root/fs/ncpfs/mmap.c

DEFINITIONS

1. ncp_file_mmap_fault
2. ncp_mmap

/*
 *  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/mm.h>
#include <linux/shm.h>
#include <linux/errno.h>
#include <linux/mman.h>
#include <linux/string.h>
#include <linux/slab.h>
#include <linux/fcntl.h>
#include <linux/ncp_fs.h>

#include "ncplib_kernel.h"
#include <asm/uaccess.h>
#include <asm/system.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 file *file = area->vm_file;
        struct dentry *dentry = file->f_path.dentry;
        struct inode *inode = dentry->d_inode;
        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.
         * -- wli
         */
        count_vm_event(PGMAJFAULT);
        return VM_FAULT_MAJOR;
}

static 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->f_path.dentry->d_inode;
        
        DPRINTK("ncp_mmap: 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->vm_end - vma->vm_start) >> PAGE_SHIFT) + vma->vm_pgoff 
           > (1U << (32 - PAGE_SHIFT)))
                return -EFBIG;

        vma->vm_ops = &ncp_file_mmap;
        file_accessed(file);
        return 0;
}