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 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
 97static 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 */
104int 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}