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 #include <asm/system.h>
23
24 #include "ncp_fs.h"
25
26 /*
27 * Fill in the supplied page for mmap
28 * XXX: how are we excluding truncate/invalidate here? Maybe need to lock
29 * page?
30 */
ncp_file_mmap_fault(struct vm_area_struct * area,struct vm_fault * vmf)31 static int ncp_file_mmap_fault(struct vm_area_struct *area,
32 struct vm_fault *vmf)
33 {
34 struct file *file = area->vm_file;
35 struct dentry *dentry = file->f_path.dentry;
36 struct inode *inode = dentry->d_inode;
37 char *pg_addr;
38 unsigned int already_read;
39 unsigned int count;
40 int bufsize;
41 int pos; /* XXX: loff_t ? */
42
43 /*
44 * ncpfs has nothing against high pages as long
45 * as recvmsg and memset works on it
46 */
47 vmf->page = alloc_page(GFP_HIGHUSER);
48 if (!vmf->page)
49 return VM_FAULT_OOM;
50 pg_addr = kmap(vmf->page);
51 pos = vmf->pgoff << PAGE_SHIFT;
52
53 count = PAGE_SIZE;
54 /* what we can read in one go */
55 bufsize = NCP_SERVER(inode)->buffer_size;
56
57 already_read = 0;
58 if (ncp_make_open(inode, O_RDONLY) >= 0) {
59 while (already_read < count) {
60 int read_this_time;
61 int to_read;
62
63 to_read = bufsize - (pos % bufsize);
64
65 to_read = min_t(unsigned int, to_read, count - already_read);
66
67 if (ncp_read_kernel(NCP_SERVER(inode),
68 NCP_FINFO(inode)->file_handle,
69 pos, to_read,
70 pg_addr + already_read,
71 &read_this_time) != 0) {
72 read_this_time = 0;
73 }
74 pos += read_this_time;
75 already_read += read_this_time;
76
77 if (read_this_time < to_read) {
78 break;
79 }
80 }
81 ncp_inode_close(inode);
82
83 }
84
85 if (already_read < PAGE_SIZE)
86 memset(pg_addr + already_read, 0, PAGE_SIZE - already_read);
87 flush_dcache_page(vmf->page);
88 kunmap(vmf->page);
89
90 /*
91 * If I understand ncp_read_kernel() properly, the above always
92 * fetches from the network, here the analogue of disk.
93 * -- wli
94 */
95 count_vm_event(PGMAJFAULT);
96 mem_cgroup_count_vm_event(area->vm_mm, PGMAJFAULT);
97 return VM_FAULT_MAJOR;
98 }
99
100 static const struct vm_operations_struct ncp_file_mmap =
101 {
102 .fault = ncp_file_mmap_fault,
103 };
104
105
106 /* This is used for a general mmap of a ncp file */
ncp_mmap(struct file * file,struct vm_area_struct * vma)107 int ncp_mmap(struct file *file, struct vm_area_struct *vma)
108 {
109 struct inode *inode = file->f_path.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 }
129