463 строки
11 KiB
C
463 строки
11 KiB
C
/*
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* An implementation of a loadable kernel mode driver providing
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* multiple kernel/user space bidirectional communications links.
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*
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* Author: Alan Cox <alan@redhat.com>
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version
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* 2 of the License, or (at your option) any later version.
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*
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* Adapted to become the Linux 2.0 Coda pseudo device
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* Peter Braam <braam@maths.ox.ac.uk>
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* Michael Callahan <mjc@emmy.smith.edu>
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*
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* Changes for Linux 2.1
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* Copyright (c) 1997 Carnegie-Mellon University
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*/
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#include <linux/module.h>
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#include <linux/errno.h>
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#include <linux/kernel.h>
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#include <linux/major.h>
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#include <linux/time.h>
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#include <linux/slab.h>
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#include <linux/ioport.h>
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#include <linux/fcntl.h>
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#include <linux/delay.h>
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#include <linux/skbuff.h>
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#include <linux/proc_fs.h>
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#include <linux/devfs_fs_kernel.h>
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#include <linux/vmalloc.h>
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#include <linux/fs.h>
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#include <linux/file.h>
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#include <linux/poll.h>
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#include <linux/init.h>
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#include <linux/list.h>
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#include <linux/smp_lock.h>
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#include <linux/device.h>
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#include <asm/io.h>
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#include <asm/system.h>
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#include <asm/poll.h>
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#include <asm/uaccess.h>
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#include <linux/coda.h>
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#include <linux/coda_linux.h>
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#include <linux/coda_fs_i.h>
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#include <linux/coda_psdev.h>
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#include <linux/coda_proc.h>
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#define upc_free(r) kfree(r)
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/*
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* Coda stuff
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*/
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extern struct file_system_type coda_fs_type;
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/* statistics */
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int coda_hard; /* allows signals during upcalls */
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unsigned long coda_timeout = 30; /* .. secs, then signals will dequeue */
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struct venus_comm coda_comms[MAX_CODADEVS];
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static struct class *coda_psdev_class;
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/*
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* Device operations
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*/
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static unsigned int coda_psdev_poll(struct file *file, poll_table * wait)
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{
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struct venus_comm *vcp = (struct venus_comm *) file->private_data;
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unsigned int mask = POLLOUT | POLLWRNORM;
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poll_wait(file, &vcp->vc_waitq, wait);
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if (!list_empty(&vcp->vc_pending))
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mask |= POLLIN | POLLRDNORM;
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return mask;
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}
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static int coda_psdev_ioctl(struct inode * inode, struct file * filp,
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unsigned int cmd, unsigned long arg)
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{
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unsigned int data;
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switch(cmd) {
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case CIOC_KERNEL_VERSION:
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data = CODA_KERNEL_VERSION;
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return put_user(data, (int __user *) arg);
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default:
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return -ENOTTY;
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}
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return 0;
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}
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/*
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* Receive a message written by Venus to the psdev
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*/
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static ssize_t coda_psdev_write(struct file *file, const char __user *buf,
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size_t nbytes, loff_t *off)
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{
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struct venus_comm *vcp = (struct venus_comm *) file->private_data;
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struct upc_req *req = NULL;
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struct upc_req *tmp;
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struct list_head *lh;
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struct coda_in_hdr hdr;
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ssize_t retval = 0, count = 0;
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int error;
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/* Peek at the opcode, uniquefier */
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if (copy_from_user(&hdr, buf, 2 * sizeof(u_long)))
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return -EFAULT;
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if (DOWNCALL(hdr.opcode)) {
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struct super_block *sb = NULL;
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union outputArgs *dcbuf;
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int size = sizeof(*dcbuf);
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sb = vcp->vc_sb;
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if ( !sb ) {
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count = nbytes;
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goto out;
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}
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if ( nbytes < sizeof(struct coda_out_hdr) ) {
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printk("coda_downcall opc %d uniq %d, not enough!\n",
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hdr.opcode, hdr.unique);
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count = nbytes;
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goto out;
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}
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if ( nbytes > size ) {
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printk("Coda: downcall opc %d, uniq %d, too much!",
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hdr.opcode, hdr.unique);
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nbytes = size;
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}
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CODA_ALLOC(dcbuf, union outputArgs *, nbytes);
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if (copy_from_user(dcbuf, buf, nbytes)) {
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CODA_FREE(dcbuf, nbytes);
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retval = -EFAULT;
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goto out;
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}
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/* what downcall errors does Venus handle ? */
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lock_kernel();
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error = coda_downcall(hdr.opcode, dcbuf, sb);
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unlock_kernel();
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CODA_FREE(dcbuf, nbytes);
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if (error) {
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printk("psdev_write: coda_downcall error: %d\n", error);
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retval = error;
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goto out;
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}
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count = nbytes;
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goto out;
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}
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/* Look for the message on the processing queue. */
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lock_kernel();
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list_for_each(lh, &vcp->vc_processing) {
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tmp = list_entry(lh, struct upc_req , uc_chain);
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if (tmp->uc_unique == hdr.unique) {
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req = tmp;
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list_del(&req->uc_chain);
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break;
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}
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}
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unlock_kernel();
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if (!req) {
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printk("psdev_write: msg (%d, %d) not found\n",
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hdr.opcode, hdr.unique);
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retval = -ESRCH;
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goto out;
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}
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/* move data into response buffer. */
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if (req->uc_outSize < nbytes) {
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printk("psdev_write: too much cnt: %d, cnt: %ld, opc: %d, uniq: %d.\n",
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req->uc_outSize, (long)nbytes, hdr.opcode, hdr.unique);
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nbytes = req->uc_outSize; /* don't have more space! */
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}
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if (copy_from_user(req->uc_data, buf, nbytes)) {
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req->uc_flags |= REQ_ABORT;
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wake_up(&req->uc_sleep);
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retval = -EFAULT;
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goto out;
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}
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/* adjust outsize. is this useful ?? */
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req->uc_outSize = nbytes;
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req->uc_flags |= REQ_WRITE;
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count = nbytes;
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/* Convert filedescriptor into a file handle */
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if (req->uc_opcode == CODA_OPEN_BY_FD) {
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struct coda_open_by_fd_out *outp =
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(struct coda_open_by_fd_out *)req->uc_data;
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outp->fh = fget(outp->fd);
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}
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wake_up(&req->uc_sleep);
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out:
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return(count ? count : retval);
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}
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/*
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* Read a message from the kernel to Venus
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*/
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static ssize_t coda_psdev_read(struct file * file, char __user * buf,
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size_t nbytes, loff_t *off)
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{
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DECLARE_WAITQUEUE(wait, current);
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struct venus_comm *vcp = (struct venus_comm *) file->private_data;
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struct upc_req *req;
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ssize_t retval = 0, count = 0;
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if (nbytes == 0)
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return 0;
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lock_kernel();
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add_wait_queue(&vcp->vc_waitq, &wait);
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set_current_state(TASK_INTERRUPTIBLE);
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while (list_empty(&vcp->vc_pending)) {
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if (file->f_flags & O_NONBLOCK) {
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retval = -EAGAIN;
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break;
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}
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if (signal_pending(current)) {
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retval = -ERESTARTSYS;
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break;
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}
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schedule();
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}
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set_current_state(TASK_RUNNING);
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remove_wait_queue(&vcp->vc_waitq, &wait);
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if (retval)
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goto out;
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req = list_entry(vcp->vc_pending.next, struct upc_req,uc_chain);
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list_del(&req->uc_chain);
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/* Move the input args into userspace */
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count = req->uc_inSize;
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if (nbytes < req->uc_inSize) {
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printk ("psdev_read: Venus read %ld bytes of %d in message\n",
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(long)nbytes, req->uc_inSize);
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count = nbytes;
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}
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if (copy_to_user(buf, req->uc_data, count))
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retval = -EFAULT;
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/* If request was not a signal, enqueue and don't free */
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if (!(req->uc_flags & REQ_ASYNC)) {
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req->uc_flags |= REQ_READ;
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list_add(&(req->uc_chain), vcp->vc_processing.prev);
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goto out;
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}
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CODA_FREE(req->uc_data, sizeof(struct coda_in_hdr));
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upc_free(req);
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out:
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unlock_kernel();
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return (count ? count : retval);
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}
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static int coda_psdev_open(struct inode * inode, struct file * file)
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{
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struct venus_comm *vcp;
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int idx;
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lock_kernel();
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idx = iminor(inode);
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if(idx >= MAX_CODADEVS) {
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unlock_kernel();
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return -ENODEV;
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}
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vcp = &coda_comms[idx];
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if(vcp->vc_inuse) {
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unlock_kernel();
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return -EBUSY;
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}
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if (!vcp->vc_inuse++) {
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INIT_LIST_HEAD(&vcp->vc_pending);
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INIT_LIST_HEAD(&vcp->vc_processing);
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init_waitqueue_head(&vcp->vc_waitq);
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vcp->vc_sb = NULL;
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vcp->vc_seq = 0;
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}
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file->private_data = vcp;
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unlock_kernel();
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return 0;
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}
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static int coda_psdev_release(struct inode * inode, struct file * file)
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{
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struct venus_comm *vcp = (struct venus_comm *) file->private_data;
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struct upc_req *req, *tmp;
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lock_kernel();
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if ( !vcp->vc_inuse ) {
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unlock_kernel();
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printk("psdev_release: Not open.\n");
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return -1;
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}
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if (--vcp->vc_inuse) {
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unlock_kernel();
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return 0;
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}
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/* Wakeup clients so they can return. */
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list_for_each_entry_safe(req, tmp, &vcp->vc_pending, uc_chain) {
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/* Async requests need to be freed here */
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if (req->uc_flags & REQ_ASYNC) {
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CODA_FREE(req->uc_data, sizeof(struct coda_in_hdr));
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upc_free(req);
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continue;
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}
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req->uc_flags |= REQ_ABORT;
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wake_up(&req->uc_sleep);
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}
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list_for_each_entry(req, &vcp->vc_processing, uc_chain) {
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req->uc_flags |= REQ_ABORT;
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wake_up(&req->uc_sleep);
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}
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unlock_kernel();
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return 0;
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}
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static struct file_operations coda_psdev_fops = {
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.owner = THIS_MODULE,
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.read = coda_psdev_read,
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.write = coda_psdev_write,
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.poll = coda_psdev_poll,
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.ioctl = coda_psdev_ioctl,
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.open = coda_psdev_open,
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.release = coda_psdev_release,
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};
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static int init_coda_psdev(void)
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{
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int i, err = 0;
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if (register_chrdev(CODA_PSDEV_MAJOR, "coda", &coda_psdev_fops)) {
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printk(KERN_ERR "coda_psdev: unable to get major %d\n",
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CODA_PSDEV_MAJOR);
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return -EIO;
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}
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coda_psdev_class = class_create(THIS_MODULE, "coda");
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if (IS_ERR(coda_psdev_class)) {
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err = PTR_ERR(coda_psdev_class);
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goto out_chrdev;
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}
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devfs_mk_dir ("coda");
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for (i = 0; i < MAX_CODADEVS; i++) {
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class_device_create(coda_psdev_class, MKDEV(CODA_PSDEV_MAJOR,i),
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NULL, "cfs%d", i);
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err = devfs_mk_cdev(MKDEV(CODA_PSDEV_MAJOR, i),
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S_IFCHR|S_IRUSR|S_IWUSR, "coda/%d", i);
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if (err)
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goto out_class;
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}
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coda_sysctl_init();
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goto out;
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out_class:
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for (i = 0; i < MAX_CODADEVS; i++)
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class_device_destroy(coda_psdev_class, MKDEV(CODA_PSDEV_MAJOR, i));
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class_destroy(coda_psdev_class);
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out_chrdev:
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unregister_chrdev(CODA_PSDEV_MAJOR, "coda");
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out:
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return err;
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}
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MODULE_AUTHOR("Peter J. Braam <braam@cs.cmu.edu>");
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MODULE_LICENSE("GPL");
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extern int coda_init_inodecache(void);
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extern void coda_destroy_inodecache(void);
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static int __init init_coda(void)
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{
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int status;
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int i;
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printk(KERN_INFO "Coda Kernel/Venus communications, "
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#ifdef CONFIG_CODA_FS_OLD_API
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"v5.3.20"
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#else
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"v6.0.0"
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#endif
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", coda@cs.cmu.edu\n");
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status = coda_init_inodecache();
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if (status)
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goto out2;
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status = init_coda_psdev();
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if ( status ) {
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printk("Problem (%d) in init_coda_psdev\n", status);
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goto out1;
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}
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status = register_filesystem(&coda_fs_type);
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if (status) {
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printk("coda: failed to register filesystem!\n");
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goto out;
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}
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return 0;
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out:
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for (i = 0; i < MAX_CODADEVS; i++) {
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class_device_destroy(coda_psdev_class, MKDEV(CODA_PSDEV_MAJOR, i));
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devfs_remove("coda/%d", i);
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}
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class_destroy(coda_psdev_class);
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devfs_remove("coda");
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unregister_chrdev(CODA_PSDEV_MAJOR, "coda");
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coda_sysctl_clean();
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out1:
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coda_destroy_inodecache();
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out2:
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return status;
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}
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static void __exit exit_coda(void)
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{
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int err, i;
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err = unregister_filesystem(&coda_fs_type);
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if ( err != 0 ) {
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printk("coda: failed to unregister filesystem\n");
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}
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for (i = 0; i < MAX_CODADEVS; i++) {
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class_device_destroy(coda_psdev_class, MKDEV(CODA_PSDEV_MAJOR, i));
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devfs_remove("coda/%d", i);
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}
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class_destroy(coda_psdev_class);
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devfs_remove("coda");
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unregister_chrdev(CODA_PSDEV_MAJOR, "coda");
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coda_sysctl_clean();
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coda_destroy_inodecache();
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}
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module_init(init_coda);
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module_exit(exit_coda);
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