: The address space to search
* @index: The page index
*
* Looks up the page cache entry at @mapping & @index. If no folio is found,
* a new folio is created. The folio is locked, marked as accessed, and
* returned.
*
* Return: A found or created folio. ERR_PTR(-ENOMEM) if no folio is found
* and failed to create a folio.
*/
static inline struct folio *filemap_grab_folio(struct address_space *mapping,
pgoff_t index)
{
return __filemap_get_folio(mapping, index,
FGP_LOCK | FGP_ACCESSED | FGP_CREAT,
mapping_gfp_mask(mapping));
}
/**
* find_get_page - find and get a page reference
* @mapping: the address_space to search
* @offset: the page index
*
* Looks up the page cache slot at @mapping & @offset. If there is a
* page cache page, it is returned with an increased refcount.
*
* Otherwise, %NULL is returned.
*/
static inline struct page *find_get_page(struct address_space *mapping,
pgoff_t offset)
{
return pagecache_get_page(mapping, offset, 0, 0);
}
static inline struct page *find_get_page_flags(struct address_space *mapping,
pgoff_t offset, fgf_t fgp_flags)
{
return pagecache_get_page(mapping, offset, fgp_flags, 0);
}
/**
* find_lock_page - locate, pin and lock a pagecache page
* @mapping: the address_space to search
* @index: the page index
*
* Looks up the page cache entry at @mapping & @index. If there is a
* page cache page, it is returned locked and with an increased
* refcount.
*
* Context: May sleep.
* Return: A struct page or %NULL if there is no page in the cache for this
* index.
*/
static inline struct page *find_lock_page(struct address_space *mapping,
pgoff_t index)
{
return pagecache_get_page(mapping, index, FGP_LOCK, 0);
}
/**
* find_or_create_page - locate or add a pagecache page
* @mapping: the page's address_space
* @index: the page's index into the mapping
* @gfp_mask: page allocation mode
*
* Looks up the page cache slot at @mapping & @offset. If there is a
* page cache page, it is returned locked and with an increased
* refcount.
*
* If the page is not present, a new page is allocated using @gfp_mask
* and added to the page cache and the VM's LRU list. The page is
* returned locked and with an increased refcount.
*
* On memory exhaustion, %NULL is returned.
*
* find_or_create_page() may sleep, even if @gfp_flags specifies an
* atomic allocation!
*/
static inline struct page *find_or_create_page(struct address_space *mapping,
pgoff_t index, gfp_t gfp_mask)
{
return pagecache_get_page(mapping, index,
FGP_LOCK|FGP_ACCESSED|FGP_CREAT,
gfp_mask);
}
/**
* grab_cache_page_nowait - returns locked page at given index in given cache
* @mapping: target address_space
* @index: the page index
*
* Same as grab_cache_page(), but do not wait if the page is unavailable.
* This is intended for speculative data generators, where the data can
* be regenerated if the page couldn't be grabbed. This routine should
* be safe to call while holding the lock for another page.
*
* Clear __GFP_FS when allocating the page to avoid recursion into the fs
* and deadlock against the caller's locked page.
*/
static inline struct page *grab_cache_page_nowait(struct address_space *mapping,
pgoff_t index)
{
return pagecache_get_page(mapping, index,
FGP_LOCK|FGP_CREAT|FGP_NOFS|FGP_NOWAIT,
mapping_gfp_mask(mapping));
}
#define swapcache_index(folio) __page_file_index(&(folio)->page)
/**
* folio_index - File index of a folio.
* @folio: The folio.
*
* For a folio which is either in the page cache or the swap cache,
* return its index within the address_space it belongs to. If you know
* the page is definitely in the page cache, you can look at the folio's
* index directly.
*
* Return: The index (offset in units of pages) of a folio in its file.
*/
static inline pgoff_t folio_index(struct folio *folio)
{
if (unlikely(folio_test_swapcache(folio)))
return swapcache_index(folio);
return folio->index;
}
/**
* folio_next_index - Get the index of the next folio.
* @folio: The current folio.
*
* Return: The index of the folio which follows this folio in the file.
*/
static inline pgoff_t folio_next_index(struct folio *folio)
{
return folio->index + folio_nr_pages(folio);
}
/**
* folio_file_page - The page for a particular index.
* @folio: The folio which contains this index.
* @index: The index we want to look up.
*
* Sometimes after looking up a folio in the page cache, we need to
* obtain the specific page for an index (eg a page fault).
*
* Return: The page containing the file data for this index.
*/
static inline struct page *folio_file_page(struct folio *folio, pgoff_t index)
{
return folio_page(folio, index & (folio_nr_pages(folio) - 1));
}
/**
* folio_contains - Does this folio contain this index?
* @folio: The folio.
* @index: The page index within the file.
*
* Context: The caller should have the page locked in order to prevent
* (eg) shmem from moving the page between the page cache and swap cache
* and changing its index in the middle of the operation.
* Return: true or false.
*/
static inline bool folio_contains(struct folio *folio, pgoff_t index)
{
return index - folio_index(folio) < folio_nr_pages(folio);
}
/*
* Given the page we found in the page cache, return the page corresponding
* to this index in the file
*/
static inline struct page *find_subpage(struct page *head, pgoff_t index)
{
/* HugeTLBfs wants the head page regardless */
if (PageHuge(head))
return head;
return head + (index & (thp_nr_pages(head) - 1));
}
unsigned filemap_get_folios(struct address_space *mapping, pgoff_t *start,
pgoff_t end, struct folio_batch *fbatch);
unsigned filemap_get_folios_contig(struct address_space *mapping,
pgoff_t *start, pgoff_t end, struct folio_batch *fbatch);
unsigned filemap_get_folios_tag(struct address_space *mapping, pgoff_t *start,
pgoff_t end, xa_mark_t tag, struct folio_batch *fbatch);
struct page *grab_cache_page_write_begin(struct address_space *mapping,
pgoff_t index);
/*
* Returns locked page at given index in given cache, creating it if needed.
*/
static inline struct page *grab_cache_page(struct address_space *mapping,
pgoff_t index)
{
return find_or_create_page(mapping, index, mapping_gfp_mask(mapping));
}
struct folio *read_cache_folio(struct address_space *, pgoff_t index,
filler_t *filler, struct file *file);
struct folio *mapping_read_folio_gfp(struct address_space *, pgoff_t index,
gfp_t flags);
struct page *read_cache_page(struct address_space *, pgoff_t index,
filler_t *filler, struct file *file);
extern struct page * read_cache_page_gfp(struct address_space *mapping,
pgoff_t index, gfp_t gfp_mask);
static inline struct page *read_mapping_page(struct address_space *mapping,
pgoff_t index, struct file *file)
{
return read_cache_page(mapping, index, NULL, file);
}
static inline struct folio *read_mapping_folio(struct address_space *mapping,
pgoff_t index, struct file *file)
{
return read_cache_folio(mapping, index, NULL, file);
}
/*
* Get the offset in PAGE_SIZE (even for hugetlb pages).
*/
static inline pgoff_t page_to_pgoff(struct page *page)
{
struct page *head;
if (likely(!PageTransTail(page)))
return page->index;
head = compound_head(page);
/*
* We don't initialize ->index for tail pages: calculate based on
* head page
*/
return head->index + page - head;
}
/*
* Return byte-offset into filesystem object for page.
*/
static inline loff_t page_offset(struct page *page)
{
return ((loff_t)page->index) << PAGE_SHIFT;
}
static inline loff_t page_file_offset(struct page *page)
{
return ((loff_t)page_index(page)) << PAGE_SHIFT;
}
/**
* folio_pos - Returns the byte position of this folio in its file.
* @folio: The folio.
*/
static inline loff_t folio_pos(struct folio *folio)
{
return page_offset(&folio->page);
}
/**
* folio_file_pos - Returns the byte position of this folio in its file.
* @folio: The folio.
*
* This differs from folio_pos() for folios which belong to a swap file.
* NFS is the only filesystem today which needs to use folio_file_pos().
*/
static inline loff_t folio_file_pos(struct folio *folio)
{
return page_file_offset(&folio->page);
}
/*
* Get the offset in PAGE_SIZE (even for hugetlb folios).
*/
static inline pgoff_t folio_pgoff(struct folio *folio)
{
return folio->index;
}
static inline pgoff_t linear_page_index(struct vm_area_struct *vma,
unsigned long address)
{
pgoff_t pgoff;
pgoff = (address - vma->vm_start) >> PAGE_SHIFT;
pgoff += vma->vm_pgoff;
return pgoff;
}
struct wait_page_key {
struct folio *folio;
int bit_nr;
int page_match;
};
struct wait_page_queue {
struct folio *folio;
int bit_nr;
wait_queue_entry_t wait;
};
static inline bool wake_page_match(struct wait_page_queue *wait_page,
struct wait_page_key *key)
{
if (wait_page->folio != key->folio)
return false;
key->page_match = 1;
if (wait_page->bit_nr != key->bit_nr)
return false;
return true;
}
void __folio_lock(struct folio *folio);
int __folio_lock_killable(struct folio *folio);
vm_fault_t __folio_lock_or_retry(struct folio *folio, struct vm_fault *vmf);
void unlock_page(struct page *page);
void folio_unlock(struct folio *folio);
/**
* folio_trylock() - Attempt to lock a folio.
* @folio: The folio to attempt to lock.
*
* Sometimes it is undesirable to wait for a folio to be unlocked (eg
* when the locks are being taken in the wrong order, or if making
* progress through a batch of folios is more important than processing
* them in order). Usually folio_lock() is the correct function to call.
*
* Context: Any context.
* Return: Whether the lock was successfully acquired.
*/
static inline bool folio_trylock(struct folio *folio)
{
return likely(!test_and_set_bit_lock(PG_locked, folio_flags(folio, 0)));
}
/*
* Return true if the page was successfully locked
*/
static inline int trylock_page(struct page *page)
{
return folio_trylock(page_folio(page));
}
/**
* folio_lock() - Lock this folio.
* @folio: The folio to lock.
*
* The folio lock protects against many things, probably more than it
* should. It is primarily held while a folio is being brought uptodate,
* either from its backing file or from swap. It is also held while a
* folio is being truncated from its address_space, so holding the lock
* is sufficient to keep folio->mapping stable.
*
* The folio lock is also held while write() is modifying the page to
* provide POSIX atomicity guarantees (as long as the write does not
* cross a page boundary). Other modifications to the data in the folio
* do not hold the folio lock and can race with writes, eg DMA and stores
* to mapped pages.
*
* Context: May sleep. If you need to acquire the locks of two or
* more folios, they must be in order of ascending index, if they are
* in the same address_space. If they are in different address_spaces,
* acquire the lock of the folio which belongs to the address_space which
* has the lowest address in memory first.
*/
static inline void folio_lock(struct folio *folio)
{
might_sleep();
if (!folio_trylock(folio))
__folio_lock(folio);
}
/**
* lock_page() - Lock the folio containing this page.
* @page: The page to lock.
*
* See folio_lock() for a description of what the lock protects.
* This is a legacy function and new code should probably use folio_lock()
* instead.
*
* Context: May sleep. Pages in the same folio share a lock, so do not
* attempt to lock two pages which share a folio.
*/
static inline void lock_page(struct page *page)
{
struct folio *folio;
might_sleep();
folio = page_folio(page);
if (!folio_trylock(folio))
__folio_lock(folio);
}
/**
* folio_lock_killable() - Lock this folio, interruptible by a fatal signal.
* @folio: The folio to lock.
*
* Attempts to lock the folio, like folio_lock(), except that the sleep
* to acquire the lock is interruptible by a fatal signal.
*
* Context: May sleep; see folio_lock().
* Return: 0 if the lock was acquired; -EINTR if a fatal signal was received.
*/
static inline int folio_lock_killable(struct folio *folio)
{
might_sleep();
if (!folio_trylock(folio))
return __folio_lock_killable(folio);
return 0;
}
/*
* folio_lock_or_retry - Lock the folio, unless this would block and the
* caller indicated that it can handle a retry.
*
* Return value and mmap_lock implications depend on flags; see
* __folio_lock_or_retry().
*/
static inline vm_fault_t folio_lock_or_retry(struct folio *folio,
struct vm_fault *vmf)
{
might_sleep();
if (!folio_trylock(folio))
return __folio_lock_or_retry(folio, vmf);
return 0;
}
/*
* This is exported only for folio_wait_locked/folio_wait_writeback, etc.,
* and should not be used directly.
*/
void folio_wait_bit(struct folio *folio, int bit_nr);
int folio_wait_bit_killable(struct folio *folio, int bit_nr);
/*
* Wait for a folio to be unlocked.
*
* This must be called with the caller "holding" the folio,
* ie with increased folio reference count so that the folio won't
* go away during the wait.
*/
static inline void folio_wait_locked(struct folio *folio)
{
if (folio_test_locked(folio))
folio_wait_bit(folio, PG_locked);
}
static inline int folio_wait_locked_killable(struct folio *folio)
{
if (!folio_test_locked(folio))
return 0;
return folio_wait_bit_killable(folio, PG_locked);
}
static inline void wait_on_page_locked(struct page *page)
{
folio_wait_locked(page_folio(page));
}
void folio_end_read(struct folio *folio, bool success);
void wait_on_page_writeback(struct page *page);
void folio_wait_writeback(struct folio *folio);
int folio_wait_writeback_killable(struct folio *folio);
void end_page_writeback(struct page *page);
void folio_end_writeback(struct folio *folio);
void wait_for_stable_page(struct page *page);
void folio_wait_stable(struct folio *folio);
void __folio_mark_dirty(struct folio *folio, struct address_space *, int warn);
static inline void __set_page_dirty(struct page *page,
struct address_space *mapping, int warn)
{
__folio_mark_dirty(page_folio(page), mapping, warn);
}
void folio_account_cleaned(struct folio *folio, struct bdi_writeback *wb);
void __folio_cancel_dirty(struct folio *folio);
static inline void folio_cancel_dirty(struct folio *folio)
{
/* Avoid atomic ops, locking, etc. when not actually needed. */
if (folio_test_dirty(folio))
__folio_cancel_dirty(folio);
}
bool folio_clear_dirty_for_io(struct folio *folio);
bool clear_page_dirty_for_io(struct page *page);
void folio_invalidate(struct folio *folio, size_t offset, size_t length);
int __set_page_dirty_nobuffers(struct page *page);
bool noop_dirty_folio(struct address_space *mapping, struct folio *folio);
#ifdef CONFIG_MIGRATION
int filemap_migrate_folio(struct address_space *mapping, struct folio *dst,
struct folio *src, enum migrate_mode mode);
#else
#define filemap_migrate_folio NULL
#endif
void folio_end_private_2(struct folio *folio);
void folio_wait_private_2(struct folio *folio);
int folio_wait_private_2_killable(struct folio *folio);
/*
* Add an arbitrary waiter to a page's wait queue
*/
void folio_add_wait_queue(struct folio *folio, wait_queue_entry_t *waiter);
/*
* Fault in userspace address range.
*/
size_t fault_in_writeable(char __user *uaddr, size_t size);
size_t fault_in_subpage_writeable(char __user *uaddr, size_t size);
size_t fault_in_safe_writeable(const char __user *uaddr, size_t size);
size_t fault_in_readable(const char __user *uaddr, size_t size);
int add_to_page_cache_lru(struct page *page, struct address_space *mapping,
pgoff_t index, gfp_t gfp);
int filemap_add_folio(struct address_space *mapping, struct folio *folio,
pgoff_t index, gfp_t gfp);
void filemap_remove_folio(struct folio *folio);
void __filemap_remove_folio(struct folio *folio, void *shadow);
void replace_page_cache_folio(struct folio *old, struct folio *new);
void delete_from_page_cache_batch(struct address_space *mapping,
struct folio_batch *fbatch);
bool filemap_release_folio(struct folio *folio, gfp_t gfp);
loff_t mapping_seek_hole_data(struct address_space *, loff_t start, loff_t end,
int whence);
/* Must be non-static for BPF error injection */
int __filemap_add_folio(struct address_space *mapping, struct folio *folio,
pgoff_t index, gfp_t gfp, void **shadowp);
bool filemap_range_has_writeback(struct address_space *mapping,
loff_t start_byte, loff_t end_byte);
/**
* filemap_range_needs_writeback - check if range potentially needs writeback
* @mapping: address space within which to check
* @start_byte: offset in bytes where the range starts
* @end_byte: offset in bytes where the range ends (inclusive)
*
* Find at least one page in the range supplied, usually used to check if
* direct writing in this range will trigger a writeback. Used by O_DIRECT
* read/write with IOCB_NOWAIT, to see if the caller needs to do
* filemap_write_and_wait_range() before proceeding.
*
* Return: %true if the caller should do filemap_write_and_wait_range() before
* doing O_DIRECT to a page in this range, %false otherwise.
*/
static inline bool filemap_range_needs_writeback(struct address_space *mapping,
loff_t start_byte,
loff_t end_byte)
{
if (!mapping->nrpages)
return false;
if (!mapping_tagged(mapping, PAGECACHE_TAG_DIRTY) &&
!mapping_tagged(mapping, PAGECACHE_TAG_WRITEBACK))
return false;
return filemap_range_has_writeback(mapping, start_byte, end_byte);
}
/**
* struct readahead_control - Describes a readahead request.
*
* A readahead request is for consecutive pages. Filesystems which
* implement the ->readahead method should call readahead_page() or
* readahead_page_batch() in a loop and attempt to start I/O against
* each page in the request.
*
* Most of the fields in this struct are private and should be accessed
* by the functions below.
*
* @file: The file, used primarily by network filesystems for authentication.
* May be NULL if invoked internally by the filesystem.
* @mapping: Readahead this filesystem object.
* @ra: File readahead state. May be NULL.
*/
struct readahead_control {
struct file *file;
struct address_space *mapping;
struct file_ra_state *ra;
/* private: use the readahead_* accessors instead */
pgoff_t _index;
unsigned int _nr_pages;
unsigned int _batch_count;
bool _workingset;
unsigned long _pflags;
};
#define DEFINE_READAHEAD(ractl, f, r, m, i) \
struct readahead_control ractl = { \
.file = f, \
.mapping = m, \
.ra = r, \
._index = i, \
}
#define VM_READAHEAD_PAGES (SZ_128K / PAGE_SIZE)
void page_cache_ra_unbounded(struct readahead_control *,
unsigned long nr_to_read, unsigned long lookahead_count);
void page_cache_sync_ra(struct readahead_control *, unsigned long req_count);
void page_cache_async_ra(struct readahead_control *, struct folio *,
unsigned long req_count);
void readahead_expand(struct readahead_control *ractl,
loff_t new_start, size_t new_len);
/**
* page_cache_sync_readahead - generic file readahead
* @mapping: address_space which holds the pagecache and I/O vectors
* @ra: file_ra_state which holds the readahead state
* @file: Used by the filesystem for authentication.
* @index: Index of first page to be read.
* @req_count: Total number of pages being read by the caller.
*
* page_cache_sync_readahead() should be called when a cache miss happened:
* it will submit the read. The readahead logic may decide to piggyback more
* pages onto the read request if access patterns suggest it will improve
* performance.
*/
static inline
void page_cache_sync_readahead(struct address_space *mapping,
struct file_ra_state *ra, struct file *file, pgoff_t index,
unsigned long req_count)
{
DEFINE_READAHEAD(ractl, file, ra, mapping, index);
page_cache_sync_ra(&ractl, req_count);
}
/**
* page_cache_async_readahead - file readahead for marked pages
* @mapping: address_space which holds the pagecache and I/O vectors
* @ra: file_ra_state which holds the readahead state
* @file: Used by the filesystem for authentication.
* @folio: The folio at @index which triggered the readahead call.
* @index: Index of first page to be read.
* @req_count: Total number of pages being read by the caller.
*
* page_cache_async_readahead() should be called when a page is used which
* is marked as PageReadahead; this is a marker to suggest that the application
* has used up enough of the readahead window that we should start pulling in
* more pages.
*/
static inline
void page_cache_async_readahead(struct address_space *mapping,
struct file_ra_state *ra, struct file *file,
struct folio *folio, pgoff_t index, unsigned long req_count)
{
DEFINE_READAHEAD(ractl, file, ra, mapping, index);
page_cache_async_ra(&ractl, folio, req_count);
}
static inline struct folio *__readahead_folio(struct readahead_control *ractl)
{
struct folio *folio;
BUG_ON(ractl->_batch_count > ractl->_nr_pages);
ractl->_nr_pages -= ractl->_batch_count;
ractl->_index += ractl->_batch_count;
if (!ractl->_nr_pages) {
ractl->_batch_count = 0;
return NULL;
}
folio = xa_load(&ractl->mapping->i_pages, ractl->_index);
VM_BUG_ON_FOLIO(!folio_test_locked(folio), folio);
ractl->_batch_count = folio_nr_pages(folio);
return folio;
}
/**
* readahead_page - Get the next page to read.
* @ractl: The current readahead request.
*
* Context: The page is locked and has an elevated refcount. The caller
* should decreases the refcount once the page has been submitted for I/O
* and unlock the page once all I/O to that page has completed.
* Return: A pointer to the next page, or %NULL if we are done.
*/
static inline struct page *readahead_page(struct readahead_control *ractl)
{
struct folio *folio = __readahead_folio(ractl);
return &folio->page;
}
/**
* readahead_folio - Get the next folio to read.
* @ractl: The current readahead request.
*
* Context: The folio is locked. The caller should unlock the folio once
* all I/O to that folio has completed.
* Return: A pointer to the next folio, or %NULL if we are done.
*/
static inline struct folio *readahead_folio(struct readahead_control *ractl)
{
struct folio *folio = __readahead_folio(ractl);
if (folio)
folio_put(folio);
return folio;
}
static inline unsigned int __readahead_batch(struct readahead_control *rac,
struct page **array, unsigned int array_sz)
{
unsigned int i = 0;
XA_STATE(xas, &rac->mapping->i_pages, 0);
struct page *page;
BUG_ON(rac->_batch_count > rac->_nr_pages);
rac->_nr_pages -= rac->_batch_count;
rac->_index += rac->_batch_count;
rac->_batch_count = 0;
xas_set(&xas, rac->_index);
rcu_read_lock();
xas_for_each(&xas, page, rac->_index + rac->_nr_pages - 1) {
if (xas_retry(&xas, page))
continue;
VM_BUG_ON_PAGE(!PageLocked(page), page);
VM_BUG_ON_PAGE(PageTail(page), page);
array[i++] = page;
rac->_batch_count += thp_nr_pages(page);
if (i == array_sz)
break;
}
rcu_read_unlock();
return i;
}
/**
* readahead_page_batch - Get a batch of pages to read.
* @rac: The current readahead request.
* @array: An array of pointers to struct page.
*
* Context: The pages are locked and have an elevated refcount. The caller
* should decreases the refcount once the page has been submitted for I/O
* and unlock the page once all I/O to that page has completed.
* Return: The number of pages placed in the array. 0 indicates the request
* is complete.
*/
#define readahead_page_batch(rac, array) \
__readahead_batch(rac, array, ARRAY_SIZE(array))
/**
* readahead_pos - The byte offset into the file of this readahead request.
* @rac: The readahead request.
*/
static inline loff_t readahead_pos(struct readahead_control *rac)
{
return (loff_t)rac->_index * PAGE_SIZE;
}
/**
* readahead_length - The number of bytes in this readahead request.
* @rac: The readahead request.
*/
static inline size_t readahead_length(struct readahead_control *rac)
{
return rac->_nr_pages * PAGE_SIZE;
}
/**
* readahead_index - The index of the first page in this readahead request.
* @rac: The readahead request.
*/
static inline pgoff_t readahead_index(struct readahead_control *rac)
{
return rac->_index;
}
/**
* readahead_count - The number of pages in this readahead request.
* @rac: The readahead request.
*/
static inline unsigned int readahead_count(struct readahead_control *rac)
{
return rac->_nr_pages;
}
/**
* readahead_batch_length - The number of bytes in the current batch.
* @rac: The readahead request.
*/
static inline size_t readahead_batch_length(struct readahead_control *rac)
{
return rac->_batch_count * PAGE_SIZE;
}
static inline unsigned long dir_pages(struct inode *inode)
{
return (unsigned long)(inode->i_size + PAGE_SIZE - 1) >>
PAGE_SHIFT;
}
/**
* folio_mkwrite_check_truncate - check if folio was truncated
* @folio: the folio to check
* @inode: the inode to check the folio against
*
* Return: the number of bytes in the folio up to EOF,
* or -EFAULT if the folio was truncated.
*/
static inline ssize_t folio_mkwrite_check_truncate(struct folio *folio,
struct inode *inode)
{
loff_t size = i_size_read(inode);
pgoff_t index = size >> PAGE_SHIFT;
size_t offset = offset_in_folio(folio, size);
if (!folio->mapping)
return -EFAULT;
/* folio is wholly inside EOF */
if (folio_next_index(folio) - 1 < index)
return folio_size(folio);
/* folio is wholly past EOF */
if (folio->index > index || !offset)
return -EFAULT;
/* folio is partially inside EOF */
return offset;
}
/**
* page_mkwrite_check_truncate - check if page was truncated
* @page: the page to check
* @inode: the inode to check the page against
*
* Returns the number of bytes in the page up to EOF,
* or -EFAULT if the page was truncated.
*/
static inline int page_mkwrite_check_truncate(struct page *page,
struct inode *inode)
{
loff_t size = i_size_read(inode);
pgoff_t index = size >> PAGE_SHIFT;
int offset = offset_in_page(size);
if (page->mapping != inode->i_mapping)
return -EFAULT;
/* page is wholly inside EOF */
if (page->index < index)
return PAGE_SIZE;
/* page is wholly past EOF */
if (page->index > index || !offset)
return -EFAULT;
/* page is partially inside EOF */
return offset;
}
/**
* i_blocks_per_folio - How many blocks fit in this folio.
* @inode: The inode which contains the blocks.
* @folio: The folio.
*
* If the block size is larger than the size of this folio, return zero.
*
* Context: The caller should hold a refcount on the folio to prevent it
* from being split.
* Return: The number of filesystem blocks covered by this folio.
*/
static inline
unsigned int i_blocks_per_folio(struct inode *inode, struct folio *folio)
{
return folio_size(folio) >> inode->i_blkbits;
}
static inline
unsigned int i_blocks_per_page(struct inode *inode, struct page *page)
{
return i_blocks_per_folio(inode, page_folio(page));
}
#endif /* _LINUX_PAGEMAP_H */
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