4 * Copyright (C) 2002, Linus Torvalds
6 * 11Jan2003 akpm@digeo.com
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>
19 #include <asm/unistd.h>
22 * POSIX_FADV_WILLNEED could set PG_Referenced, and POSIX_FADV_NOREUSE could
23 * deactivate the pages and clear PG_Referenced.
25 asmlinkage long sys_fadvise64_64(int fd, loff_t offset, loff_t len, int advice)
27 struct file *file = fget(fd);
28 struct address_space *mapping;
29 struct backing_dev_info *bdi;
33 unsigned long nrpages;
39 mapping = file->f_mapping;
40 if (!mapping || len < 0) {
45 /* Careful about overflows. Len == 0 means "as much as possible" */
46 endbyte = offset + len;
47 if (!len || endbyte < len)
50 bdi = mapping->backing_dev_info;
53 case POSIX_FADV_NORMAL:
54 file->f_ra.ra_pages = bdi->ra_pages;
56 case POSIX_FADV_RANDOM:
57 file->f_ra.ra_pages = 0;
59 case POSIX_FADV_SEQUENTIAL:
60 file->f_ra.ra_pages = bdi->ra_pages * 2;
62 case POSIX_FADV_WILLNEED:
63 case POSIX_FADV_NOREUSE:
64 if (!mapping->a_ops->readpage) {
69 /* First and last PARTIAL page! */
70 start_index = offset >> PAGE_CACHE_SHIFT;
71 end_index = (endbyte-1) >> PAGE_CACHE_SHIFT;
73 /* Careful about overflow on the "+1" */
74 nrpages = end_index - start_index + 1;
78 ret = force_page_cache_readahead(mapping, file,
80 max_sane_readahead(nrpages));
84 case POSIX_FADV_DONTNEED:
85 if (!bdi_write_congested(mapping->backing_dev_info))
86 filemap_flush(mapping);
88 /* First and last FULL page! */
89 start_index = (offset + (PAGE_CACHE_SIZE-1)) >> PAGE_CACHE_SHIFT;
90 end_index = (endbyte >> PAGE_CACHE_SHIFT);
92 if (end_index > start_index)
93 invalidate_mapping_pages(mapping, start_index, end_index-1);
103 #ifdef __ARCH_WANT_SYS_FADVISE64
105 asmlinkage long sys_fadvise64(int fd, loff_t offset, size_t len, int advice)
107 return sys_fadvise64_64(fd, offset, len, advice);