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linux-sg2042/fs/coda/psdev.c

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