[SPARC64]: Deal with PTE layout differences in SUN4V.
[linux-2.6] / mm / fadvise.c
1 /*
2  * mm/fadvise.c
3  *
4  * Copyright (C) 2002, Linus Torvalds
5  *
6  * 11Jan2003    akpm@digeo.com
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/syscalls.h>
19
20 #include <asm/unistd.h>
21
22 /*
23  * POSIX_FADV_WILLNEED could set PG_Referenced, and POSIX_FADV_NOREUSE could
24  * deactivate the pages and clear PG_Referenced.
25  */
26 asmlinkage long sys_fadvise64_64(int fd, loff_t offset, loff_t len, int advice)
27 {
28         struct file *file = fget(fd);
29         struct address_space *mapping;
30         struct backing_dev_info *bdi;
31         loff_t endbyte;
32         pgoff_t start_index;
33         pgoff_t end_index;
34         unsigned long nrpages;
35         int ret = 0;
36
37         if (!file)
38                 return -EBADF;
39
40         if (S_ISFIFO(file->f_dentry->d_inode->i_mode)) {
41                 ret = -ESPIPE;
42                 goto out;
43         }
44
45         mapping = file->f_mapping;
46         if (!mapping || len < 0) {
47                 ret = -EINVAL;
48                 goto out;
49         }
50
51         if (mapping->a_ops->get_xip_page)
52                 /* no bad return value, but ignore advice */
53                 goto out;
54
55         /* Careful about overflows. Len == 0 means "as much as possible" */
56         endbyte = offset + len;
57         if (!len || endbyte < len)
58                 endbyte = -1;
59
60         bdi = mapping->backing_dev_info;
61
62         switch (advice) {
63         case POSIX_FADV_NORMAL:
64                 file->f_ra.ra_pages = bdi->ra_pages;
65                 break;
66         case POSIX_FADV_RANDOM:
67                 file->f_ra.ra_pages = 0;
68                 break;
69         case POSIX_FADV_SEQUENTIAL:
70                 file->f_ra.ra_pages = bdi->ra_pages * 2;
71                 break;
72         case POSIX_FADV_WILLNEED:
73         case POSIX_FADV_NOREUSE:
74                 if (!mapping->a_ops->readpage) {
75                         ret = -EINVAL;
76                         break;
77                 }
78
79                 /* First and last PARTIAL page! */
80                 start_index = offset >> PAGE_CACHE_SHIFT;
81                 end_index = (endbyte-1) >> PAGE_CACHE_SHIFT;
82
83                 /* Careful about overflow on the "+1" */
84                 nrpages = end_index - start_index + 1;
85                 if (!nrpages)
86                         nrpages = ~0UL;
87                 
88                 ret = force_page_cache_readahead(mapping, file,
89                                 start_index,
90                                 max_sane_readahead(nrpages));
91                 if (ret > 0)
92                         ret = 0;
93                 break;
94         case POSIX_FADV_DONTNEED:
95                 if (!bdi_write_congested(mapping->backing_dev_info))
96                         filemap_flush(mapping);
97
98                 /* First and last FULL page! */
99                 start_index = (offset + (PAGE_CACHE_SIZE-1)) >> PAGE_CACHE_SHIFT;
100                 end_index = (endbyte >> PAGE_CACHE_SHIFT);
101
102                 if (end_index > start_index)
103                         invalidate_mapping_pages(mapping, start_index, end_index-1);
104                 break;
105         default:
106                 ret = -EINVAL;
107         }
108 out:
109         fput(file);
110         return ret;
111 }
112
113 #ifdef __ARCH_WANT_SYS_FADVISE64
114
115 asmlinkage long sys_fadvise64(int fd, loff_t offset, size_t len, int advice)
116 {
117         return sys_fadvise64_64(fd, offset, len, advice);
118 }
119
120 #endif