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Commit 782182e5 authored by Cong Wang's avatar Cong Wang Committed by Linus Torvalds
Browse files

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: default avatarCong Wang <xiyou.wangcong@gmail.com>
Cc: Fengguang Wu <fengguang.wu@intel.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 4fb5ef08

mm/filemap.c

+0 −39
Original line number Diff line number Diff line
@@ -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 @@ generic_file_aio_read(struct kiocb *iocb, const struct iovec *iov, 
}

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

mm/readahead.c

+40 −0
Original line number Diff line number Diff line
@@ -17,6 +17,8 @@ 
#include <linux/task_io_accounting_ops.h>

#include <linux/pagevec.h>

#include <linux/pagemap.h>

#include <linux/syscalls.h>

#include <linux/file.h>



/*

 * Initialise a struct file's readahead state.  Assumes that the caller has
@@ -562,3 +564,41 @@ page_cache_async_readahead(struct address_space *mapping, 
	ondemand_readahead(mapping, ra, filp, true, offset, req_size);

}

EXPORT_SYMBOL_GPL(page_cache_async_readahead);



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