xref: /openbmc/linux/fs/coda/psdev.c (revision e868d61272caa648214046a096e5a6bfc068dc8c)
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/time.h>
25 #include <linux/slab.h>
26 #include <linux/ioport.h>
27 #include <linux/fcntl.h>
28 #include <linux/delay.h>
29 #include <linux/skbuff.h>
30 #include <linux/proc_fs.h>
31 #include <linux/vmalloc.h>
32 #include <linux/fs.h>
33 #include <linux/file.h>
34 #include <linux/poll.h>
35 #include <linux/init.h>
36 #include <linux/list.h>
37 #include <linux/smp_lock.h>
38 #include <linux/device.h>
39 #include <asm/io.h>
40 #include <asm/system.h>
41 #include <asm/poll.h>
42 #include <asm/uaccess.h>
43 
44 #include <linux/coda.h>
45 #include <linux/coda_linux.h>
46 #include <linux/coda_fs_i.h>
47 #include <linux/coda_psdev.h>
48 #include <linux/coda_proc.h>
49 
50 #include "coda_int.h"
51 
52 #define upc_free(r) kfree(r)
53 
54 /* statistics */
55 int           coda_hard;         /* allows signals during upcalls */
56 unsigned long coda_timeout = 30; /* .. secs, then signals will dequeue */
57 
58 
59 struct venus_comm coda_comms[MAX_CODADEVS];
60 static struct class *coda_psdev_class;
61 
62 /*
63  * Device operations
64  */
65 
66 static unsigned int coda_psdev_poll(struct file *file, poll_table * wait)
67 {
68         struct venus_comm *vcp = (struct venus_comm *) file->private_data;
69 	unsigned int mask = POLLOUT | POLLWRNORM;
70 
71 	poll_wait(file, &vcp->vc_waitq, wait);
72 	if (!list_empty(&vcp->vc_pending))
73                 mask |= POLLIN | POLLRDNORM;
74 
75 	return mask;
76 }
77 
78 static int coda_psdev_ioctl(struct inode * inode, struct file * filp,
79 			    unsigned int cmd, unsigned long arg)
80 {
81 	unsigned int data;
82 
83 	switch(cmd) {
84 	case CIOC_KERNEL_VERSION:
85 		data = CODA_KERNEL_VERSION;
86 		return put_user(data, (int __user *) arg);
87 	default:
88 		return -ENOTTY;
89 	}
90 
91 	return 0;
92 }
93 
94 /*
95  *	Receive a message written by Venus to the psdev
96  */
97 
98 static ssize_t coda_psdev_write(struct file *file, const char __user *buf,
99 				size_t nbytes, loff_t *off)
100 {
101         struct venus_comm *vcp = (struct venus_comm *) file->private_data;
102         struct upc_req *req = NULL;
103         struct upc_req *tmp;
104 	struct list_head *lh;
105 	struct coda_in_hdr hdr;
106 	ssize_t retval = 0, count = 0;
107 	int error;
108 
109         /* Peek at the opcode, uniquefier */
110 	if (copy_from_user(&hdr, buf, 2 * sizeof(u_long)))
111 	        return -EFAULT;
112 
113         if (DOWNCALL(hdr.opcode)) {
114 		struct super_block *sb = NULL;
115                 union outputArgs *dcbuf;
116 		int size = sizeof(*dcbuf);
117 
118 		sb = vcp->vc_sb;
119 		if ( !sb ) {
120                         count = nbytes;
121                         goto out;
122 		}
123 
124 		if  ( nbytes < sizeof(struct coda_out_hdr) ) {
125 		        printk("coda_downcall opc %d uniq %d, not enough!\n",
126 			       hdr.opcode, hdr.unique);
127 			count = nbytes;
128 			goto out;
129 		}
130 		if ( nbytes > size ) {
131 		        printk("Coda: downcall opc %d, uniq %d, too much!",
132 			       hdr.opcode, hdr.unique);
133 		        nbytes = size;
134 		}
135 		CODA_ALLOC(dcbuf, union outputArgs *, nbytes);
136 		if (copy_from_user(dcbuf, buf, nbytes)) {
137 			CODA_FREE(dcbuf, nbytes);
138 			retval = -EFAULT;
139 			goto out;
140 		}
141 
142 		/* what downcall errors does Venus handle ? */
143 		lock_kernel();
144 		error = coda_downcall(hdr.opcode, dcbuf, sb);
145 		unlock_kernel();
146 
147 		CODA_FREE(dcbuf, nbytes);
148 		if (error) {
149 		        printk("psdev_write: coda_downcall error: %d\n", error);
150 			retval = error;
151 			goto out;
152 		}
153 		count = nbytes;
154 		goto out;
155 	}
156 
157 	/* Look for the message on the processing queue. */
158 	lock_kernel();
159 	list_for_each(lh, &vcp->vc_processing) {
160 		tmp = list_entry(lh, struct upc_req , uc_chain);
161 		if (tmp->uc_unique == hdr.unique) {
162 			req = tmp;
163 			list_del(&req->uc_chain);
164 			break;
165 		}
166 	}
167 	unlock_kernel();
168 
169 	if (!req) {
170 		printk("psdev_write: msg (%d, %d) not found\n",
171 			hdr.opcode, hdr.unique);
172 		retval = -ESRCH;
173 		goto out;
174 	}
175 
176         /* move data into response buffer. */
177 	if (req->uc_outSize < nbytes) {
178                 printk("psdev_write: too much cnt: %d, cnt: %ld, opc: %d, uniq: %d.\n",
179 		       req->uc_outSize, (long)nbytes, hdr.opcode, hdr.unique);
180 		nbytes = req->uc_outSize; /* don't have more space! */
181 	}
182         if (copy_from_user(req->uc_data, buf, nbytes)) {
183 		req->uc_flags |= REQ_ABORT;
184 		wake_up(&req->uc_sleep);
185 		retval = -EFAULT;
186 		goto out;
187 	}
188 
189 	/* adjust outsize. is this useful ?? */
190         req->uc_outSize = nbytes;
191         req->uc_flags |= REQ_WRITE;
192 	count = nbytes;
193 
194 	/* Convert filedescriptor into a file handle */
195 	if (req->uc_opcode == CODA_OPEN_BY_FD) {
196 		struct coda_open_by_fd_out *outp =
197 			(struct coda_open_by_fd_out *)req->uc_data;
198 		outp->fh = fget(outp->fd);
199 	}
200 
201         wake_up(&req->uc_sleep);
202 out:
203         return(count ? count : retval);
204 }
205 
206 /*
207  *	Read a message from the kernel to Venus
208  */
209 
210 static ssize_t coda_psdev_read(struct file * file, char __user * buf,
211 			       size_t nbytes, loff_t *off)
212 {
213 	DECLARE_WAITQUEUE(wait, current);
214         struct venus_comm *vcp = (struct venus_comm *) file->private_data;
215         struct upc_req *req;
216 	ssize_t retval = 0, count = 0;
217 
218 	if (nbytes == 0)
219 		return 0;
220 
221 	lock_kernel();
222 
223 	add_wait_queue(&vcp->vc_waitq, &wait);
224 	set_current_state(TASK_INTERRUPTIBLE);
225 
226 	while (list_empty(&vcp->vc_pending)) {
227 		if (file->f_flags & O_NONBLOCK) {
228 			retval = -EAGAIN;
229 			break;
230 		}
231 		if (signal_pending(current)) {
232 			retval = -ERESTARTSYS;
233 			break;
234 		}
235 		schedule();
236 	}
237 
238 	set_current_state(TASK_RUNNING);
239 	remove_wait_queue(&vcp->vc_waitq, &wait);
240 
241 	if (retval)
242 		goto out;
243 
244 	req = list_entry(vcp->vc_pending.next, struct upc_req,uc_chain);
245 	list_del(&req->uc_chain);
246 
247 	/* Move the input args into userspace */
248 	count = req->uc_inSize;
249 	if (nbytes < req->uc_inSize) {
250                 printk ("psdev_read: Venus read %ld bytes of %d in message\n",
251 			(long)nbytes, req->uc_inSize);
252 		count = nbytes;
253         }
254 
255 	if (copy_to_user(buf, req->uc_data, count))
256 	        retval = -EFAULT;
257 
258 	/* If request was not a signal, enqueue and don't free */
259 	if (!(req->uc_flags & REQ_ASYNC)) {
260 		req->uc_flags |= REQ_READ;
261 		list_add_tail(&(req->uc_chain), &vcp->vc_processing);
262 		goto out;
263 	}
264 
265 	CODA_FREE(req->uc_data, sizeof(struct coda_in_hdr));
266 	upc_free(req);
267 out:
268 	unlock_kernel();
269 	return (count ? count : retval);
270 }
271 
272 static int coda_psdev_open(struct inode * inode, struct file * file)
273 {
274         struct venus_comm *vcp;
275 	int idx;
276 
277 	lock_kernel();
278 	idx = iminor(inode);
279 	if(idx >= MAX_CODADEVS) {
280 		unlock_kernel();
281 		return -ENODEV;
282 	}
283 
284 	vcp = &coda_comms[idx];
285 	if(vcp->vc_inuse) {
286 		unlock_kernel();
287 		return -EBUSY;
288 	}
289 
290 	if (!vcp->vc_inuse++) {
291 		INIT_LIST_HEAD(&vcp->vc_pending);
292 		INIT_LIST_HEAD(&vcp->vc_processing);
293 		init_waitqueue_head(&vcp->vc_waitq);
294 		vcp->vc_sb = NULL;
295 		vcp->vc_seq = 0;
296 	}
297 
298 	file->private_data = vcp;
299 
300 	unlock_kernel();
301         return 0;
302 }
303 
304 
305 static int coda_psdev_release(struct inode * inode, struct file * file)
306 {
307         struct venus_comm *vcp = (struct venus_comm *) file->private_data;
308         struct upc_req *req, *tmp;
309 
310 	lock_kernel();
311 	if ( !vcp->vc_inuse ) {
312 		unlock_kernel();
313 		printk("psdev_release: Not open.\n");
314 		return -1;
315 	}
316 
317 	if (--vcp->vc_inuse) {
318 		unlock_kernel();
319 		return 0;
320 	}
321 
322         /* Wakeup clients so they can return. */
323 	list_for_each_entry_safe(req, tmp, &vcp->vc_pending, uc_chain) {
324 		/* Async requests need to be freed here */
325 		if (req->uc_flags & REQ_ASYNC) {
326 			CODA_FREE(req->uc_data, sizeof(struct coda_in_hdr));
327 			upc_free(req);
328 			continue;
329 		}
330 		req->uc_flags |= REQ_ABORT;
331 		wake_up(&req->uc_sleep);
332         }
333 
334 	list_for_each_entry(req, &vcp->vc_processing, uc_chain) {
335 		req->uc_flags |= REQ_ABORT;
336 	        wake_up(&req->uc_sleep);
337         }
338 
339 	unlock_kernel();
340 	return 0;
341 }
342 
343 
344 static const struct file_operations coda_psdev_fops = {
345 	.owner		= THIS_MODULE,
346 	.read		= coda_psdev_read,
347 	.write		= coda_psdev_write,
348 	.poll		= coda_psdev_poll,
349 	.ioctl		= coda_psdev_ioctl,
350 	.open		= coda_psdev_open,
351 	.release	= coda_psdev_release,
352 };
353 
354 static int init_coda_psdev(void)
355 {
356 	int i, err = 0;
357 	if (register_chrdev(CODA_PSDEV_MAJOR, "coda", &coda_psdev_fops)) {
358               printk(KERN_ERR "coda_psdev: unable to get major %d\n",
359 		     CODA_PSDEV_MAJOR);
360               return -EIO;
361 	}
362 	coda_psdev_class = class_create(THIS_MODULE, "coda");
363 	if (IS_ERR(coda_psdev_class)) {
364 		err = PTR_ERR(coda_psdev_class);
365 		goto out_chrdev;
366 	}
367 	for (i = 0; i < MAX_CODADEVS; i++)
368 		class_device_create(coda_psdev_class, NULL,
369 				MKDEV(CODA_PSDEV_MAJOR,i), NULL, "cfs%d", i);
370 	coda_sysctl_init();
371 	goto out;
372 
373 out_chrdev:
374 	unregister_chrdev(CODA_PSDEV_MAJOR, "coda");
375 out:
376 	return err;
377 }
378 
379 
380 MODULE_AUTHOR("Peter J. Braam <braam@cs.cmu.edu>");
381 MODULE_LICENSE("GPL");
382 
383 static int __init init_coda(void)
384 {
385 	int status;
386 	int i;
387 	printk(KERN_INFO "Coda Kernel/Venus communications, "
388 #ifdef CONFIG_CODA_FS_OLD_API
389 	       "v5.3.20"
390 #else
391 	       "v6.0.0"
392 #endif
393 	       ", coda@cs.cmu.edu\n");
394 
395 	status = coda_init_inodecache();
396 	if (status)
397 		goto out2;
398 	status = init_coda_psdev();
399 	if ( status ) {
400 		printk("Problem (%d) in init_coda_psdev\n", status);
401 		goto out1;
402 	}
403 
404 	status = register_filesystem(&coda_fs_type);
405 	if (status) {
406 		printk("coda: failed to register filesystem!\n");
407 		goto out;
408 	}
409 	return 0;
410 out:
411 	for (i = 0; i < MAX_CODADEVS; i++)
412 		class_device_destroy(coda_psdev_class, MKDEV(CODA_PSDEV_MAJOR, i));
413 	class_destroy(coda_psdev_class);
414 	unregister_chrdev(CODA_PSDEV_MAJOR, "coda");
415 	coda_sysctl_clean();
416 out1:
417 	coda_destroy_inodecache();
418 out2:
419 	return status;
420 }
421 
422 static void __exit exit_coda(void)
423 {
424         int err, i;
425 
426 	err = unregister_filesystem(&coda_fs_type);
427         if ( err != 0 ) {
428                 printk("coda: failed to unregister filesystem\n");
429         }
430 	for (i = 0; i < MAX_CODADEVS; i++)
431 		class_device_destroy(coda_psdev_class, MKDEV(CODA_PSDEV_MAJOR, i));
432 	class_destroy(coda_psdev_class);
433 	unregister_chrdev(CODA_PSDEV_MAJOR, "coda");
434 	coda_sysctl_clean();
435 	coda_destroy_inodecache();
436 }
437 
438 module_init(init_coda);
439 module_exit(exit_coda);
440 
441