mirror of
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
synced 2024-09-04 01:49:36 +00:00
![Minchan Kim](/assets/img/avatar_default.png)
The swap address_space doesn't have host. Thus, it makes kernel crash once
swap write meets error. Fix it.
Fixes: 735e4ae5ba
("vfs: track per-sb writeback errors and report them to syncfs")
Signed-off-by: Minchan Kim <minchan@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Jeff Layton <jlayton@kernel.org>
Cc: Jan Kara <jack@suse.cz>
Cc: Andres Freund <andres@anarazel.de>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Dave Chinner <david@fromorbit.com>
Cc: David Howells <dhowells@redhat.com>
Cc: <stable@vger.kernel.org>
Link: https://lkml.kernel.org/r/20201010000650.750063-1-minchan@kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
903 lines
26 KiB
C
903 lines
26 KiB
C
/* 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 pagevec;
|
|
|
|
/*
|
|
* 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,
|
|
};
|
|
|
|
/**
|
|
* 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 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;
|
|
}
|
|
|
|
void release_pages(struct page **pages, int nr);
|
|
|
|
/*
|
|
* speculatively take a reference to a page.
|
|
* If the page is free (_refcount == 0), then _refcount is untouched, and 0
|
|
* is returned. Otherwise, _refcount is incremented by 1 and 1 is returned.
|
|
*
|
|
* This function must be called inside the same rcu_read_lock() section as has
|
|
* been used to lookup the page in the pagecache radix-tree (or page table):
|
|
* this allows allocators to use a synchronize_rcu() to stabilize _refcount.
|
|
*
|
|
* Unless an RCU grace period has passed, the count of all pages coming out
|
|
* of the allocator must be considered unstable. page_count may return higher
|
|
* than expected, and put_page must be able to do the right thing when the
|
|
* page has been finished with, no matter what it is subsequently allocated
|
|
* for (because put_page is what is used here to drop an invalid speculative
|
|
* reference).
|
|
*
|
|
* This is the interesting part of the lockless pagecache (and lockless
|
|
* get_user_pages) locking protocol, where the lookup-side (eg. find_get_page)
|
|
* has the following pattern:
|
|
* 1. find page in radix tree
|
|
* 2. conditionally increment refcount
|
|
* 3. check the page is still in pagecache (if no, goto 1)
|
|
*
|
|
* Remove-side that cares about stability of _refcount (eg. reclaim) has the
|
|
* following (with the i_pages lock held):
|
|
* A. atomically check refcount is correct and set it to 0 (atomic_cmpxchg)
|
|
* B. remove page from pagecache
|
|
* C. free the page
|
|
*
|
|
* There are 2 critical interleavings that matter:
|
|
* - 2 runs before A: in this case, A sees elevated refcount and bails out
|
|
* - A runs before 2: in this case, 2 sees zero refcount and retries;
|
|
* subsequently, B will complete and 1 will find no page, causing the
|
|
* lookup to return NULL.
|
|
*
|
|
* It is possible that between 1 and 2, the page is removed then the exact same
|
|
* page is inserted into the same position in pagecache. That's OK: the
|
|
* old find_get_page using a lock could equally have run before or after
|
|
* such a re-insertion, depending on order that locks are granted.
|
|
*
|
|
* Lookups racing against pagecache insertion isn't a big problem: either 1
|
|
* will find the page or it will not. Likewise, the old find_get_page could run
|
|
* either before the insertion or afterwards, depending on timing.
|
|
*/
|
|
static inline int __page_cache_add_speculative(struct page *page, int count)
|
|
{
|
|
#ifdef CONFIG_TINY_RCU
|
|
# ifdef CONFIG_PREEMPT_COUNT
|
|
VM_BUG_ON(!in_atomic() && !irqs_disabled());
|
|
# endif
|
|
/*
|
|
* Preempt must be disabled here - we rely on rcu_read_lock doing
|
|
* this for us.
|
|
*
|
|
* Pagecache won't be truncated from interrupt context, so if we have
|
|
* found a page in the radix tree here, we have pinned its refcount by
|
|
* disabling preempt, and hence no need for the "speculative get" that
|
|
* SMP requires.
|
|
*/
|
|
VM_BUG_ON_PAGE(page_count(page) == 0, page);
|
|
page_ref_add(page, count);
|
|
|
|
#else
|
|
if (unlikely(!page_ref_add_unless(page, count, 0))) {
|
|
/*
|
|
* Either the page has been freed, or will be freed.
|
|
* In either case, retry here and the caller should
|
|
* do the right thing (see comments above).
|
|
*/
|
|
return 0;
|
|
}
|
|
#endif
|
|
VM_BUG_ON_PAGE(PageTail(page), page);
|
|
|
|
return 1;
|
|
}
|
|
|
|
static inline int page_cache_get_speculative(struct page *page)
|
|
{
|
|
return __page_cache_add_speculative(page, 1);
|
|
}
|
|
|
|
static inline int page_cache_add_speculative(struct page *page, int count)
|
|
{
|
|
return __page_cache_add_speculative(page, count);
|
|
}
|
|
|
|
/**
|
|
* attach_page_private - Attach private data to a page.
|
|
* @page: Page to attach data to.
|
|
* @data: Data to attach to page.
|
|
*
|
|
* Attaching private data to a page increments the page's reference count.
|
|
* The data must be detached before the page will be freed.
|
|
*/
|
|
static inline void attach_page_private(struct page *page, void *data)
|
|
{
|
|
get_page(page);
|
|
set_page_private(page, (unsigned long)data);
|
|
SetPagePrivate(page);
|
|
}
|
|
|
|
/**
|
|
* detach_page_private - Detach private data from a page.
|
|
* @page: Page to detach data from.
|
|
*
|
|
* Removes the data that was previously attached to the page and decrements
|
|
* the refcount on the page.
|
|
*
|
|
* Return: Data that was attached to the page.
|
|
*/
|
|
static inline void *detach_page_private(struct page *page)
|
|
{
|
|
void *data = (void *)page_private(page);
|
|
|
|
if (!PagePrivate(page))
|
|
return NULL;
|
|
ClearPagePrivate(page);
|
|
set_page_private(page, 0);
|
|
put_page(page);
|
|
|
|
return data;
|
|
}
|
|
|
|
#ifdef CONFIG_NUMA
|
|
extern struct page *__page_cache_alloc(gfp_t gfp);
|
|
#else
|
|
static inline struct page *__page_cache_alloc(gfp_t gfp)
|
|
{
|
|
return alloc_pages(gfp, 0);
|
|
}
|
|
#endif
|
|
|
|
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(void *, struct page *);
|
|
|
|
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);
|
|
|
|
#define FGP_ACCESSED 0x00000001
|
|
#define FGP_LOCK 0x00000002
|
|
#define FGP_CREAT 0x00000004
|
|
#define FGP_WRITE 0x00000008
|
|
#define FGP_NOFS 0x00000010
|
|
#define FGP_NOWAIT 0x00000020
|
|
#define FGP_FOR_MMAP 0x00000040
|
|
|
|
struct page *pagecache_get_page(struct address_space *mapping, pgoff_t offset,
|
|
int fgp_flags, gfp_t cache_gfp_mask);
|
|
|
|
/**
|
|
* 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, int 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
|
|
* @offset: the page index
|
|
*
|
|
* 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.
|
|
*
|
|
* Otherwise, %NULL is returned.
|
|
*
|
|
* find_lock_page() may sleep.
|
|
*/
|
|
static inline struct page *find_lock_page(struct address_space *mapping,
|
|
pgoff_t offset)
|
|
{
|
|
return pagecache_get_page(mapping, offset, 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));
|
|
}
|
|
|
|
/*
|
|
* 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));
|
|
}
|
|
|
|
struct page *find_get_entry(struct address_space *mapping, pgoff_t offset);
|
|
struct page *find_lock_entry(struct address_space *mapping, pgoff_t offset);
|
|
unsigned find_get_entries(struct address_space *mapping, pgoff_t start,
|
|
unsigned int nr_entries, struct page **entries,
|
|
pgoff_t *indices);
|
|
unsigned find_get_pages_range(struct address_space *mapping, pgoff_t *start,
|
|
pgoff_t end, unsigned int nr_pages,
|
|
struct page **pages);
|
|
static inline unsigned find_get_pages(struct address_space *mapping,
|
|
pgoff_t *start, unsigned int nr_pages,
|
|
struct page **pages)
|
|
{
|
|
return find_get_pages_range(mapping, start, (pgoff_t)-1, nr_pages,
|
|
pages);
|
|
}
|
|
unsigned find_get_pages_contig(struct address_space *mapping, pgoff_t start,
|
|
unsigned int nr_pages, struct page **pages);
|
|
unsigned find_get_pages_range_tag(struct address_space *mapping, pgoff_t *index,
|
|
pgoff_t end, xa_mark_t tag, unsigned int nr_pages,
|
|
struct page **pages);
|
|
static inline unsigned find_get_pages_tag(struct address_space *mapping,
|
|
pgoff_t *index, xa_mark_t tag, unsigned int nr_pages,
|
|
struct page **pages)
|
|
{
|
|
return find_get_pages_range_tag(mapping, index, (pgoff_t)-1, tag,
|
|
nr_pages, pages);
|
|
}
|
|
|
|
struct page *grab_cache_page_write_begin(struct address_space *mapping,
|
|
pgoff_t index, unsigned flags);
|
|
|
|
/*
|
|
* 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));
|
|
}
|
|
|
|
extern struct page * read_cache_page(struct address_space *mapping,
|
|
pgoff_t index, filler_t *filler, void *data);
|
|
extern struct page * read_cache_page_gfp(struct address_space *mapping,
|
|
pgoff_t index, gfp_t gfp_mask);
|
|
extern int read_cache_pages(struct address_space *mapping,
|
|
struct list_head *pages, filler_t *filler, void *data);
|
|
|
|
static inline struct page *read_mapping_page(struct address_space *mapping,
|
|
pgoff_t index, void *data)
|
|
{
|
|
return read_cache_page(mapping, index, NULL, data);
|
|
}
|
|
|
|
/*
|
|
* Get index of the page with in radix-tree
|
|
* (TODO: remove once hugetlb pages will have ->index in PAGE_SIZE)
|
|
*/
|
|
static inline pgoff_t page_to_index(struct page *page)
|
|
{
|
|
pgoff_t pgoff;
|
|
|
|
if (likely(!PageTransTail(page)))
|
|
return page->index;
|
|
|
|
/*
|
|
* We don't initialize ->index for tail pages: calculate based on
|
|
* head page
|
|
*/
|
|
pgoff = compound_head(page)->index;
|
|
pgoff += page - compound_head(page);
|
|
return pgoff;
|
|
}
|
|
|
|
/*
|
|
* Get the offset in PAGE_SIZE.
|
|
* (TODO: hugepage should have ->index in PAGE_SIZE)
|
|
*/
|
|
static inline pgoff_t page_to_pgoff(struct page *page)
|
|
{
|
|
if (unlikely(PageHeadHuge(page)))
|
|
return page->index << compound_order(page);
|
|
|
|
return page_to_index(page);
|
|
}
|
|
|
|
/*
|
|
* 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;
|
|
}
|
|
|
|
extern pgoff_t linear_hugepage_index(struct vm_area_struct *vma,
|
|
unsigned long address);
|
|
|
|
static inline pgoff_t linear_page_index(struct vm_area_struct *vma,
|
|
unsigned long address)
|
|
{
|
|
pgoff_t pgoff;
|
|
if (unlikely(is_vm_hugetlb_page(vma)))
|
|
return linear_hugepage_index(vma, address);
|
|
pgoff = (address - vma->vm_start) >> PAGE_SHIFT;
|
|
pgoff += vma->vm_pgoff;
|
|
return pgoff;
|
|
}
|
|
|
|
/* This has the same layout as wait_bit_key - see fs/cachefiles/rdwr.c */
|
|
struct wait_page_key {
|
|
struct page *page;
|
|
int bit_nr;
|
|
int page_match;
|
|
};
|
|
|
|
struct wait_page_queue {
|
|
struct page *page;
|
|
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->page != key->page)
|
|
return false;
|
|
key->page_match = 1;
|
|
|
|
if (wait_page->bit_nr != key->bit_nr)
|
|
return false;
|
|
|
|
return true;
|
|
}
|
|
|
|
extern void __lock_page(struct page *page);
|
|
extern int __lock_page_killable(struct page *page);
|
|
extern int __lock_page_async(struct page *page, struct wait_page_queue *wait);
|
|
extern int __lock_page_or_retry(struct page *page, struct mm_struct *mm,
|
|
unsigned int flags);
|
|
extern void unlock_page(struct page *page);
|
|
|
|
/*
|
|
* Return true if the page was successfully locked
|
|
*/
|
|
static inline int trylock_page(struct page *page)
|
|
{
|
|
page = compound_head(page);
|
|
return (likely(!test_and_set_bit_lock(PG_locked, &page->flags)));
|
|
}
|
|
|
|
/*
|
|
* lock_page may only be called if we have the page's inode pinned.
|
|
*/
|
|
static inline void lock_page(struct page *page)
|
|
{
|
|
might_sleep();
|
|
if (!trylock_page(page))
|
|
__lock_page(page);
|
|
}
|
|
|
|
/*
|
|
* lock_page_killable is like lock_page but can be interrupted by fatal
|
|
* signals. It returns 0 if it locked the page and -EINTR if it was
|
|
* killed while waiting.
|
|
*/
|
|
static inline int lock_page_killable(struct page *page)
|
|
{
|
|
might_sleep();
|
|
if (!trylock_page(page))
|
|
return __lock_page_killable(page);
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* lock_page_async - Lock the page, unless this would block. If the page
|
|
* is already locked, then queue a callback when the page becomes unlocked.
|
|
* This callback can then retry the operation.
|
|
*
|
|
* Returns 0 if the page is locked successfully, or -EIOCBQUEUED if the page
|
|
* was already locked and the callback defined in 'wait' was queued.
|
|
*/
|
|
static inline int lock_page_async(struct page *page,
|
|
struct wait_page_queue *wait)
|
|
{
|
|
if (!trylock_page(page))
|
|
return __lock_page_async(page, wait);
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* lock_page_or_retry - Lock the page, unless this would block and the
|
|
* caller indicated that it can handle a retry.
|
|
*
|
|
* Return value and mmap_lock implications depend on flags; see
|
|
* __lock_page_or_retry().
|
|
*/
|
|
static inline int lock_page_or_retry(struct page *page, struct mm_struct *mm,
|
|
unsigned int flags)
|
|
{
|
|
might_sleep();
|
|
return trylock_page(page) || __lock_page_or_retry(page, mm, flags);
|
|
}
|
|
|
|
/*
|
|
* This is exported only for wait_on_page_locked/wait_on_page_writeback, etc.,
|
|
* and should not be used directly.
|
|
*/
|
|
extern void wait_on_page_bit(struct page *page, int bit_nr);
|
|
extern int wait_on_page_bit_killable(struct page *page, int bit_nr);
|
|
|
|
/*
|
|
* Wait for a page to be unlocked.
|
|
*
|
|
* This must be called with the caller "holding" the page,
|
|
* ie with increased "page->count" so that the page won't
|
|
* go away during the wait..
|
|
*/
|
|
static inline void wait_on_page_locked(struct page *page)
|
|
{
|
|
if (PageLocked(page))
|
|
wait_on_page_bit(compound_head(page), PG_locked);
|
|
}
|
|
|
|
static inline int wait_on_page_locked_killable(struct page *page)
|
|
{
|
|
if (!PageLocked(page))
|
|
return 0;
|
|
return wait_on_page_bit_killable(compound_head(page), PG_locked);
|
|
}
|
|
|
|
extern void put_and_wait_on_page_locked(struct page *page);
|
|
|
|
void wait_on_page_writeback(struct page *page);
|
|
extern void end_page_writeback(struct page *page);
|
|
void wait_for_stable_page(struct page *page);
|
|
|
|
void page_endio(struct page *page, bool is_write, int err);
|
|
|
|
/*
|
|
* Add an arbitrary waiter to a page's wait queue
|
|
*/
|
|
extern void add_page_wait_queue(struct page *page, wait_queue_entry_t *waiter);
|
|
|
|
/*
|
|
* Fault everything in given userspace address range in.
|
|
*/
|
|
static inline int fault_in_pages_writeable(char __user *uaddr, int size)
|
|
{
|
|
char __user *end = uaddr + size - 1;
|
|
|
|
if (unlikely(size == 0))
|
|
return 0;
|
|
|
|
if (unlikely(uaddr > end))
|
|
return -EFAULT;
|
|
/*
|
|
* Writing zeroes into userspace here is OK, because we know that if
|
|
* the zero gets there, we'll be overwriting it.
|
|
*/
|
|
do {
|
|
if (unlikely(__put_user(0, uaddr) != 0))
|
|
return -EFAULT;
|
|
uaddr += PAGE_SIZE;
|
|
} while (uaddr <= end);
|
|
|
|
/* Check whether the range spilled into the next page. */
|
|
if (((unsigned long)uaddr & PAGE_MASK) ==
|
|
((unsigned long)end & PAGE_MASK))
|
|
return __put_user(0, end);
|
|
|
|
return 0;
|
|
}
|
|
|
|
static inline int fault_in_pages_readable(const char __user *uaddr, int size)
|
|
{
|
|
volatile char c;
|
|
const char __user *end = uaddr + size - 1;
|
|
|
|
if (unlikely(size == 0))
|
|
return 0;
|
|
|
|
if (unlikely(uaddr > end))
|
|
return -EFAULT;
|
|
|
|
do {
|
|
if (unlikely(__get_user(c, uaddr) != 0))
|
|
return -EFAULT;
|
|
uaddr += PAGE_SIZE;
|
|
} while (uaddr <= end);
|
|
|
|
/* Check whether the range spilled into the next page. */
|
|
if (((unsigned long)uaddr & PAGE_MASK) ==
|
|
((unsigned long)end & PAGE_MASK)) {
|
|
return __get_user(c, end);
|
|
}
|
|
|
|
(void)c;
|
|
return 0;
|
|
}
|
|
|
|
int add_to_page_cache_locked(struct page *page, struct address_space *mapping,
|
|
pgoff_t index, gfp_t gfp_mask);
|
|
int add_to_page_cache_lru(struct page *page, struct address_space *mapping,
|
|
pgoff_t index, gfp_t gfp_mask);
|
|
extern void delete_from_page_cache(struct page *page);
|
|
extern void __delete_from_page_cache(struct page *page, void *shadow);
|
|
int replace_page_cache_page(struct page *old, struct page *new, gfp_t gfp_mask);
|
|
void delete_from_page_cache_batch(struct address_space *mapping,
|
|
struct pagevec *pvec);
|
|
|
|
#define VM_READAHEAD_PAGES (SZ_128K / PAGE_SIZE)
|
|
|
|
void page_cache_sync_readahead(struct address_space *, struct file_ra_state *,
|
|
struct file *, pgoff_t index, unsigned long req_count);
|
|
void page_cache_async_readahead(struct address_space *, struct file_ra_state *,
|
|
struct file *, struct page *, pgoff_t index,
|
|
unsigned long req_count);
|
|
void page_cache_readahead_unbounded(struct address_space *, struct file *,
|
|
pgoff_t index, unsigned long nr_to_read,
|
|
unsigned long lookahead_count);
|
|
|
|
/*
|
|
* Like add_to_page_cache_locked, but used to add newly allocated pages:
|
|
* the page is new, so we can just run __SetPageLocked() against it.
|
|
*/
|
|
static inline int add_to_page_cache(struct page *page,
|
|
struct address_space *mapping, pgoff_t offset, gfp_t gfp_mask)
|
|
{
|
|
int error;
|
|
|
|
__SetPageLocked(page);
|
|
error = add_to_page_cache_locked(page, mapping, offset, gfp_mask);
|
|
if (unlikely(error))
|
|
__ClearPageLocked(page);
|
|
return error;
|
|
}
|
|
|
|
/**
|
|
* 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.
|
|
*/
|
|
struct readahead_control {
|
|
struct file *file;
|
|
struct address_space *mapping;
|
|
/* private: use the readahead_* accessors instead */
|
|
pgoff_t _index;
|
|
unsigned int _nr_pages;
|
|
unsigned int _batch_count;
|
|
};
|
|
|
|
/**
|
|
* readahead_page - Get the next page to read.
|
|
* @rac: 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 *rac)
|
|
{
|
|
struct page *page;
|
|
|
|
BUG_ON(rac->_batch_count > rac->_nr_pages);
|
|
rac->_nr_pages -= rac->_batch_count;
|
|
rac->_index += rac->_batch_count;
|
|
|
|
if (!rac->_nr_pages) {
|
|
rac->_batch_count = 0;
|
|
return NULL;
|
|
}
|
|
|
|
page = xa_load(&rac->mapping->i_pages, rac->_index);
|
|
VM_BUG_ON_PAGE(!PageLocked(page), page);
|
|
rac->_batch_count = thp_nr_pages(page);
|
|
|
|
return page;
|
|
}
|
|
|
|
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) {
|
|
VM_BUG_ON_PAGE(!PageLocked(page), page);
|
|
VM_BUG_ON_PAGE(PageTail(page), page);
|
|
array[i++] = page;
|
|
rac->_batch_count += thp_nr_pages(page);
|
|
|
|
/*
|
|
* The page cache isn't using multi-index entries yet,
|
|
* so the xas cursor needs to be manually moved to the
|
|
* next index. This can be removed once the page cache
|
|
* is converted.
|
|
*/
|
|
if (PageHead(page))
|
|
xas_set(&xas, rac->_index + rac->_batch_count);
|
|
|
|
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 loff_t readahead_length(struct readahead_control *rac)
|
|
{
|
|
return (loff_t)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;
|
|
}
|
|
|
|
static inline unsigned long dir_pages(struct inode *inode)
|
|
{
|
|
return (unsigned long)(inode->i_size + PAGE_SIZE - 1) >>
|
|
PAGE_SHIFT;
|
|
}
|
|
|
|
/**
|
|
* 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;
|
|
}
|
|
|
|
#endif /* _LINUX_PAGEMAP_H */
|