mm: move readahead syscall to mm/readahead.c

It is better to define readahead(2) in mm/readahead.c than in
mm/filemap.c.

Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com>
Cc: Fengguang Wu <fengguang.wu@intel.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 0 insertions, 39 deletions

diff --git a/mm/filemap.c b/mm/filemap.c
index 79c4b2b0b14e..64b48f934b89 100644
--- a/mm/filemap.c
+++ b/mm/filemap.c
@@ -29,7 +29,6 @@
 #include <linux/pagevec.h>
 #include <linux/blkdev.h>
 #include <linux/security.h>
-#include <linux/syscalls.h>
 #include <linux/cpuset.h>
 #include <linux/hardirq.h> /* for BUG_ON(!in_atomic()) only */
 #include <linux/memcontrol.h>
@@ -1478,44 +1477,6 @@ out:
 }
 EXPORT_SYMBOL(generic_file_aio_read);
 
-static ssize_t
-do_readahead(struct address_space *mapping, struct file *filp,
-             pgoff_t index, unsigned long nr)
-{
-        if (!mapping || !mapping->a_ops || !mapping->a_ops->readpage)
-                return -EINVAL;
-
-        force_page_cache_readahead(mapping, filp, index, nr);
-        return 0;
-}
-
-SYSCALL_DEFINE(readahead)(int fd, loff_t offset, size_t count)
-{
-        ssize_t ret;
-        struct file *file;
-
-        ret = -EBADF;
-        file = fget(fd);
-        if (file) {
-                if (file->f_mode & FMODE_READ) {
-                        struct address_space *mapping = file->f_mapping;
-                        pgoff_t start = offset >> PAGE_CACHE_SHIFT;
-                        pgoff_t end = (offset + count - 1) >> PAGE_CACHE_SHIFT;
-                        unsigned long len = end - start + 1;
-                        ret = do_readahead(mapping, file, start, len);
-                }
-                fput(file);
-        }
-        return ret;
-}
-#ifdef CONFIG_HAVE_SYSCALL_WRAPPERS
-asmlinkage long SyS_readahead(long fd, loff_t offset, long count)
-{
-        return SYSC_readahead((int) fd, offset, (size_t) count);
-}
-SYSCALL_ALIAS(sys_readahead, SyS_readahead);
-#endif
-
 #ifdef CONFIG_MMU
 /**
  * page_cache_read - adds requested page to the page cache if not already there