d0217ac04c
Change ->fault prototype. We now return an int, which contains VM_FAULT_xxx code in the low byte, and FAULT_RET_xxx code in the next byte. FAULT_RET_ code tells the VM whether a page was found, whether it has been locked, and potentially other things. This is not quite the way he wanted it yet, but that's changed in the next patch (which requires changes to arch code). This means we no longer set VM_CAN_INVALIDATE in the vma in order to say that a page is locked which requires filemap_nopage to go away (because we can no longer remain backward compatible without that flag), but we were going to do that anyway. struct fault_data is renamed to struct vm_fault as Linus asked. address is now a void __user * that we should firmly encourage drivers not to use without really good reason. The page is now returned via a page pointer in the vm_fault struct. Signed-off-by: Nick Piggin <npiggin@suse.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
130 lines
3 KiB
C
130 lines
3 KiB
C
/*
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* mmap.c
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*
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* Copyright (C) 1995, 1996 by Volker Lendecke
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* Modified 1997 Peter Waltenberg, Bill Hawes, David Woodhouse for 2.1 dcache
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*
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*/
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#include <linux/stat.h>
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#include <linux/time.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/slab.h>
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#include <linux/fcntl.h>
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#include <linux/ncp_fs.h>
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#include "ncplib_kernel.h"
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#include <asm/uaccess.h>
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#include <asm/system.h>
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/*
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* Fill in the supplied page for mmap
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* XXX: how are we excluding truncate/invalidate here? Maybe need to lock
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* page?
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*/
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static int ncp_file_mmap_fault(struct vm_area_struct *area,
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struct vm_fault *vmf)
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{
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struct file *file = area->vm_file;
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struct dentry *dentry = file->f_path.dentry;
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struct inode *inode = dentry->d_inode;
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char *pg_addr;
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unsigned int already_read;
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unsigned int count;
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int bufsize;
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int pos; /* XXX: loff_t ? */
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/*
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* ncpfs has nothing against high pages as long
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* as recvmsg and memset works on it
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*/
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vmf->page = alloc_page(GFP_HIGHUSER);
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if (!vmf->page)
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return VM_FAULT_OOM;
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pg_addr = kmap(vmf->page);
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pos = vmf->pgoff << PAGE_SHIFT;
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count = PAGE_SIZE;
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if ((unsigned long)vmf->virtual_address + PAGE_SIZE > area->vm_end) {
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WARN_ON(1); /* shouldn't happen? */
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count = area->vm_end - (unsigned long)vmf->virtual_address;
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}
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/* what we can read in one go */
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bufsize = NCP_SERVER(inode)->buffer_size;
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already_read = 0;
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if (ncp_make_open(inode, O_RDONLY) >= 0) {
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while (already_read < count) {
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int read_this_time;
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int to_read;
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to_read = bufsize - (pos % bufsize);
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to_read = min_t(unsigned int, to_read, count - already_read);
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if (ncp_read_kernel(NCP_SERVER(inode),
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NCP_FINFO(inode)->file_handle,
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pos, to_read,
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pg_addr + already_read,
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&read_this_time) != 0) {
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read_this_time = 0;
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}
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pos += read_this_time;
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already_read += read_this_time;
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if (read_this_time < to_read) {
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break;
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}
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}
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ncp_inode_close(inode);
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}
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if (already_read < PAGE_SIZE)
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memset(pg_addr + already_read, 0, PAGE_SIZE - already_read);
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flush_dcache_page(vmf->page);
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kunmap(vmf->page);
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/*
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* If I understand ncp_read_kernel() properly, the above always
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* fetches from the network, here the analogue of disk.
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* -- wli
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*/
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count_vm_event(PGMAJFAULT);
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return VM_FAULT_MAJOR;
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}
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static struct vm_operations_struct ncp_file_mmap =
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{
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.fault = ncp_file_mmap_fault,
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};
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/* This is used for a general mmap of a ncp file */
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int ncp_mmap(struct file *file, struct vm_area_struct *vma)
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{
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struct inode *inode = file->f_path.dentry->d_inode;
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DPRINTK("ncp_mmap: called\n");
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if (!ncp_conn_valid(NCP_SERVER(inode)))
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return -EIO;
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/* only PAGE_COW or read-only supported now */
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if (vma->vm_flags & VM_SHARED)
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return -EINVAL;
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/* we do not support files bigger than 4GB... We eventually
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supports just 4GB... */
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if (((vma->vm_end - vma->vm_start) >> PAGE_SHIFT) + vma->vm_pgoff
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> (1U << (32 - PAGE_SHIFT)))
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return -EFBIG;
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vma->vm_ops = &ncp_file_mmap;
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file_accessed(file);
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return 0;
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}
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