Root/fs/coda/psdev.c

1/*
2 * An implementation of a loadable kernel mode driver providing
3 * multiple kernel/user space bidirectional communications links.
4 *
5 * Author: Alan Cox <alan@lxorguk.ukuu.org.uk>
6 *
7 * This program is free software; you can redistribute it and/or
8 * modify it under the terms of the GNU General Public License
9 * as published by the Free Software Foundation; either version
10 * 2 of the License, or (at your option) any later version.
11 *
12 * Adapted to become the Linux 2.0 Coda pseudo device
13 * Peter Braam <braam@maths.ox.ac.uk>
14 * Michael Callahan <mjc@emmy.smith.edu>
15 *
16 * Changes for Linux 2.1
17 * Copyright (c) 1997 Carnegie-Mellon University
18 */
19
20#include <linux/module.h>
21#include <linux/errno.h>
22#include <linux/kernel.h>
23#include <linux/major.h>
24#include <linux/time.h>
25#include <linux/sched.h>
26#include <linux/slab.h>
27#include <linux/ioport.h>
28#include <linux/fcntl.h>
29#include <linux/delay.h>
30#include <linux/skbuff.h>
31#include <linux/proc_fs.h>
32#include <linux/vmalloc.h>
33#include <linux/fs.h>
34#include <linux/file.h>
35#include <linux/poll.h>
36#include <linux/init.h>
37#include <linux/list.h>
38#include <linux/mutex.h>
39#include <linux/device.h>
40#include <asm/io.h>
41#include <asm/system.h>
42#include <asm/poll.h>
43#include <asm/uaccess.h>
44
45#include <linux/coda.h>
46#include <linux/coda_psdev.h>
47
48#include "coda_linux.h"
49
50#include "coda_int.h"
51
52/* statistics */
53int coda_hard; /* allows signals during upcalls */
54unsigned long coda_timeout = 30; /* .. secs, then signals will dequeue */
55
56
57struct venus_comm coda_comms[MAX_CODADEVS];
58static struct class *coda_psdev_class;
59
60/*
61 * Device operations
62 */
63
64static unsigned int coda_psdev_poll(struct file *file, poll_table * wait)
65{
66        struct venus_comm *vcp = (struct venus_comm *) file->private_data;
67    unsigned int mask = POLLOUT | POLLWRNORM;
68
69    poll_wait(file, &vcp->vc_waitq, wait);
70    mutex_lock(&vcp->vc_mutex);
71    if (!list_empty(&vcp->vc_pending))
72                mask |= POLLIN | POLLRDNORM;
73    mutex_unlock(&vcp->vc_mutex);
74
75    return mask;
76}
77
78static long coda_psdev_ioctl(struct file * filp, unsigned int cmd, unsigned long arg)
79{
80    unsigned int data;
81
82    switch(cmd) {
83    case CIOC_KERNEL_VERSION:
84        data = CODA_KERNEL_VERSION;
85        return put_user(data, (int __user *) arg);
86    default:
87        return -ENOTTY;
88    }
89
90    return 0;
91}
92
93/*
94 * Receive a message written by Venus to the psdev
95 */
96 
97static ssize_t coda_psdev_write(struct file *file, const char __user *buf,
98                size_t nbytes, loff_t *off)
99{
100        struct venus_comm *vcp = (struct venus_comm *) file->private_data;
101        struct upc_req *req = NULL;
102        struct upc_req *tmp;
103    struct list_head *lh;
104    struct coda_in_hdr hdr;
105    ssize_t retval = 0, count = 0;
106    int error;
107
108        /* Peek at the opcode, uniquefier */
109    if (copy_from_user(&hdr, buf, 2 * sizeof(u_long)))
110            return -EFAULT;
111
112        if (DOWNCALL(hdr.opcode)) {
113        union outputArgs *dcbuf;
114        int size = sizeof(*dcbuf);
115
116        if ( nbytes < sizeof(struct coda_out_hdr) ) {
117                printk("coda_downcall opc %d uniq %d, not enough!\n",
118                   hdr.opcode, hdr.unique);
119            count = nbytes;
120            goto out;
121        }
122        if ( nbytes > size ) {
123                printk("Coda: downcall opc %d, uniq %d, too much!",
124                   hdr.opcode, hdr.unique);
125                nbytes = size;
126        }
127        CODA_ALLOC(dcbuf, union outputArgs *, nbytes);
128        if (copy_from_user(dcbuf, buf, nbytes)) {
129            CODA_FREE(dcbuf, nbytes);
130            retval = -EFAULT;
131            goto out;
132        }
133
134        /* what downcall errors does Venus handle ? */
135        error = coda_downcall(vcp, hdr.opcode, dcbuf);
136
137        CODA_FREE(dcbuf, nbytes);
138        if (error) {
139                printk("psdev_write: coda_downcall error: %d\n", error);
140            retval = error;
141            goto out;
142        }
143        count = nbytes;
144        goto out;
145    }
146        
147    /* Look for the message on the processing queue. */
148    mutex_lock(&vcp->vc_mutex);
149    list_for_each(lh, &vcp->vc_processing) {
150        tmp = list_entry(lh, struct upc_req , uc_chain);
151        if (tmp->uc_unique == hdr.unique) {
152            req = tmp;
153            list_del(&req->uc_chain);
154            break;
155        }
156    }
157    mutex_unlock(&vcp->vc_mutex);
158
159    if (!req) {
160        printk("psdev_write: msg (%d, %d) not found\n",
161            hdr.opcode, hdr.unique);
162        retval = -ESRCH;
163        goto out;
164    }
165
166        /* move data into response buffer. */
167    if (req->uc_outSize < nbytes) {
168                printk("psdev_write: too much cnt: %d, cnt: %ld, opc: %d, uniq: %d.\n",
169               req->uc_outSize, (long)nbytes, hdr.opcode, hdr.unique);
170        nbytes = req->uc_outSize; /* don't have more space! */
171    }
172        if (copy_from_user(req->uc_data, buf, nbytes)) {
173        req->uc_flags |= CODA_REQ_ABORT;
174        wake_up(&req->uc_sleep);
175        retval = -EFAULT;
176        goto out;
177    }
178
179    /* adjust outsize. is this useful ?? */
180    req->uc_outSize = nbytes;
181    req->uc_flags |= CODA_REQ_WRITE;
182    count = nbytes;
183
184    /* Convert filedescriptor into a file handle */
185    if (req->uc_opcode == CODA_OPEN_BY_FD) {
186        struct coda_open_by_fd_out *outp =
187            (struct coda_open_by_fd_out *)req->uc_data;
188        if (!outp->oh.result)
189            outp->fh = fget(outp->fd);
190    }
191
192        wake_up(&req->uc_sleep);
193out:
194        return(count ? count : retval);
195}
196
197/*
198 * Read a message from the kernel to Venus
199 */
200
201static ssize_t coda_psdev_read(struct file * file, char __user * buf,
202                   size_t nbytes, loff_t *off)
203{
204    DECLARE_WAITQUEUE(wait, current);
205        struct venus_comm *vcp = (struct venus_comm *) file->private_data;
206        struct upc_req *req;
207    ssize_t retval = 0, count = 0;
208
209    if (nbytes == 0)
210        return 0;
211
212    mutex_lock(&vcp->vc_mutex);
213
214    add_wait_queue(&vcp->vc_waitq, &wait);
215    set_current_state(TASK_INTERRUPTIBLE);
216
217    while (list_empty(&vcp->vc_pending)) {
218        if (file->f_flags & O_NONBLOCK) {
219            retval = -EAGAIN;
220            break;
221        }
222        if (signal_pending(current)) {
223            retval = -ERESTARTSYS;
224            break;
225        }
226        mutex_unlock(&vcp->vc_mutex);
227        schedule();
228        mutex_lock(&vcp->vc_mutex);
229    }
230
231    set_current_state(TASK_RUNNING);
232    remove_wait_queue(&vcp->vc_waitq, &wait);
233
234    if (retval)
235        goto out;
236
237    req = list_entry(vcp->vc_pending.next, struct upc_req,uc_chain);
238    list_del(&req->uc_chain);
239
240    /* Move the input args into userspace */
241    count = req->uc_inSize;
242    if (nbytes < req->uc_inSize) {
243                printk ("psdev_read: Venus read %ld bytes of %d in message\n",
244            (long)nbytes, req->uc_inSize);
245        count = nbytes;
246        }
247
248    if (copy_to_user(buf, req->uc_data, count))
249            retval = -EFAULT;
250        
251    /* If request was not a signal, enqueue and don't free */
252    if (!(req->uc_flags & CODA_REQ_ASYNC)) {
253        req->uc_flags |= CODA_REQ_READ;
254        list_add_tail(&(req->uc_chain), &vcp->vc_processing);
255        goto out;
256    }
257
258    CODA_FREE(req->uc_data, sizeof(struct coda_in_hdr));
259    kfree(req);
260out:
261    mutex_unlock(&vcp->vc_mutex);
262    return (count ? count : retval);
263}
264
265static int coda_psdev_open(struct inode * inode, struct file * file)
266{
267    struct venus_comm *vcp;
268    int idx, err;
269
270    idx = iminor(inode);
271    if (idx < 0 || idx >= MAX_CODADEVS)
272        return -ENODEV;
273
274    err = -EBUSY;
275    vcp = &coda_comms[idx];
276    mutex_lock(&vcp->vc_mutex);
277
278    if (!vcp->vc_inuse) {
279        vcp->vc_inuse++;
280
281        INIT_LIST_HEAD(&vcp->vc_pending);
282        INIT_LIST_HEAD(&vcp->vc_processing);
283        init_waitqueue_head(&vcp->vc_waitq);
284        vcp->vc_sb = NULL;
285        vcp->vc_seq = 0;
286
287        file->private_data = vcp;
288        err = 0;
289    }
290
291    mutex_unlock(&vcp->vc_mutex);
292    return err;
293}
294
295
296static int coda_psdev_release(struct inode * inode, struct file * file)
297{
298    struct venus_comm *vcp = (struct venus_comm *) file->private_data;
299    struct upc_req *req, *tmp;
300
301    if (!vcp || !vcp->vc_inuse ) {
302        printk("psdev_release: Not open.\n");
303        return -1;
304    }
305
306    mutex_lock(&vcp->vc_mutex);
307
308    /* Wakeup clients so they can return. */
309    list_for_each_entry_safe(req, tmp, &vcp->vc_pending, uc_chain) {
310        list_del(&req->uc_chain);
311
312        /* Async requests need to be freed here */
313        if (req->uc_flags & CODA_REQ_ASYNC) {
314            CODA_FREE(req->uc_data, sizeof(struct coda_in_hdr));
315            kfree(req);
316            continue;
317        }
318        req->uc_flags |= CODA_REQ_ABORT;
319        wake_up(&req->uc_sleep);
320    }
321
322    list_for_each_entry_safe(req, tmp, &vcp->vc_processing, uc_chain) {
323        list_del(&req->uc_chain);
324
325        req->uc_flags |= CODA_REQ_ABORT;
326        wake_up(&req->uc_sleep);
327    }
328
329    file->private_data = NULL;
330    vcp->vc_inuse--;
331    mutex_unlock(&vcp->vc_mutex);
332    return 0;
333}
334
335
336static const struct file_operations coda_psdev_fops = {
337    .owner = THIS_MODULE,
338    .read = coda_psdev_read,
339    .write = coda_psdev_write,
340    .poll = coda_psdev_poll,
341    .unlocked_ioctl = coda_psdev_ioctl,
342    .open = coda_psdev_open,
343    .release = coda_psdev_release,
344    .llseek = noop_llseek,
345};
346
347static int init_coda_psdev(void)
348{
349    int i, err = 0;
350    if (register_chrdev(CODA_PSDEV_MAJOR, "coda", &coda_psdev_fops)) {
351              printk(KERN_ERR "coda_psdev: unable to get major %d\n",
352             CODA_PSDEV_MAJOR);
353              return -EIO;
354    }
355    coda_psdev_class = class_create(THIS_MODULE, "coda");
356    if (IS_ERR(coda_psdev_class)) {
357        err = PTR_ERR(coda_psdev_class);
358        goto out_chrdev;
359    }
360    for (i = 0; i < MAX_CODADEVS; i++) {
361        mutex_init(&(&coda_comms[i])->vc_mutex);
362        device_create(coda_psdev_class, NULL,
363                  MKDEV(CODA_PSDEV_MAJOR, i), NULL, "cfs%d", i);
364    }
365    coda_sysctl_init();
366    goto out;
367
368out_chrdev:
369    unregister_chrdev(CODA_PSDEV_MAJOR, "coda");
370out:
371    return err;
372}
373
374MODULE_AUTHOR("Jan Harkes, Peter J. Braam");
375MODULE_DESCRIPTION("Coda Distributed File System VFS interface");
376MODULE_ALIAS_CHARDEV_MAJOR(CODA_PSDEV_MAJOR);
377MODULE_LICENSE("GPL");
378MODULE_VERSION("6.6");
379
380static int __init init_coda(void)
381{
382    int status;
383    int i;
384
385    status = coda_init_inodecache();
386    if (status)
387        goto out2;
388    status = init_coda_psdev();
389    if ( status ) {
390        printk("Problem (%d) in init_coda_psdev\n", status);
391        goto out1;
392    }
393    
394    status = register_filesystem(&coda_fs_type);
395    if (status) {
396        printk("coda: failed to register filesystem!\n");
397        goto out;
398    }
399    return 0;
400out:
401    for (i = 0; i < MAX_CODADEVS; i++)
402        device_destroy(coda_psdev_class, MKDEV(CODA_PSDEV_MAJOR, i));
403    class_destroy(coda_psdev_class);
404    unregister_chrdev(CODA_PSDEV_MAJOR, "coda");
405    coda_sysctl_clean();
406out1:
407    coda_destroy_inodecache();
408out2:
409    return status;
410}
411
412static void __exit exit_coda(void)
413{
414        int err, i;
415
416    err = unregister_filesystem(&coda_fs_type);
417        if ( err != 0 ) {
418                printk("coda: failed to unregister filesystem\n");
419        }
420    for (i = 0; i < MAX_CODADEVS; i++)
421        device_destroy(coda_psdev_class, MKDEV(CODA_PSDEV_MAJOR, i));
422    class_destroy(coda_psdev_class);
423    unregister_chrdev(CODA_PSDEV_MAJOR, "coda");
424    coda_sysctl_clean();
425    coda_destroy_inodecache();
426}
427
428module_init(init_coda);
429module_exit(exit_coda);
430
431

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