blob: 52d60c3d8996210dac419106b1dc7862a6fb8856 [file] [log] [blame]
Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
2 * mmap.c
3 *
4 * Copyright (C) 1995, 1996 by Volker Lendecke
5 * Modified 1997 Peter Waltenberg, Bill Hawes, David Woodhouse for 2.1 dcache
6 *
7 */
8
9#include <linux/stat.h>
10#include <linux/time.h>
11#include <linux/kernel.h>
12#include <linux/mm.h>
13#include <linux/shm.h>
14#include <linux/errno.h>
15#include <linux/mman.h>
16#include <linux/string.h>
17#include <linux/slab.h>
18#include <linux/fcntl.h>
19#include <linux/ncp_fs.h>
20
21#include "ncplib_kernel.h"
22#include <asm/uaccess.h>
23#include <asm/system.h>
24
25/*
26 * Fill in the supplied page for mmap
27 */
28static struct page* ncp_file_mmap_nopage(struct vm_area_struct *area,
29 unsigned long address, int *type)
30{
31 struct file *file = area->vm_file;
32 struct dentry *dentry = file->f_dentry;
33 struct inode *inode = dentry->d_inode;
34 struct page* page;
35 char *pg_addr;
36 unsigned int already_read;
37 unsigned int count;
38 int bufsize;
39 int pos;
40
41 page = alloc_page(GFP_HIGHUSER); /* ncpfs has nothing against high pages
42 as long as recvmsg and memset works on it */
43 if (!page)
44 return page;
45 pg_addr = kmap(page);
46 address &= PAGE_MASK;
47 pos = address - area->vm_start + (area->vm_pgoff << PAGE_SHIFT);
48
49 count = PAGE_SIZE;
50 if (address + PAGE_SIZE > area->vm_end) {
51 count = area->vm_end - address;
52 }
53 /* what we can read in one go */
54 bufsize = NCP_SERVER(inode)->buffer_size;
55
56 already_read = 0;
57 if (ncp_make_open(inode, O_RDONLY) >= 0) {
58 while (already_read < count) {
59 int read_this_time;
60 int to_read;
61
62 to_read = bufsize - (pos % bufsize);
63
64 to_read = min_t(unsigned int, to_read, count - already_read);
65
66 if (ncp_read_kernel(NCP_SERVER(inode),
67 NCP_FINFO(inode)->file_handle,
68 pos, to_read,
69 pg_addr + already_read,
70 &read_this_time) != 0) {
71 read_this_time = 0;
72 }
73 pos += read_this_time;
74 already_read += read_this_time;
75
76 if (read_this_time < to_read) {
77 break;
78 }
79 }
80 ncp_inode_close(inode);
81
82 }
83
84 if (already_read < PAGE_SIZE)
85 memset(pg_addr + already_read, 0, PAGE_SIZE - already_read);
86 flush_dcache_page(page);
87 kunmap(page);
88
89 /*
90 * If I understand ncp_read_kernel() properly, the above always
91 * fetches from the network, here the analogue of disk.
92 * -- wli
93 */
94 if (type)
95 *type = VM_FAULT_MAJOR;
96 inc_page_state(pgmajfault);
97 return page;
98}
99
100static struct vm_operations_struct ncp_file_mmap =
101{
102 .nopage = ncp_file_mmap_nopage,
103};
104
105
106/* This is used for a general mmap of a ncp file */
107int ncp_mmap(struct file *file, struct vm_area_struct *vma)
108{
109 struct inode *inode = file->f_dentry->d_inode;
110
111 DPRINTK("ncp_mmap: called\n");
112
113 if (!ncp_conn_valid(NCP_SERVER(inode)))
114 return -EIO;
115
116 /* only PAGE_COW or read-only supported now */
117 if (vma->vm_flags & VM_SHARED)
118 return -EINVAL;
119 /* we do not support files bigger than 4GB... We eventually
120 supports just 4GB... */
121 if (((vma->vm_end - vma->vm_start) >> PAGE_SHIFT) + vma->vm_pgoff
122 > (1U << (32 - PAGE_SHIFT)))
123 return -EFBIG;
124
125 vma->vm_ops = &ncp_file_mmap;
126 file_accessed(file);
127 return 0;
128}