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git.proxmox.com Git - mirror_ubuntu-eoan-kernel.git/blob - mm/fadvise.c
4 * Copyright (C) 2002, Linus Torvalds
6 * 11Jan2003 akpm@digeo.com
10 #include <linux/kernel.h>
11 #include <linux/file.h>
14 #include <linux/pagemap.h>
15 #include <linux/backing-dev.h>
16 #include <linux/pagevec.h>
17 #include <linux/fadvise.h>
18 #include <linux/writeback.h>
19 #include <linux/syscalls.h>
21 #include <asm/unistd.h>
24 * POSIX_FADV_WILLNEED could set PG_Referenced, and POSIX_FADV_NOREUSE could
25 * deactivate the pages and clear PG_Referenced.
27 asmlinkage
long sys_fadvise64_64(int fd
, loff_t offset
, loff_t len
, int advice
)
29 struct file
*file
= fget(fd
);
30 struct address_space
*mapping
;
31 struct backing_dev_info
*bdi
;
32 loff_t endbyte
; /* inclusive */
35 unsigned long nrpages
;
41 if (S_ISFIFO(file
->f_path
.dentry
->d_inode
->i_mode
)) {
46 mapping
= file
->f_mapping
;
47 if (!mapping
|| len
< 0) {
52 if (mapping
->a_ops
->get_xip_page
)
53 /* no bad return value, but ignore advice */
56 /* Careful about overflows. Len == 0 means "as much as possible" */
57 endbyte
= offset
+ len
;
58 if (!len
|| endbyte
< len
)
61 endbyte
--; /* inclusive */
63 bdi
= mapping
->backing_dev_info
;
66 case POSIX_FADV_NORMAL
:
67 file
->f_ra
.ra_pages
= bdi
->ra_pages
;
69 case POSIX_FADV_RANDOM
:
70 file
->f_ra
.ra_pages
= 0;
72 case POSIX_FADV_SEQUENTIAL
:
73 file
->f_ra
.ra_pages
= bdi
->ra_pages
* 2;
75 case POSIX_FADV_WILLNEED
:
76 if (!mapping
->a_ops
->readpage
) {
81 /* First and last PARTIAL page! */
82 start_index
= offset
>> PAGE_CACHE_SHIFT
;
83 end_index
= endbyte
>> PAGE_CACHE_SHIFT
;
85 /* Careful about overflow on the "+1" */
86 nrpages
= end_index
- start_index
+ 1;
90 ret
= force_page_cache_readahead(mapping
, file
,
92 max_sane_readahead(nrpages
));
96 case POSIX_FADV_NOREUSE
:
98 case POSIX_FADV_DONTNEED
:
99 if (!bdi_write_congested(mapping
->backing_dev_info
))
100 filemap_flush(mapping
);
102 /* First and last FULL page! */
103 start_index
= (offset
+(PAGE_CACHE_SIZE
-1)) >> PAGE_CACHE_SHIFT
;
104 end_index
= (endbyte
>> PAGE_CACHE_SHIFT
);
106 if (end_index
>= start_index
)
107 invalidate_mapping_pages(mapping
, start_index
,
118 #ifdef __ARCH_WANT_SYS_FADVISE64
120 asmlinkage
long sys_fadvise64(int fd
, loff_t offset
, size_t len
, int advice
)
122 return sys_fadvise64_64(fd
, offset
, len
, advice
);