diff options
Diffstat (limited to 'mm/fadvise.c')
-rw-r--r-- | mm/fadvise.c | 159 |
1 files changed, 159 insertions, 0 deletions
diff --git a/mm/fadvise.c b/mm/fadvise.c new file mode 100644 index 00000000..8d723c9e --- /dev/null +++ b/mm/fadvise.c @@ -0,0 +1,159 @@ +/* + * 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 |