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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 | */ |
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 */ |
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 |
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