fs/nfs/mmap.c

/* */
This source file includes following definitions.
nfs_mmap
nfs_file_mmap_nopage
   1 /*
   2  *      fs/nfs/mmap.c   by Jon Tombs 15 Aug 1993
   3  *
   4  * This code is from
   5  *      linux/mm/mmap.c which was written by obz, Linus and Eric
   6  * and
   7  *      linux/mm/memory.c  by Linus Torvalds and others
   8  *
   9  *      Copyright (C) 1993
  10  *
  11  */
  12 #include <linux/stat.h>
  13 #include <linux/sched.h>
  14 #include <linux/kernel.h>
  15 #include <linux/mm.h>
  16 #include <linux/shm.h>
  17 #include <linux/errno.h>
  18 #include <linux/mman.h>
  19 #include <linux/string.h>
  20 #include <linux/malloc.h>
  21 #include <linux/nfs_fs.h>
  22 
  23 #include <asm/segment.h>
  24 #include <asm/system.h>
  25 
  26 static unsigned long nfs_file_mmap_nopage(struct vm_area_struct * area,
  27         unsigned long address, unsigned long page, int error_code);
  28 
  29 extern void file_mmap_free(struct vm_area_struct * area);
  30 extern int file_mmap_share(struct vm_area_struct * from, struct vm_area_struct * to,
  31                                 unsigned long address);
  32 
  33 struct vm_operations_struct nfs_file_mmap = {
  34         NULL,                   /* open */
  35         file_mmap_free,         /* close */
  36         nfs_file_mmap_nopage,   /* nopage */
  37         NULL,                   /* wppage */
  38         file_mmap_share,        /* share */
  39         NULL,                   /* unmap */
  40 };
  41 
  42 
  43 /* This is used for a general mmap of a nfs file */
  44 int nfs_mmap(struct inode * inode, struct file * file,
     /*  */
  45         unsigned long addr, size_t len, int prot, unsigned long off)
  46 {
  47         struct vm_area_struct * mpnt;
  48 
  49         if (prot & PAGE_RW)     /* only PAGE_COW or read-only supported now */
  50                 return -EINVAL;
  51         if (off & (inode->i_sb->s_blocksize - 1))
  52                 return -EINVAL;
  53         if (!inode->i_sb || !S_ISREG(inode->i_mode))
  54                 return -EACCES;
  55         if (!IS_RDONLY(inode)) {
  56                 inode->i_atime = CURRENT_TIME;
  57                 inode->i_dirt = 1;
  58         }
  59 
  60         mpnt = (struct vm_area_struct * ) kmalloc(sizeof(struct vm_area_struct), GFP_KERNEL);
  61         if (!mpnt)
  62                 return -ENOMEM;
  63 
  64         unmap_page_range(addr, len);
  65         mpnt->vm_task = current;
  66         mpnt->vm_start = addr;
  67         mpnt->vm_end = addr + len;
  68         mpnt->vm_page_prot = prot;
  69         mpnt->vm_flags = 0;
  70         mpnt->vm_share = NULL;
  71         mpnt->vm_inode = inode;
  72         inode->i_count++;
  73         mpnt->vm_offset = off;
  74         mpnt->vm_ops = &nfs_file_mmap;
  75         insert_vm_struct(current, mpnt);
  76         merge_segments(current->mm->mmap, NULL, NULL);
  77         return 0;
  78 }
  79 
  80 
  81 static unsigned long nfs_file_mmap_nopage(struct vm_area_struct * area, unsigned long address,
     /*  */
  82         unsigned long page, int error_code)
  83 {
  84         struct inode * inode = area->vm_inode;
  85         unsigned int clear;
  86         unsigned long tmp;
  87         int n;
  88         int i;
  89         int pos;
  90         struct nfs_fattr fattr;
  91 
  92         address &= PAGE_MASK;
  93         pos = address - area->vm_start + area->vm_offset;
  94 
  95         clear = 0;
  96         if (address + PAGE_SIZE > area->vm_end) {
  97                 clear = address + PAGE_SIZE - area->vm_end;
  98         }
  99 
 100         n = NFS_SERVER(inode)->rsize; /* what we can read in one go */
 101 
 102         for (i = 0; i < (PAGE_SIZE - clear); i += n) {
 103                 int hunk, result;
 104 
 105                 hunk = PAGE_SIZE - i;
 106                 if (hunk > n)
 107                         hunk = n;
 108                 result = nfs_proc_read(NFS_SERVER(inode), NFS_FH(inode),
 109                         pos, hunk, (char *) (page + i), &fattr);
 110                 if (result < 0)
 111                         break;
 112                 pos += result;
 113                 if (result < n) {
 114                         i += result;
 115                         break;
 116                 }
 117         }
 118 
 119 #ifdef doweneedthishere
 120         nfs_refresh_inode(inode, &fattr);
 121 #endif
 122 
 123         tmp = page + PAGE_SIZE;
 124         while (clear--) {
 125                 *(char *)--tmp = 0;
 126         }
 127         return page;
 128 }
/* */
root/fs/nfs/mmap.c

DEFINITIONS
