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1 | /* |
2 | * mm/fadvise.c |
3 | * |
4 | * Copyright (C) 2002, Linus Torvalds |
5 | * |
6 | * 11Jan2003 Andrew Morton |
7 | * Initial version. |
8 | */ |
9 | |
10 | #include <linux/kernel.h> |
11 | #include <linux/file.h> |
12 | #include <linux/fs.h> |
13 | #include <linux/mm.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> |
20 | |
21 | #include <asm/unistd.h> |
22 | |
23 | /* |
24 | * POSIX_FADV_WILLNEED could set PG_Referenced, and POSIX_FADV_NOREUSE could |
25 | * deactivate the pages and clear PG_Referenced. |
26 | */ |
27 | SYSCALL_DEFINE(fadvise64_64)(int fd, loff_t offset, loff_t len, int advice) |
28 | { |
29 | struct file *file = fget(fd); |
30 | struct address_space *mapping; |
31 | struct backing_dev_info *bdi; |
32 | loff_t endbyte; /* inclusive */ |
33 | pgoff_t start_index; |
34 | pgoff_t end_index; |
35 | unsigned long nrpages; |
36 | int ret = 0; |
37 | |
38 | if (!file) |
39 | return -EBADF; |
40 | |
41 | if (S_ISFIFO(file->f_path.dentry->d_inode->i_mode)) { |
42 | ret = -ESPIPE; |
43 | goto out; |
44 | } |
45 | |
46 | mapping = file->f_mapping; |
47 | if (!mapping || len < 0) { |
48 | ret = -EINVAL; |
49 | goto out; |
50 | } |
51 | |
52 | if (mapping->a_ops->get_xip_mem) { |
53 | switch (advice) { |
54 | case POSIX_FADV_NORMAL: |
55 | case POSIX_FADV_RANDOM: |
56 | case POSIX_FADV_SEQUENTIAL: |
57 | case POSIX_FADV_WILLNEED: |
58 | case POSIX_FADV_NOREUSE: |
59 | case POSIX_FADV_DONTNEED: |
60 | /* no bad return value, but ignore advice */ |
61 | break; |
62 | default: |
63 | ret = -EINVAL; |
64 | } |
65 | goto out; |
66 | } |
67 | |
68 | /* Careful about overflows. Len == 0 means "as much as possible" */ |
69 | endbyte = offset + len; |
70 | if (!len || endbyte < len) |
71 | endbyte = -1; |
72 | else |
73 | endbyte--; /* inclusive */ |
74 | |
75 | bdi = mapping->backing_dev_info; |
76 | |
77 | switch (advice) { |
78 | case POSIX_FADV_NORMAL: |
79 | file->f_ra.ra_pages = bdi->ra_pages; |
80 | break; |
81 | case POSIX_FADV_RANDOM: |
82 | file->f_ra.ra_pages = 0; |
83 | break; |
84 | case POSIX_FADV_SEQUENTIAL: |
85 | file->f_ra.ra_pages = bdi->ra_pages * 2; |
86 | break; |
87 | case POSIX_FADV_WILLNEED: |
88 | if (!mapping->a_ops->readpage) { |
89 | ret = -EINVAL; |
90 | break; |
91 | } |
92 | |
93 | /* First and last PARTIAL page! */ |
94 | start_index = offset >> PAGE_CACHE_SHIFT; |
95 | end_index = endbyte >> PAGE_CACHE_SHIFT; |
96 | |
97 | /* Careful about overflow on the "+1" */ |
98 | nrpages = end_index - start_index + 1; |
99 | if (!nrpages) |
100 | nrpages = ~0UL; |
101 | |
102 | ret = force_page_cache_readahead(mapping, file, |
103 | start_index, |
104 | nrpages); |
105 | if (ret > 0) |
106 | ret = 0; |
107 | break; |
108 | case POSIX_FADV_NOREUSE: |
109 | break; |
110 | case POSIX_FADV_DONTNEED: |
111 | if (!bdi_write_congested(mapping->backing_dev_info)) |
112 | filemap_flush(mapping); |
113 | |
114 | /* First and last FULL page! */ |
115 | start_index = (offset+(PAGE_CACHE_SIZE-1)) >> PAGE_CACHE_SHIFT; |
116 | end_index = (endbyte >> PAGE_CACHE_SHIFT); |
117 | |
118 | if (end_index >= start_index) |
119 | invalidate_mapping_pages(mapping, start_index, |
120 | end_index); |
121 | break; |
122 | default: |
123 | ret = -EINVAL; |
124 | } |
125 | out: |
126 | fput(file); |
127 | return ret; |
128 | } |
129 | #ifdef CONFIG_HAVE_SYSCALL_WRAPPERS |
130 | asmlinkage long SyS_fadvise64_64(long fd, loff_t offset, loff_t len, long advice) |
131 | { |
132 | return SYSC_fadvise64_64((int) fd, offset, len, (int) advice); |
133 | } |
134 | SYSCALL_ALIAS(sys_fadvise64_64, SyS_fadvise64_64); |
135 | #endif |
136 | |
137 | #ifdef __ARCH_WANT_SYS_FADVISE64 |
138 | |
139 | SYSCALL_DEFINE(fadvise64)(int fd, loff_t offset, size_t len, int advice) |
140 | { |
141 | return sys_fadvise64_64(fd, offset, len, advice); |
142 | } |
143 | #ifdef CONFIG_HAVE_SYSCALL_WRAPPERS |
144 | asmlinkage long SyS_fadvise64(long fd, loff_t offset, long len, long advice) |
145 | { |
146 | return SYSC_fadvise64((int) fd, offset, (size_t)len, (int)advice); |
147 | } |
148 | SYSCALL_ALIAS(sys_fadvise64, SyS_fadvise64); |
149 | #endif |
150 | |
151 | #endif |
152 |
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