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	 * -- wli
 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->f_path.dentry->d_inode;
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}