4 * Copyright (C) 2002, Linus Torvalds
6 * 11Jan2003 Andrew Morton
10 #include <linux/kernel.h>
11 #include <linux/file.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 #include <linux/swap.h>
22 #include <asm/unistd.h>
25 * POSIX_FADV_WILLNEED could set PG_Referenced, and POSIX_FADV_NOREUSE could
26 * deactivate the pages and clear PG_Referenced.
28 SYSCALL_DEFINE(fadvise64_64)(int fd, loff_t offset, loff_t len, int advice)
30 struct file *file = fget(fd);
31 struct address_space *mapping;
32 struct backing_dev_info *bdi;
33 loff_t endbyte; /* inclusive */
36 unsigned long nrpages;
42 if (S_ISFIFO(file->f_path.dentry->d_inode->i_mode)) {
47 mapping = file->f_mapping;
48 if (!mapping || len < 0) {
53 if (mapping->a_ops->get_xip_mem) {
55 case POSIX_FADV_NORMAL:
56 case POSIX_FADV_RANDOM:
57 case POSIX_FADV_SEQUENTIAL:
58 case POSIX_FADV_WILLNEED:
59 case POSIX_FADV_NOREUSE:
60 case POSIX_FADV_DONTNEED:
61 /* no bad return value, but ignore advice */
69 /* Careful about overflows. Len == 0 means "as much as possible" */
70 endbyte = offset + len;
71 if (!len || endbyte < len)
74 endbyte--; /* inclusive */
76 bdi = mapping->backing_dev_info;
79 case POSIX_FADV_NORMAL:
80 file->f_ra.ra_pages = bdi->ra_pages;
81 spin_lock(&file->f_lock);
82 file->f_mode &= ~FMODE_RANDOM;
83 spin_unlock(&file->f_lock);
85 case POSIX_FADV_RANDOM:
86 spin_lock(&file->f_lock);
87 file->f_mode |= FMODE_RANDOM;
88 spin_unlock(&file->f_lock);
90 case POSIX_FADV_SEQUENTIAL:
91 file->f_ra.ra_pages = bdi->ra_pages * 2;
92 spin_lock(&file->f_lock);
93 file->f_mode &= ~FMODE_RANDOM;
94 spin_unlock(&file->f_lock);
96 case POSIX_FADV_WILLNEED:
97 if (!mapping->a_ops->readpage) {
102 /* First and last PARTIAL page! */
103 start_index = offset >> PAGE_CACHE_SHIFT;
104 end_index = endbyte >> PAGE_CACHE_SHIFT;
106 /* Careful about overflow on the "+1" */
107 nrpages = end_index - start_index + 1;
111 ret = force_page_cache_readahead(mapping, file,
117 case POSIX_FADV_NOREUSE:
119 case POSIX_FADV_DONTNEED:
120 if (!bdi_write_congested(mapping->backing_dev_info))
121 filemap_flush(mapping);
123 /* First and last FULL page! */
124 start_index = (offset+(PAGE_CACHE_SIZE-1)) >> PAGE_CACHE_SHIFT;
125 end_index = (endbyte >> PAGE_CACHE_SHIFT);
127 if (end_index >= start_index) {
128 unsigned long count = invalidate_mapping_pages(mapping,
129 start_index, end_index);
132 * If fewer pages were invalidated than expected then
133 * it is possible that some of the pages were on
134 * a per-cpu pagevec for a remote CPU. Drain all
135 * pagevecs and try again.
137 if (count < (end_index - start_index + 1)) {
139 invalidate_mapping_pages(mapping, start_index,
151 #ifdef CONFIG_HAVE_SYSCALL_WRAPPERS
152 asmlinkage long SyS_fadvise64_64(long fd, loff_t offset, loff_t len, long advice)
154 return SYSC_fadvise64_64((int) fd, offset, len, (int) advice);
156 SYSCALL_ALIAS(sys_fadvise64_64, SyS_fadvise64_64);
159 #ifdef __ARCH_WANT_SYS_FADVISE64
161 SYSCALL_DEFINE(fadvise64)(int fd, loff_t offset, size_t len, int advice)
163 return sys_fadvise64_64(fd, offset, len, advice);
165 #ifdef CONFIG_HAVE_SYSCALL_WRAPPERS
166 asmlinkage long SyS_fadvise64(long fd, loff_t offset, long len, long advice)
168 return SYSC_fadvise64((int) fd, offset, (size_t)len, (int)advice);
170 SYSCALL_ALIAS(sys_fadvise64, SyS_fadvise64);