Merge remote-tracking branch 'origin/dev/sumit-linux-3.10.96' into TOT-merge
[linux-3.10.git] / fs / ncpfs / mmap.c
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  */
30 static 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
99 static 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 */
106 int 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->vm_end - vma->vm_start) >> PAGE_SHIFT) + 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 }