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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>
This commit is contained in:
Cong Wang 2012-05-29 15:06:43 -07:00 committed by Linus Torvalds
parent 4fb5ef089b
commit 782182e53a
2 changed files with 40 additions and 39 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

39
mm/filemap.c
View File

@ -29,7 +29,6 @@
#include <linux/pagevec.h> #include <linux/pagevec.h>
#include <linux/blkdev.h> #include <linux/blkdev.h>
#include <linux/security.h> #include <linux/security.h>
#include <linux/syscalls.h>
#include <linux/cpuset.h> #include <linux/cpuset.h>
#include <linux/hardirq.h> /* for BUG_ON(!in_atomic()) only */ #include <linux/hardirq.h> /* for BUG_ON(!in_atomic()) only */
#include <linux/memcontrol.h> #include <linux/memcontrol.h>
@ -1478,44 +1477,6 @@ out:
} }
EXPORT_SYMBOL(generic_file_aio_read); 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 #ifdef CONFIG_MMU
/** /**
* page_cache_read - adds requested page to the page cache if not already there * page_cache_read - adds requested page to the page cache if not already there

40
mm/readahead.c
View File

@ -17,6 +17,8 @@
#include <linux/task_io_accounting_ops.h> #include <linux/task_io_accounting_ops.h>
#include <linux/pagevec.h> #include <linux/pagevec.h>
#include <linux/pagemap.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 * 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); ondemand_readahead(mapping, ra, filp, true, offset, req_size);
} }
EXPORT_SYMBOL_GPL(page_cache_async_readahead); 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