File: /usr/src/linux/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@redhat.com>
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/sched.h>
25 #include <linux/lp.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/devfs_fs_kernel.h>
33 #include <linux/vmalloc.h>
34 #include <linux/fs.h>
35 #include <linux/file.h>
36 #include <linux/poll.h>
37 #include <linux/init.h>
38 #include <linux/list.h>
39 #include <linux/smp_lock.h>
40 #include <asm/io.h>
41 #include <asm/segment.h>
42 #include <asm/system.h>
43 #include <asm/poll.h>
44 #include <asm/uaccess.h>
45
46 #include <linux/coda.h>
47 #include <linux/coda_linux.h>
48 #include <linux/coda_fs_i.h>
49 #include <linux/coda_psdev.h>
50 #include <linux/coda_proc.h>
51
52 #define upc_free(r) kfree(r)
53
54 /*
55 * Coda stuff
56 */
57 extern struct file_system_type coda_fs_type;
58
59 /* statistics */
60 int coda_hard; /* allows signals during upcalls */
61 unsigned long coda_timeout = 30; /* .. secs, then signals will dequeue */
62
63
64 struct venus_comm coda_comms[MAX_CODADEVS];
65 kmem_cache_t *cii_cache, *cred_cache, *upc_cache;
66
67 /*
68 * Device operations
69 */
70
71 static unsigned int coda_psdev_poll(struct file *file, poll_table * wait)
72 {
73 struct venus_comm *vcp = (struct venus_comm *) file->private_data;
74 unsigned int mask = POLLOUT | POLLWRNORM;
75
76 poll_wait(file, &vcp->vc_waitq, wait);
77 if (!list_empty(&vcp->vc_pending))
78 mask |= POLLIN | POLLRDNORM;
79
80 return mask;
81 }
82
83 static int coda_psdev_ioctl(struct inode * inode, struct file * filp,
84 unsigned int cmd, unsigned long arg)
85 {
86 unsigned int data;
87
88 switch(cmd) {
89 case CIOC_KERNEL_VERSION:
90 data = CODA_KERNEL_VERSION;
91 return put_user(data, (int *) arg);
92 default:
93 return -ENOTTY;
94 }
95
96 return 0;
97 }
98
99 /*
100 * Receive a message written by Venus to the psdev
101 */
102
103 static ssize_t coda_psdev_write(struct file *file, const char *buf,
104 size_t nbytes, loff_t *off)
105 {
106 struct venus_comm *vcp = (struct venus_comm *) file->private_data;
107 struct upc_req *req = NULL;
108 struct upc_req *tmp;
109 struct list_head *lh;
110 struct coda_in_hdr hdr;
111 ssize_t retval = 0, count = 0;
112 int error;
113
114 /* Peek at the opcode, uniquefier */
115 if (copy_from_user(&hdr, buf, 2 * sizeof(u_long)))
116 return -EFAULT;
117
118 CDEBUG(D_PSDEV, "(process,opc,uniq)=(%d,%ld,%ld), nbytes %ld\n",
119 current->pid, hdr.opcode, hdr.unique, (long)nbytes);
120
121 if (DOWNCALL(hdr.opcode)) {
122 struct super_block *sb = NULL;
123 union outputArgs *dcbuf;
124 int size = sizeof(*dcbuf);
125
126 sb = vcp->vc_sb;
127 if ( !sb ) {
128 CDEBUG(D_PSDEV, "coda_psdev_write: downcall, no SB!\n");
129 count = nbytes;
130 goto out;
131 }
132 CDEBUG(D_PSDEV, "handling downcall\n");
133
134 if ( nbytes < sizeof(struct coda_out_hdr) ) {
135 printk("coda_downcall opc %ld uniq %ld, not enough!\n",
136 hdr.opcode, hdr.unique);
137 count = nbytes;
138 goto out;
139 }
140 if ( nbytes > size ) {
141 printk("Coda: downcall opc %ld, uniq %ld, too much!",
142 hdr.opcode, hdr.unique);
143 nbytes = size;
144 }
145 CODA_ALLOC(dcbuf, union outputArgs *, nbytes);
146 if (copy_from_user(dcbuf, buf, nbytes)) {
147 CODA_FREE(dcbuf, nbytes);
148 retval = -EFAULT;
149 goto out;
150 }
151
152 /* what downcall errors does Venus handle ? */
153 lock_kernel();
154 error = coda_downcall(hdr.opcode, dcbuf, sb);
155 unlock_kernel();
156
157 CODA_FREE(dcbuf, nbytes);
158 if (error) {
159 printk("psdev_write: coda_downcall error: %d\n", error);
160 retval = error;
161 goto out;
162 }
163 count = nbytes;
164 goto out;
165 }
166
167 /* Look for the message on the processing queue. */
168 lock_kernel();
169 list_for_each(lh, &vcp->vc_processing) {
170 tmp = list_entry(lh, struct upc_req , uc_chain);
171 if (tmp->uc_unique == hdr.unique) {
172 req = tmp;
173 list_del(&req->uc_chain);
174 break;
175 }
176 }
177 unlock_kernel();
178
179 if (!req) {
180 printk("psdev_write: msg (%ld, %ld) not found\n",
181 hdr.opcode, hdr.unique);
182 retval = -ESRCH;
183 goto out;
184 }
185
186 CDEBUG(D_PSDEV,"Eureka: uniq %ld on queue!\n", hdr.unique);
187
188 /* move data into response buffer. */
189 if (req->uc_outSize < nbytes) {
190 printk("psdev_write: too much cnt: %d, cnt: %ld, opc: %ld, uniq: %ld.\n",
191 req->uc_outSize, (long)nbytes, hdr.opcode, hdr.unique);
192 nbytes = req->uc_outSize; /* don't have more space! */
193 }
194 if (copy_from_user(req->uc_data, buf, nbytes)) {
195 req->uc_flags |= REQ_ABORT;
196 wake_up(&req->uc_sleep);
197 retval = -EFAULT;
198 goto out;
199 }
200
201 /* adjust outsize. is this useful ?? */
202 req->uc_outSize = nbytes;
203 req->uc_flags |= REQ_WRITE;
204 count = nbytes;
205
206 /* Convert filedescriptor into a file handle */
207 if (req->uc_opcode == CODA_OPEN_BY_FD) {
208 struct coda_open_by_fd_out *outp =
209 (struct coda_open_by_fd_out *)req->uc_data;
210 outp->fh = fget(outp->fd);
211 }
212
213 CDEBUG(D_PSDEV,
214 "Found! Count %ld for (opc,uniq)=(%ld,%ld), upc_req at %p\n",
215 (long)count, hdr.opcode, hdr.unique, &req);
216
217 wake_up(&req->uc_sleep);
218 out:
219 return(count ? count : retval);
220 }
221
222 /*
223 * Read a message from the kernel to Venus
224 */
225
226 static ssize_t coda_psdev_read(struct file * file, char * buf,
227 size_t nbytes, loff_t *off)
228 {
229 DECLARE_WAITQUEUE(wait, current);
230 struct venus_comm *vcp = (struct venus_comm *) file->private_data;
231 struct upc_req *req;
232 ssize_t retval = 0, count = 0;
233
234 if (nbytes == 0)
235 return 0;
236
237 lock_kernel();
238
239 add_wait_queue(&vcp->vc_waitq, &wait);
240 set_current_state(TASK_INTERRUPTIBLE);
241
242 while (list_empty(&vcp->vc_pending)) {
243 if (file->f_flags & O_NONBLOCK) {
244 retval = -EAGAIN;
245 break;
246 }
247 if (signal_pending(current)) {
248 retval = -ERESTARTSYS;
249 break;
250 }
251 schedule();
252 }
253
254 set_current_state(TASK_RUNNING);
255 remove_wait_queue(&vcp->vc_waitq, &wait);
256
257 if (retval)
258 goto out;
259
260 req = list_entry(vcp->vc_pending.next, struct upc_req,uc_chain);
261 list_del(&req->uc_chain);
262
263 /* Move the input args into userspace */
264 count = req->uc_inSize;
265 if (nbytes < req->uc_inSize) {
266 printk ("psdev_read: Venus read %ld bytes of %d in message\n",
267 (long)nbytes, req->uc_inSize);
268 count = nbytes;
269 }
270
271 if (copy_to_user(buf, req->uc_data, count))
272 retval = -EFAULT;
273
274 /* If request was not a signal, enqueue and don't free */
275 if (!(req->uc_flags & REQ_ASYNC)) {
276 req->uc_flags |= REQ_READ;
277 list_add(&(req->uc_chain), vcp->vc_processing.prev);
278 goto out;
279 }
280
281 CDEBUG(D_PSDEV, "vcread: signal msg (%d, %d)\n",
282 req->uc_opcode, req->uc_unique);
283
284 CODA_FREE(req->uc_data, sizeof(struct coda_in_hdr));
285 upc_free(req);
286 out:
287 unlock_kernel();
288 return (count ? count : retval);
289 }
290
291 static int coda_psdev_open(struct inode * inode, struct file * file)
292 {
293 struct venus_comm *vcp;
294 int idx;
295 ENTRY;
296
297 lock_kernel();
298 idx = MINOR(inode->i_rdev);
299 if(idx >= MAX_CODADEVS) {
300 unlock_kernel();
301 return -ENODEV;
302 }
303
304 vcp = &coda_comms[idx];
305 if(vcp->vc_inuse) {
306 unlock_kernel();
307 return -EBUSY;
308 }
309
310 if (!vcp->vc_inuse++) {
311 INIT_LIST_HEAD(&vcp->vc_pending);
312 INIT_LIST_HEAD(&vcp->vc_processing);
313 init_waitqueue_head(&vcp->vc_waitq);
314 vcp->vc_sb = 0;
315 vcp->vc_seq = 0;
316 }
317
318 file->private_data = vcp;
319
320 CDEBUG(D_PSDEV, "device %i - inuse: %d\n", idx, vcp->vc_inuse);
321
322 EXIT;
323 unlock_kernel();
324 return 0;
325 }
326
327
328 static int coda_psdev_release(struct inode * inode, struct file * file)
329 {
330 struct venus_comm *vcp = (struct venus_comm *) file->private_data;
331 struct upc_req *req;
332 struct list_head *lh, *next;
333 ENTRY;
334
335 lock_kernel();
336 if ( !vcp->vc_inuse ) {
337 unlock_kernel();
338 printk("psdev_release: Not open.\n");
339 return -1;
340 }
341
342 CDEBUG(D_PSDEV, "psdev_release: inuse %d\n", vcp->vc_inuse);
343 if (--vcp->vc_inuse) {
344 unlock_kernel();
345 return 0;
346 }
347
348 /* Wakeup clients so they can return. */
349 CDEBUG(D_PSDEV, "wake up pending clients\n");
350 lh = vcp->vc_pending.next;
351 next = lh;
352 while ( (lh = next) != &vcp->vc_pending) {
353 next = lh->next;
354 req = list_entry(lh, struct upc_req, uc_chain);
355 /* Async requests need to be freed here */
356 if (req->uc_flags & REQ_ASYNC) {
357 CODA_FREE(req->uc_data, sizeof(struct coda_in_hdr));
358 upc_free(req);
359 continue;
360 }
361 req->uc_flags |= REQ_ABORT;
362 wake_up(&req->uc_sleep);
363 }
364
365 lh = &vcp->vc_processing;
366 CDEBUG(D_PSDEV, "wake up processing clients\n");
367 while ( (lh = lh->next) != &vcp->vc_processing) {
368 req = list_entry(lh, struct upc_req, uc_chain);
369 req->uc_flags |= REQ_ABORT;
370 wake_up(&req->uc_sleep);
371 }
372 CDEBUG(D_PSDEV, "Done.\n");
373
374 EXIT;
375 unlock_kernel();
376 return 0;
377 }
378
379
380 static struct file_operations coda_psdev_fops = {
381 owner: THIS_MODULE,
382 read: coda_psdev_read,
383 write: coda_psdev_write,
384 poll: coda_psdev_poll,
385 ioctl: coda_psdev_ioctl,
386 open: coda_psdev_open,
387 release: coda_psdev_release,
388 };
389
390 static devfs_handle_t devfs_handle;
391
392 static int init_coda_psdev(void)
393 {
394 if(devfs_register_chrdev(CODA_PSDEV_MAJOR,"coda_psdev",
395 &coda_psdev_fops)) {
396 printk(KERN_ERR "coda_psdev: unable to get major %d\n",
397 CODA_PSDEV_MAJOR);
398 return -EIO;
399 }
400 devfs_handle = devfs_mk_dir (NULL, "coda", NULL);
401 devfs_register_series (devfs_handle, "%u", MAX_CODADEVS, DEVFS_FL_NONE,
402 CODA_PSDEV_MAJOR, 0,
403 S_IFCHR | S_IRUSR | S_IWUSR,
404 &coda_psdev_fops, NULL);
405
406 coda_sysctl_init();
407
408 return 0;
409 }
410
411
412 MODULE_AUTHOR("Peter J. Braam <braam@cs.cmu.edu>");
413
414 static int __init init_coda(void)
415 {
416 int status;
417 printk(KERN_INFO "Coda Kernel/Venus communications, v5.3.15, coda@cs.cmu.edu\n");
418
419 status = init_coda_psdev();
420 if ( status ) {
421 printk("Problem (%d) in init_coda_psdev\n", status);
422 return status;
423 }
424
425 status = register_filesystem(&coda_fs_type);
426 if (status) {
427 printk("coda: failed to register filesystem!\n");
428 devfs_unregister(devfs_handle);
429 devfs_unregister_chrdev(CODA_PSDEV_MAJOR,"coda_psdev");
430 coda_sysctl_clean();
431 }
432 return status;
433 }
434
435 static void __exit exit_coda(void)
436 {
437 int err;
438
439 ENTRY;
440
441 err = unregister_filesystem(&coda_fs_type);
442 if ( err != 0 ) {
443 printk("coda: failed to unregister filesystem\n");
444 }
445 devfs_unregister(devfs_handle);
446 devfs_unregister_chrdev(CODA_PSDEV_MAJOR, "coda_psdev");
447 coda_sysctl_clean();
448 }
449
450 module_init(init_coda);
451 module_exit(exit_coda);
452
453