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 */
ncp_file_mmap_fault(struct vm_area_struct * area,struct vm_fault * vmf)30 static 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
97 static 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 */
ncp_mmap(struct file * file,struct vm_area_struct * vma)104 int 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