projects / mirror_ubuntu-zesty-kernel.git / blame
| Commit | Line | Data |
|---|---|---|
| 1da177e4 LT |
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 | mapping = file->f_mapping; | |
| 41 | if (!mapping || len < 0) { | |
| 42 | ret = -EINVAL; | |
| 43 | goto out; | |
| 44 | } | |
| 45 | ||
| fe77ba6f CO |
46 | if (mapping->a_ops->get_xip_page) |
| 47 | /* no bad return value, but ignore advice */ | |
| 48 | goto out; | |
| 49 | ||
| 1da177e4 LT |
50 | /* Careful about overflows. Len == 0 means "as much as possible" */ |
| 51 | endbyte = offset + len; | |
| 52 | if (!len || endbyte < len) | |
| 53 | endbyte = -1; | |
| 54 | ||
| 55 | bdi = mapping->backing_dev_info; | |
| 56 | ||
| 57 | switch (advice) { | |
| 58 | case POSIX_FADV_NORMAL: | |
| 59 | file->f_ra.ra_pages = bdi->ra_pages; | |
| 60 | break; | |
| 61 | case POSIX_FADV_RANDOM: | |
| 62 | file->f_ra.ra_pages = 0; | |
| 63 | break; | |
| 64 | case POSIX_FADV_SEQUENTIAL: | |
| 65 | file->f_ra.ra_pages = bdi->ra_pages * 2; | |
| 66 | break; | |
| 67 | case POSIX_FADV_WILLNEED: | |
| 68 | case POSIX_FADV_NOREUSE: | |
| 69 | if (!mapping->a_ops->readpage) { | |
| 70 | ret = -EINVAL; | |
| 71 | break; | |
| 72 | } | |
| 73 | ||
| 74 | /* First and last PARTIAL page! */ | |
| 75 | start_index = offset >> PAGE_CACHE_SHIFT; | |
| 76 | end_index = (endbyte-1) >> PAGE_CACHE_SHIFT; | |
| 77 | ||
| 78 | /* Careful about overflow on the "+1" */ | |
| 79 | nrpages = end_index - start_index + 1; | |
| 80 | if (!nrpages) | |
| 81 | nrpages = ~0UL; | |
| 82 | ||
| 83 | ret = force_page_cache_readahead(mapping, file, | |
| 84 | start_index, | |
| 85 | max_sane_readahead(nrpages)); | |
| 86 | if (ret > 0) | |
| 87 | ret = 0; | |
| 88 | break; | |
| 89 | case POSIX_FADV_DONTNEED: | |
| 90 | if (!bdi_write_congested(mapping->backing_dev_info)) | |
| 91 | filemap_flush(mapping); | |
| 92 | ||
| 93 | /* First and last FULL page! */ | |
| 94 | start_index = (offset + (PAGE_CACHE_SIZE-1)) >> PAGE_CACHE_SHIFT; | |
| 95 | end_index = (endbyte >> PAGE_CACHE_SHIFT); | |
| 96 | ||
| 97 | if (end_index > start_index) | |
| 98 | invalidate_mapping_pages(mapping, start_index, end_index-1); | |
| 99 | break; | |
| 100 | default: | |
| 101 | ret = -EINVAL; | |
| 102 | } | |
| 103 | out: | |
| 104 | fput(file); | |
| 105 | return ret; | |
| 106 | } | |
| 107 | ||
| 108 | #ifdef __ARCH_WANT_SYS_FADVISE64 | |
| 109 | ||
| 110 | asmlinkage long sys_fadvise64(int fd, loff_t offset, size_t len, int advice) | |
| 111 | { | |
| 112 | return sys_fadvise64_64(fd, offset, len, advice); | |
| 113 | } | |
| 114 | ||
| 115 | #endif |