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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 | /* * mm/fadvise.c * * Copyright (C) 2002, Linus Torvalds * * 11Jan2003 Andrew Morton * Initial version. */ #include <linux/kernel.h> #include <linux/file.h> #include <linux/fs.h> #include <linux/mm.h> #include <linux/pagemap.h> #include <linux/backing-dev.h> #include <linux/pagevec.h> #include <linux/fadvise.h> #include <linux/writeback.h> #include <linux/syscalls.h> #include <asm/unistd.h> /* * POSIX_FADV_WILLNEED could set PG_Referenced, and POSIX_FADV_NOREUSE could * deactivate the pages and clear PG_Referenced. */ SYSCALL_DEFINE(fadvise64_64)(int fd, loff_t offset, loff_t len, int advice) { struct file *file = fget(fd); struct address_space *mapping; struct backing_dev_info *bdi; loff_t endbyte; /* inclusive */ pgoff_t start_index; pgoff_t end_index; unsigned long nrpages; int ret = 0; if (!file) return -EBADF; if (S_ISFIFO(file->f_path.dentry->d_inode->i_mode)) { ret = -ESPIPE; goto out; } mapping = file->f_mapping; if (!mapping || len < 0) { ret = -EINVAL; goto out; } if (mapping->a_ops->get_xip_mem) { switch (advice) { case POSIX_FADV_NORMAL: case POSIX_FADV_RANDOM: case POSIX_FADV_SEQUENTIAL: case POSIX_FADV_WILLNEED: case POSIX_FADV_NOREUSE: case POSIX_FADV_DONTNEED: /* no bad return value, but ignore advice */ break; default: ret = -EINVAL; } goto out; } /* Careful about overflows. Len == 0 means "as much as possible" */ endbyte = offset + len; if (!len || endbyte < len) endbyte = -1; else endbyte--; /* inclusive */ bdi = mapping->backing_dev_info; switch (advice) { case POSIX_FADV_NORMAL: file->f_ra.ra_pages = bdi->ra_pages; spin_lock(&file->f_lock); file->f_mode &= ~FMODE_RANDOM; spin_unlock(&file->f_lock); break; case POSIX_FADV_RANDOM: spin_lock(&file->f_lock); file->f_mode |= FMODE_RANDOM; spin_unlock(&file->f_lock); break; case POSIX_FADV_SEQUENTIAL: file->f_ra.ra_pages = bdi->ra_pages * 2; spin_lock(&file->f_lock); file->f_mode &= ~FMODE_RANDOM; spin_unlock(&file->f_lock); break; case POSIX_FADV_WILLNEED: if (!mapping->a_ops->readpage) { ret = -EINVAL; break; } /* First and last PARTIAL page! */ start_index = offset >> PAGE_CACHE_SHIFT; end_index = endbyte >> PAGE_CACHE_SHIFT; /* Careful about overflow on the "+1" */ nrpages = end_index - start_index + 1; if (!nrpages) nrpages = ~0UL; ret = force_page_cache_readahead(mapping, file, start_index, nrpages); if (ret > 0) ret = 0; break; case POSIX_FADV_NOREUSE: break; case POSIX_FADV_DONTNEED: if (!bdi_write_congested(mapping->backing_dev_info)) filemap_flush(mapping); /* First and last FULL page! */ start_index = (offset+(PAGE_CACHE_SIZE-1)) >> PAGE_CACHE_SHIFT; end_index = (endbyte >> PAGE_CACHE_SHIFT); if (end_index >= start_index) invalidate_mapping_pages(mapping, start_index, end_index); break; default: ret = -EINVAL; } out: fput(file); return ret; } #ifdef CONFIG_HAVE_SYSCALL_WRAPPERS asmlinkage long SyS_fadvise64_64(long fd, loff_t offset, loff_t len, long advice) { return SYSC_fadvise64_64((int) fd, offset, len, (int) advice); } SYSCALL_ALIAS(sys_fadvise64_64, SyS_fadvise64_64); #endif #ifdef __ARCH_WANT_SYS_FADVISE64 SYSCALL_DEFINE(fadvise64)(int fd, loff_t offset, size_t len, int advice) { return sys_fadvise64_64(fd, offset, len, advice); } #ifdef CONFIG_HAVE_SYSCALL_WRAPPERS asmlinkage long SyS_fadvise64(long fd, loff_t offset, long len, long advice) { return SYSC_fadvise64((int) fd, offset, (size_t)len, (int)advice); } SYSCALL_ALIAS(sys_fadvise64, SyS_fadvise64); #endif #endif |