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 <[email protected]>
 *
 *      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  <[email protected]> 
 *              Michael Callahan <[email protected]>           
 *
 *              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/sched.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/vmalloc.h>
#include <linux/fs.h>
#include <linux/file.h>
#include <linux/poll.h>
#include <linux/init.h>
#include <linux/list.h>
#include <linux/mutex.h>
#include <linux/device.h>
#include <asm/io.h>
#include <asm/poll.h>
#include <asm/uaccess.h>

#include <linux/coda.h>
#include <linux/coda_psdev.h>

#include "coda_linux.h"

#include "coda_int.h"

/* 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);
    mutex_lock(&vcp->vc_mutex);
    if (!list_empty(&vcp->vc_pending))
                mask |= POLLIN | POLLRDNORM;
    mutex_unlock(&vcp->vc_mutex);

    return mask;
}

static long coda_psdev_ioctl(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)) {
        union outputArgs *dcbuf;
        int size = sizeof(*dcbuf);

        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 ? */
        error = coda_downcall(vcp, hdr.opcode, dcbuf);

        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. */
    mutex_lock(&vcp->vc_mutex);
    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;
        }
    }
    mutex_unlock(&vcp->vc_mutex);

    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 |= CODA_REQ_ABORT;
        wake_up(&req->uc_sleep);
        retval = -EFAULT;
        goto out;
    }

    /* adjust outsize. is this useful ?? */
    req->uc_outSize = nbytes;
    req->uc_flags |= CODA_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;
        if (!outp->oh.result)
            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;

    mutex_lock(&vcp->vc_mutex);

    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;
        }
        mutex_unlock(&vcp->vc_mutex);
        schedule();
        mutex_lock(&vcp->vc_mutex);
    }

    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 & CODA_REQ_ASYNC)) {
        req->uc_flags |= CODA_REQ_READ;
        list_add_tail(&(req->uc_chain), &vcp->vc_processing);
        goto out;
    }

    CODA_FREE(req->uc_data, sizeof(struct coda_in_hdr));
    kfree(req);
out:
    mutex_unlock(&vcp->vc_mutex);
    return (count ? count : retval);
}

static int coda_psdev_open(struct inode * inode, struct file * file)
{
    struct venus_comm *vcp;
    int idx, err;

    idx = iminor(inode);
    if (idx < 0 || idx >= MAX_CODADEVS)
        return -ENODEV;

    err = -EBUSY;
    vcp = &coda_comms[idx];
    mutex_lock(&vcp->vc_mutex);

    if (!vcp->vc_inuse) {
        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;
        err = 0;
    }

    mutex_unlock(&vcp->vc_mutex);
    return err;
}


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;

    if (!vcp || !vcp->vc_inuse ) {
        printk("psdev_release: Not open.\n");
        return -1;
    }

    mutex_lock(&vcp->vc_mutex);

    /* Wakeup clients so they can return. */
    list_for_each_entry_safe(req, tmp, &vcp->vc_pending, uc_chain) {
        list_del(&req->uc_chain);

        /* Async requests need to be freed here */
        if (req->uc_flags & CODA_REQ_ASYNC) {
            CODA_FREE(req->uc_data, sizeof(struct coda_in_hdr));
            kfree(req);
            continue;
        }
        req->uc_flags |= CODA_REQ_ABORT;
        wake_up(&req->uc_sleep);
    }

    list_for_each_entry_safe(req, tmp, &vcp->vc_processing, uc_chain) {
        list_del(&req->uc_chain);

        req->uc_flags |= CODA_REQ_ABORT;
        wake_up(&req->uc_sleep);
    }

    file->private_data = NULL;
    vcp->vc_inuse--;
    mutex_unlock(&vcp->vc_mutex);
    return 0;
}


static const struct file_operations coda_psdev_fops = {
    .owner      = THIS_MODULE,
    .read       = coda_psdev_read,
    .write      = coda_psdev_write,
    .poll       = coda_psdev_poll,
    .unlocked_ioctl = coda_psdev_ioctl,
    .open       = coda_psdev_open,
    .release    = coda_psdev_release,
    .llseek     = noop_llseek,
};

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;
    }       
    for (i = 0; i < MAX_CODADEVS; i++) {
        mutex_init(&(&coda_comms[i])->vc_mutex);
        device_create(coda_psdev_class, NULL,
                  MKDEV(CODA_PSDEV_MAJOR, i), NULL, "cfs%d", i);
    }
    coda_sysctl_init();
    goto out;

out_chrdev:
    unregister_chrdev(CODA_PSDEV_MAJOR, "coda");
out:
    return err;
}

MODULE_AUTHOR("Jan Harkes, Peter J. Braam");
MODULE_DESCRIPTION("Coda Distributed File System VFS interface");
MODULE_ALIAS_CHARDEV_MAJOR(CODA_PSDEV_MAJOR);
MODULE_LICENSE("GPL");
MODULE_VERSION("6.6");

static int __init init_coda(void)
{
    int status;
    int i;

    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++)
        device_destroy(coda_psdev_class, MKDEV(CODA_PSDEV_MAJOR, i));
    class_destroy(coda_psdev_class);
    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++)
        device_destroy(coda_psdev_class, MKDEV(CODA_PSDEV_MAJOR, i));
    class_destroy(coda_psdev_class);
    unregister_chrdev(CODA_PSDEV_MAJOR, "coda");
    coda_sysctl_clean();
    coda_destroy_inodecache();
}

module_init(init_coda);
module_exit(exit_coda);