ia64/linux-2.6.18-xen.hg

view mm/fadvise.c @ 749:2892ca2b9c17

linux/x86: cleanup IO-APIC code

- get 32-bit code in sync with 64-bit wrt ExtINT pin detection being
unnecessary
- eliminate build warnings resulting from c/s 725

Signed-off-by: Jan Beulich <jbeulich@novell.com>
author Keir Fraser <keir.fraser@citrix.com>
date Fri Nov 28 13:31:21 2008 +0000 (2008-11-28)
parents 831230e53067
children
line source
1 /*
2 * mm/fadvise.c
3 *
4 * Copyright (C) 2002, Linus Torvalds
5 *
6 * 11Jan2003 akpm@digeo.com
7 * Initial version.
8 */
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>
21 #include <asm/unistd.h>
23 /*
24 * POSIX_FADV_WILLNEED could set PG_Referenced, and POSIX_FADV_NOREUSE could
25 * deactivate the pages and clear PG_Referenced.
26 */
27 asmlinkage long sys_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;
38 if (!file)
39 return -EBADF;
41 if (S_ISFIFO(file->f_dentry->d_inode->i_mode)) {
42 ret = -ESPIPE;
43 goto out;
44 }
46 mapping = file->f_mapping;
47 if (!mapping || len < 0) {
48 ret = -EINVAL;
49 goto out;
50 }
52 if (mapping->a_ops->get_xip_page)
53 /* no bad return value, but ignore advice */
54 goto out;
56 /* Careful about overflows. Len == 0 means "as much as possible" */
57 endbyte = offset + len;
58 if (!len || endbyte < len)
59 endbyte = -1;
60 else
61 endbyte--; /* inclusive */
63 bdi = mapping->backing_dev_info;
65 switch (advice) {
66 case POSIX_FADV_NORMAL:
67 file->f_ra.ra_pages = bdi->ra_pages;
68 break;
69 case POSIX_FADV_RANDOM:
70 file->f_ra.ra_pages = 0;
71 break;
72 case POSIX_FADV_SEQUENTIAL:
73 file->f_ra.ra_pages = bdi->ra_pages * 2;
74 break;
75 case POSIX_FADV_WILLNEED:
76 if (!mapping->a_ops->readpage) {
77 ret = -EINVAL;
78 break;
79 }
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;
87 if (!nrpages)
88 nrpages = ~0UL;
90 ret = force_page_cache_readahead(mapping, file,
91 start_index,
92 max_sane_readahead(nrpages));
93 if (ret > 0)
94 ret = 0;
95 break;
96 case POSIX_FADV_NOREUSE:
97 break;
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,
108 end_index);
109 break;
110 default:
111 ret = -EINVAL;
112 }
113 out:
114 fput(file);
115 return ret;
116 }
118 #ifdef __ARCH_WANT_SYS_FADVISE64
120 asmlinkage long sys_fadvise64(int fd, loff_t offset, size_t len, int advice)
121 {
122 return sys_fadvise64_64(fd, offset, len, advice);
123 }
125 #endif