| Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 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/mm.h> |
| 13 | #include <linux/shm.h> |
| 14 | #include <linux/errno.h> |
| 15 | #include <linux/mman.h> |
| 16 | #include <linux/string.h> |
| 17 | #include <linux/slab.h> |
| 18 | #include <linux/fcntl.h> |
| 19 | #include <linux/ncp_fs.h> |
| 20 | |
| 21 | #include "ncplib_kernel.h" |
| 22 | #include <asm/uaccess.h> |
| 23 | #include <asm/system.h> |
| 24 | |
| 25 | /* |
| 26 | * Fill in the supplied page for mmap |
| 27 | */ |
| 28 | static struct page* ncp_file_mmap_nopage(struct vm_area_struct *area, |
| 29 | unsigned long address, int *type) |
| 30 | { |
| 31 | struct file *file = area->vm_file; |
| 32 | struct dentry *dentry = file->f_dentry; |
| 33 | struct inode *inode = dentry->d_inode; |
| 34 | struct page* page; |
| 35 | char *pg_addr; |
| 36 | unsigned int already_read; |
| 37 | unsigned int count; |
| 38 | int bufsize; |
| 39 | int pos; |
| 40 | |
| 41 | page = alloc_page(GFP_HIGHUSER); /* ncpfs has nothing against high pages |
| 42 | as long as recvmsg and memset works on it */ |
| 43 | if (!page) |
| 44 | return page; |
| 45 | pg_addr = kmap(page); |
| 46 | address &= PAGE_MASK; |
| 47 | pos = address - area->vm_start + (area->vm_pgoff << PAGE_SHIFT); |
| 48 | |
| 49 | count = PAGE_SIZE; |
| 50 | if (address + PAGE_SIZE > area->vm_end) { |
| 51 | count = area->vm_end - address; |
| 52 | } |
| 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(page); |
| 87 | kunmap(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 | * -- wli |
| 93 | */ |
| 94 | if (type) |
| 95 | *type = VM_FAULT_MAJOR; |
| 96 | inc_page_state(pgmajfault); |
| 97 | return page; |
| 98 | } |
| 99 | |
| 100 | static struct vm_operations_struct ncp_file_mmap = |
| 101 | { |
| 102 | .nopage = ncp_file_mmap_nopage, |
| 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_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 | } |