156 lines
3.7 KiB
C
156 lines
3.7 KiB
C
/*
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* fs/nfs/mmap.c by Jon Tombs 15 Aug 1993
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*
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* This code is from
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* linux/mm/mmap.c which was written by obz, Linus and Eric
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* and
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* linux/mm/memory.c by Linus Torvalds and others
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*
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* Copyright (C) 1993
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*
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*/
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#include <linux/stat.h>
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#include <linux/sched.h>
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#include <linux/kernel.h>
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#include <linux/mm.h>
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#include <linux/shm.h>
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#include <linux/errno.h>
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#include <linux/mman.h>
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#include <linux/string.h>
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#include <linux/malloc.h>
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#include <linux/nfs_fs.h>
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#include <asm/segment.h>
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#include <asm/system.h>
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extern int share_page(struct vm_area_struct * area, struct task_struct * tsk,
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struct inode * inode, unsigned long address, unsigned long error_code,
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unsigned long newpage);
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extern unsigned long put_page(struct task_struct * tsk,unsigned long page,
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unsigned long address,int prot);
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static void nfs_file_mmap_nopage(int error_code, struct vm_area_struct * area,
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unsigned long address);
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extern void file_mmap_free(struct vm_area_struct * area);
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extern int file_mmap_share(struct vm_area_struct * from, struct vm_area_struct * to,
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unsigned long address);
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struct vm_operations_struct nfs_file_mmap = {
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NULL, /* open */
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file_mmap_free, /* close */
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nfs_file_mmap_nopage, /* nopage */
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NULL, /* wppage */
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file_mmap_share, /* share */
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NULL, /* unmap */
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};
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/* This is used for a general mmap of a nfs file */
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int nfs_mmap(struct inode * inode, struct file * file,
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unsigned long addr, size_t len, int prot, unsigned long off)
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{
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struct vm_area_struct * mpnt;
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if (prot & PAGE_RW) /* only PAGE_COW or read-only supported now */
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return -EINVAL;
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if (off & (inode->i_sb->s_blocksize - 1))
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return -EINVAL;
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if (!inode->i_sb || !S_ISREG(inode->i_mode))
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return -EACCES;
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if (!IS_RDONLY(inode)) {
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inode->i_atime = CURRENT_TIME;
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inode->i_dirt = 1;
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}
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mpnt = (struct vm_area_struct * ) kmalloc(sizeof(struct vm_area_struct), GFP_KERNEL);
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if (!mpnt)
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return -ENOMEM;
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unmap_page_range(addr, len);
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mpnt->vm_task = current;
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mpnt->vm_start = addr;
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mpnt->vm_end = addr + len;
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mpnt->vm_page_prot = prot;
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mpnt->vm_share = NULL;
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mpnt->vm_inode = inode;
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inode->i_count++;
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mpnt->vm_offset = off;
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mpnt->vm_ops = &nfs_file_mmap;
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insert_vm_struct(current, mpnt);
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merge_segments(current->mmap, NULL, NULL);
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return 0;
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}
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static void nfs_file_mmap_nopage(int error_code, struct vm_area_struct * area,
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unsigned long address)
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{
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struct inode * inode = area->vm_inode;
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unsigned int clear;
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unsigned long page;
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unsigned long tmp;
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int n;
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int i;
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int pos;
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struct nfs_fattr fattr;
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address &= PAGE_MASK;
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pos = address - area->vm_start + area->vm_offset;
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page = get_free_page(GFP_KERNEL);
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if (share_page(area, area->vm_task, inode, address, error_code, page)) {
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++area->vm_task->min_flt;
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return;
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}
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++area->vm_task->maj_flt;
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if (!page) {
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oom(current);
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put_page(area->vm_task, BAD_PAGE, address, PAGE_PRIVATE);
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return;
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}
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clear = 0;
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if (address + PAGE_SIZE > area->vm_end) {
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clear = address + PAGE_SIZE - area->vm_end;
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}
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n = NFS_SERVER(inode)->rsize; /* what we can read in one go */
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for (i = 0; i < (PAGE_SIZE - clear); i += n) {
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int hunk, result;
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hunk = PAGE_SIZE - i;
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if (hunk > n)
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hunk = n;
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result = nfs_proc_read(NFS_SERVER(inode), NFS_FH(inode),
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pos, hunk, (char *) (page + i), &fattr);
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if (result < 0)
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break;
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pos += result;
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if (result < n) {
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i += result;
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break;
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}
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}
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#ifdef doweneedthishere
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nfs_refresh_inode(inode, &fattr);
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#endif
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if (!(error_code & PAGE_RW)) {
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if (share_page(area, area->vm_task, inode, address, error_code, page))
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return;
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}
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tmp = page + PAGE_SIZE;
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while (clear--) {
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*(char *)--tmp = 0;
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}
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if (put_page(area->vm_task,page,address,area->vm_page_prot))
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return;
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free_page(page);
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oom(current);
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}
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