fs/9p/vfs_addr.c

   1 /*
   2  *  linux/fs/9p/vfs_addr.c
   3  *
   4  * This file contians vfs address (mmap) ops for 9P2000.
   5  *
   6  *  Copyright (C) 2005 by Eric Van Hensbergen <ericvh@gmail.com>
   7  *  Copyright (C) 2002 by Ron Minnich <rminnich@lanl.gov>
   8  *
   9  *  This program is free software; you can redistribute it and/or modify
  10  *  it under the terms of the GNU General Public License version 2
  11  *  as published by the Free Software Foundation.
  12  *
  13  *  This program is distributed in the hope that it will be useful,
  14  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  15  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16  *  GNU General Public License for more details.
  17  *
  18  *  You should have received a copy of the GNU General Public License
  19  *  along with this program; if not, write to:
  20  *  Free Software Foundation
  21  *  51 Franklin Street, Fifth Floor
  22  *  Boston, MA  02111-1301  USA
  23  *
  24  */
  25
  26 #include <linux/module.h>
  27 #include <linux/errno.h>
  28 #include <linux/fs.h>
  29 #include <linux/file.h>
  30 #include <linux/stat.h>
  31 #include <linux/string.h>
  32 #include <linux/inet.h>
  33 #include <linux/pagemap.h>
  34 #include <linux/idr.h>
  35 #include <linux/sched.h>
  36 #include <net/9p/9p.h>
  37 #include <net/9p/client.h>
  38
  39 #include "v9fs.h"
  40 #include "v9fs_vfs.h"
  41
  42 /**
  43  * v9fs_vfs_readpage - read an entire page in from 9P
  44  *
  45  * @filp: file being read
  46  * @page: structure to page
  47  *
  48  */
  49
  50 static int v9fs_vfs_readpage(struct file *filp, struct page *page)
  51 {
  52         int retval;
  53         loff_t offset;
  54         char *buffer;
  55
  56         P9_DPRINTK(P9_DEBUG_VFS, "\n");
  57         buffer = kmap(page);
  58         offset = page_offset(page);
  59
  60         retval = v9fs_file_readn(filp, buffer, NULL, offset, PAGE_CACHE_SIZE);
  61         if (retval < 0)
  62                 goto done;
  63
  64         memset(buffer + retval, 0, PAGE_CACHE_SIZE - retval);
  65         flush_dcache_page(page);
  66         SetPageUptodate(page);
  67         retval = 0;
  68
  69 done:
  70         kunmap(page);
  71         unlock_page(page);
  72         return retval;
  73 }
  74
  75 const struct address_space_operations v9fs_addr_operations = {
  76       .readpage = v9fs_vfs_readpage,
  77 };