1/*
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/gfp.h>
13#include <linux/mm.h>
14#include <linux/shm.h>
15#include <linux/errno.h>
16#include <linux/mman.h>
17#include <linux/string.h>
18#include <linux/fcntl.h>
19#include <linux/memcontrol.h>
20
21#include <asm/uaccess.h>
22
23#include "ncp_fs.h"
24
25/*
26 * Fill in the supplied page for mmap
27 * XXX: how are we excluding truncate/invalidate here? Maybe need to lock
28 * page?
29 */
30static int ncp_file_mmap_fault(struct vm_area_struct *area,
31					struct vm_fault *vmf)
32{
33	struct inode *inode = file_inode(area->vm_file);
34	char *pg_addr;
35	unsigned int already_read;
36	unsigned int count;
37	int bufsize;
38	int pos; /* XXX: loff_t ? */
39
40	/*
41	 * ncpfs has nothing against high pages as long
42	 * as recvmsg and memset works on it
43	 */
44	vmf->page = alloc_page(GFP_HIGHUSER);
45	if (!vmf->page)
46		return VM_FAULT_OOM;
47	pg_addr = kmap(vmf->page);
48	pos = vmf->pgoff << PAGE_SHIFT;
49
50	count = PAGE_SIZE;
51	/* what we can read in one go */
52	bufsize = NCP_SERVER(inode)->buffer_size;
53
54	already_read = 0;
55	if (ncp_make_open(inode, O_RDONLY) >= 0) {
56		while (already_read < count) {
57			int read_this_time;
58			int to_read;
59
60			to_read = bufsize - (pos % bufsize);
61
62			to_read = min_t(unsigned int, to_read, count - already_read);
63
64			if (ncp_read_kernel(NCP_SERVER(inode),
65				     NCP_FINFO(inode)->file_handle,
66				     pos, to_read,
67				     pg_addr + already_read,
68				     &read_this_time) != 0) {
69				read_this_time = 0;
70			}
71			pos += read_this_time;
72			already_read += read_this_time;
73
74			if (read_this_time < to_read) {
75				break;
76			}
77		}
78		ncp_inode_close(inode);
79
80	}
81
82	if (already_read < PAGE_SIZE)
83		memset(pg_addr + already_read, 0, PAGE_SIZE - already_read);
84	flush_dcache_page(vmf->page);
85	kunmap(vmf->page);
86
87	/*
88	 * If I understand ncp_read_kernel() properly, the above always
89	 * fetches from the network, here the analogue of disk.
90	 * -- nyc
91	 */
92	count_vm_event(PGMAJFAULT);
93	mem_cgroup_count_vm_event(area->vm_mm, PGMAJFAULT);
94	return VM_FAULT_MAJOR;
95}
96
97static const struct vm_operations_struct ncp_file_mmap =
98{
99	.fault = ncp_file_mmap_fault,
100};
101
102
103/* This is used for a general mmap of a ncp file */
104int ncp_mmap(struct file *file, struct vm_area_struct *vma)
105{
106	struct inode *inode = file_inode(file);
107
108	ncp_dbg(1, "called\n");
109
110	if (!ncp_conn_valid(NCP_SERVER(inode)))
111		return -EIO;
112
113	/* only PAGE_COW or read-only supported now */
114	if (vma->vm_flags & VM_SHARED)
115		return -EINVAL;
116	/* we do not support files bigger than 4GB... We eventually
117	   supports just 4GB... */
118	if (vma_pages(vma) + vma->vm_pgoff
119	   > (1U << (32 - PAGE_SHIFT)))
120		return -EFBIG;
121
122	vma->vm_ops = &ncp_file_mmap;
123	file_accessed(file);
124	return 0;
125}
126