mirror of
https://github.com/torvalds/linux.git
synced 2024-12-23 11:21:33 +00:00
126 lines
2.8 KiB
C
126 lines
2.8 KiB
C
/*
|
|
* mmap.c
|
|
*
|
|
* Copyright (C) 1995, 1996 by Volker Lendecke
|
|
* Modified 1997 Peter Waltenberg, Bill Hawes, David Woodhouse for 2.1 dcache
|
|
*
|
|
*/
|
|
|
|
#include <linux/stat.h>
|
|
#include <linux/time.h>
|
|
#include <linux/kernel.h>
|
|
#include <linux/gfp.h>
|
|
#include <linux/mm.h>
|
|
#include <linux/shm.h>
|
|
#include <linux/errno.h>
|
|
#include <linux/mman.h>
|
|
#include <linux/string.h>
|
|
#include <linux/fcntl.h>
|
|
#include <linux/memcontrol.h>
|
|
|
|
#include <asm/uaccess.h>
|
|
|
|
#include "ncp_fs.h"
|
|
|
|
/*
|
|
* Fill in the supplied page for mmap
|
|
* XXX: how are we excluding truncate/invalidate here? Maybe need to lock
|
|
* page?
|
|
*/
|
|
static int ncp_file_mmap_fault(struct vm_area_struct *area,
|
|
struct vm_fault *vmf)
|
|
{
|
|
struct inode *inode = file_inode(area->vm_file);
|
|
char *pg_addr;
|
|
unsigned int already_read;
|
|
unsigned int count;
|
|
int bufsize;
|
|
int pos; /* XXX: loff_t ? */
|
|
|
|
/*
|
|
* ncpfs has nothing against high pages as long
|
|
* as recvmsg and memset works on it
|
|
*/
|
|
vmf->page = alloc_page(GFP_HIGHUSER);
|
|
if (!vmf->page)
|
|
return VM_FAULT_OOM;
|
|
pg_addr = kmap(vmf->page);
|
|
pos = vmf->pgoff << PAGE_SHIFT;
|
|
|
|
count = PAGE_SIZE;
|
|
/* what we can read in one go */
|
|
bufsize = NCP_SERVER(inode)->buffer_size;
|
|
|
|
already_read = 0;
|
|
if (ncp_make_open(inode, O_RDONLY) >= 0) {
|
|
while (already_read < count) {
|
|
int read_this_time;
|
|
int to_read;
|
|
|
|
to_read = bufsize - (pos % bufsize);
|
|
|
|
to_read = min_t(unsigned int, to_read, count - already_read);
|
|
|
|
if (ncp_read_kernel(NCP_SERVER(inode),
|
|
NCP_FINFO(inode)->file_handle,
|
|
pos, to_read,
|
|
pg_addr + already_read,
|
|
&read_this_time) != 0) {
|
|
read_this_time = 0;
|
|
}
|
|
pos += read_this_time;
|
|
already_read += read_this_time;
|
|
|
|
if (read_this_time < to_read) {
|
|
break;
|
|
}
|
|
}
|
|
ncp_inode_close(inode);
|
|
|
|
}
|
|
|
|
if (already_read < PAGE_SIZE)
|
|
memset(pg_addr + already_read, 0, PAGE_SIZE - already_read);
|
|
flush_dcache_page(vmf->page);
|
|
kunmap(vmf->page);
|
|
|
|
/*
|
|
* If I understand ncp_read_kernel() properly, the above always
|
|
* fetches from the network, here the analogue of disk.
|
|
* -- nyc
|
|
*/
|
|
count_vm_event(PGMAJFAULT);
|
|
mem_cgroup_count_vm_event(area->vm_mm, PGMAJFAULT);
|
|
return VM_FAULT_MAJOR;
|
|
}
|
|
|
|
static const struct vm_operations_struct ncp_file_mmap =
|
|
{
|
|
.fault = ncp_file_mmap_fault,
|
|
};
|
|
|
|
|
|
/* This is used for a general mmap of a ncp file */
|
|
int ncp_mmap(struct file *file, struct vm_area_struct *vma)
|
|
{
|
|
struct inode *inode = file_inode(file);
|
|
|
|
ncp_dbg(1, "called\n");
|
|
|
|
if (!ncp_conn_valid(NCP_SERVER(inode)))
|
|
return -EIO;
|
|
|
|
/* only PAGE_COW or read-only supported now */
|
|
if (vma->vm_flags & VM_SHARED)
|
|
return -EINVAL;
|
|
/* we do not support files bigger than 4GB... We eventually
|
|
supports just 4GB... */
|
|
if (vma_pages(vma) + vma->vm_pgoff
|
|
> (1U << (32 - PAGE_SHIFT)))
|
|
return -EFBIG;
|
|
|
|
vma->vm_ops = &ncp_file_mmap;
|
|
file_accessed(file);
|
|
return 0;
|
|
}
|