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
|
This page was automatically generated by the
LXR engine.
|