tjh.dev
Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
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 file *file = area->vm_file;
34 struct dentry *dentry = file->f_path.dentry;
35 struct inode *inode = dentry->d_inode;
36 char *pg_addr;
37 unsigned int already_read;
38 unsigned int count;
39 int bufsize;
40 int pos; /* XXX: loff_t ? */
41
42 /*
43 * ncpfs has nothing against high pages as long
44 * as recvmsg and memset works on it
45 */
46 vmf->page = alloc_page(GFP_HIGHUSER);
47 if (!vmf->page)
48 return VM_FAULT_OOM;
49 pg_addr = kmap(vmf->page);
50 pos = vmf->pgoff << PAGE_SHIFT;
51
52 count = PAGE_SIZE;
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(vmf->page);
87 kunmap(vmf->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 * -- nyc
93 */
94 count_vm_event(PGMAJFAULT);
95 mem_cgroup_count_vm_event(area->vm_mm, PGMAJFAULT);
96 return VM_FAULT_MAJOR;
97}
98
99static const struct vm_operations_struct ncp_file_mmap =
100{
101 .fault = ncp_file_mmap_fault,
102};
103
104
105/* This is used for a general mmap of a ncp file */
106int ncp_mmap(struct file *file, struct vm_area_struct *vma)
107{
108 struct inode *inode = file_inode(file);
109
110 DPRINTK("ncp_mmap: called\n");
111
112 if (!ncp_conn_valid(NCP_SERVER(inode)))
113 return -EIO;
114
115 /* only PAGE_COW or read-only supported now */
116 if (vma->vm_flags & VM_SHARED)
117 return -EINVAL;
118 /* we do not support files bigger than 4GB... We eventually
119 supports just 4GB... */
120 if (vma_pages(vma) + vma->vm_pgoff
121 > (1U << (32 - PAGE_SHIFT)))
122 return -EFBIG;
123
124 vma->vm_ops = &ncp_file_mmap;
125 file_accessed(file);
126 return 0;
127}