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Source at commit 6c17a31f1fc515425221067cb3ece599c09dbc5d created 12 years 8 months ago. By Werner Almesberger, atusb, atben: moved from spi/ to ieee802154/; renamed atusb to spi_atusb | |
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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 | spin_lock(&file->f_lock); |
81 | file->f_mode &= ~FMODE_RANDOM; |
82 | spin_unlock(&file->f_lock); |
83 | break; |
84 | case POSIX_FADV_RANDOM: |
85 | spin_lock(&file->f_lock); |
86 | file->f_mode |= FMODE_RANDOM; |
87 | spin_unlock(&file->f_lock); |
88 | break; |
89 | case POSIX_FADV_SEQUENTIAL: |
90 | file->f_ra.ra_pages = bdi->ra_pages * 2; |
91 | spin_lock(&file->f_lock); |
92 | file->f_mode &= ~FMODE_RANDOM; |
93 | spin_unlock(&file->f_lock); |
94 | break; |
95 | case POSIX_FADV_WILLNEED: |
96 | if (!mapping->a_ops->readpage) { |
97 | ret = -EINVAL; |
98 | break; |
99 | } |
100 | |
101 | /* First and last PARTIAL page! */ |
102 | start_index = offset >> PAGE_CACHE_SHIFT; |
103 | end_index = endbyte >> PAGE_CACHE_SHIFT; |
104 | |
105 | /* Careful about overflow on the "+1" */ |
106 | nrpages = end_index - start_index + 1; |
107 | if (!nrpages) |
108 | nrpages = ~0UL; |
109 | |
110 | ret = force_page_cache_readahead(mapping, file, |
111 | start_index, |
112 | nrpages); |
113 | if (ret > 0) |
114 | ret = 0; |
115 | break; |
116 | case POSIX_FADV_NOREUSE: |
117 | break; |
118 | case POSIX_FADV_DONTNEED: |
119 | if (!bdi_write_congested(mapping->backing_dev_info)) |
120 | filemap_flush(mapping); |
121 | |
122 | /* First and last FULL page! */ |
123 | start_index = (offset+(PAGE_CACHE_SIZE-1)) >> PAGE_CACHE_SHIFT; |
124 | end_index = (endbyte >> PAGE_CACHE_SHIFT); |
125 | |
126 | if (end_index >= start_index) |
127 | invalidate_mapping_pages(mapping, start_index, |
128 | end_index); |
129 | break; |
130 | default: |
131 | ret = -EINVAL; |
132 | } |
133 | out: |
134 | fput(file); |
135 | return ret; |
136 | } |
137 | #ifdef CONFIG_HAVE_SYSCALL_WRAPPERS |
138 | asmlinkage long SyS_fadvise64_64(long fd, loff_t offset, loff_t len, long advice) |
139 | { |
140 | return SYSC_fadvise64_64((int) fd, offset, len, (int) advice); |
141 | } |
142 | SYSCALL_ALIAS(sys_fadvise64_64, SyS_fadvise64_64); |
143 | #endif |
144 | |
145 | #ifdef __ARCH_WANT_SYS_FADVISE64 |
146 | |
147 | SYSCALL_DEFINE(fadvise64)(int fd, loff_t offset, size_t len, int advice) |
148 | { |
149 | return sys_fadvise64_64(fd, offset, len, advice); |
150 | } |
151 | #ifdef CONFIG_HAVE_SYSCALL_WRAPPERS |
152 | asmlinkage long SyS_fadvise64(long fd, loff_t offset, long len, long advice) |
153 | { |
154 | return SYSC_fadvise64((int) fd, offset, (size_t)len, (int)advice); |
155 | } |
156 | SYSCALL_ALIAS(sys_fadvise64, SyS_fadvise64); |
157 | #endif |
158 | |
159 | #endif |
160 |
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