xref: /openbmc/linux/fs/coda/psdev.c (revision 5f5bac82) 
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/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 
49 #include "coda_int.h"
50 
51 /* statistics */
52 int           coda_hard;         /* allows signals during upcalls */
53 unsigned long coda_timeout = 30; /* .. secs, then signals will dequeue */
54 
55 
56 struct venus_comm coda_comms[MAX_CODADEVS];
57 static struct class *coda_psdev_class;
58 
59 /*
60  * Device operations
61  */
62 
63 static unsigned int coda_psdev_poll(struct file *file, poll_table * wait)
64 {
65         struct venus_comm *vcp = (struct venus_comm *) file->private_data;
66 	unsigned int mask = POLLOUT | POLLWRNORM;
67 
68 	poll_wait(file, &vcp->vc_waitq, wait);
69 	if (!list_empty(&vcp->vc_pending))
70                 mask |= POLLIN | POLLRDNORM;
71 
72 	return mask;
73 }
74 
75 static int coda_psdev_ioctl(struct inode * inode, struct file * filp,
76 			    unsigned int cmd, unsigned long arg)
77 {
78 	unsigned int data;
79 
80 	switch(cmd) {
81 	case CIOC_KERNEL_VERSION:
82 		data = CODA_KERNEL_VERSION;
83 		return put_user(data, (int __user *) arg);
84 	default:
85 		return -ENOTTY;
86 	}
87 
88 	return 0;
89 }
90 
91 /*
92  *	Receive a message written by Venus to the psdev
93  */
94 
95 static ssize_t coda_psdev_write(struct file *file, const char __user *buf,
96 				size_t nbytes, loff_t *off)
97 {
98         struct venus_comm *vcp = (struct venus_comm *) file->private_data;
99         struct upc_req *req = NULL;
100         struct upc_req *tmp;
101 	struct list_head *lh;
102 	struct coda_in_hdr hdr;
103 	ssize_t retval = 0, count = 0;
104 	int error;
105 
106         /* Peek at the opcode, uniquefier */
107 	if (copy_from_user(&hdr, buf, 2 * sizeof(u_long)))
108 	        return -EFAULT;
109 
110         if (DOWNCALL(hdr.opcode)) {
111 		struct super_block *sb = NULL;
112                 union outputArgs *dcbuf;
113 		int size = sizeof(*dcbuf);
114 
115 		sb = vcp->vc_sb;
116 		if ( !sb ) {
117                         count = nbytes;
118                         goto out;
119 		}
120 
121 		if  ( nbytes < sizeof(struct coda_out_hdr) ) {
122 		        printk("coda_downcall opc %d uniq %d, not enough!\n",
123 			       hdr.opcode, hdr.unique);
124 			count = nbytes;
125 			goto out;
126 		}
127 		if ( nbytes > size ) {
128 		        printk("Coda: downcall opc %d, uniq %d, too much!",
129 			       hdr.opcode, hdr.unique);
130 		        nbytes = size;
131 		}
132 		CODA_ALLOC(dcbuf, union outputArgs *, nbytes);
133 		if (copy_from_user(dcbuf, buf, nbytes)) {
134 			CODA_FREE(dcbuf, nbytes);
135 			retval = -EFAULT;
136 			goto out;
137 		}
138 
139 		/* what downcall errors does Venus handle ? */
140 		lock_kernel();
141 		error = coda_downcall(hdr.opcode, dcbuf, sb);
142 		unlock_kernel();
143 
144 		CODA_FREE(dcbuf, nbytes);
145 		if (error) {
146 		        printk("psdev_write: coda_downcall error: %d\n", error);
147 			retval = error;
148 			goto out;
149 		}
150 		count = nbytes;
151 		goto out;
152 	}
153 
154 	/* Look for the message on the processing queue. */
155 	lock_kernel();
156 	list_for_each(lh, &vcp->vc_processing) {
157 		tmp = list_entry(lh, struct upc_req , uc_chain);
158 		if (tmp->uc_unique == hdr.unique) {
159 			req = tmp;
160 			list_del(&req->uc_chain);
161 			break;
162 		}
163 	}
164 	unlock_kernel();
165 
166 	if (!req) {
167 		printk("psdev_write: msg (%d, %d) not found\n",
168 			hdr.opcode, hdr.unique);
169 		retval = -ESRCH;
170 		goto out;
171 	}
172 
173         /* move data into response buffer. */
174 	if (req->uc_outSize < nbytes) {
175                 printk("psdev_write: too much cnt: %d, cnt: %ld, opc: %d, uniq: %d.\n",
176 		       req->uc_outSize, (long)nbytes, hdr.opcode, hdr.unique);
177 		nbytes = req->uc_outSize; /* don't have more space! */
178 	}
179         if (copy_from_user(req->uc_data, buf, nbytes)) {
180 		req->uc_flags |= REQ_ABORT;
181 		wake_up(&req->uc_sleep);
182 		retval = -EFAULT;
183 		goto out;
184 	}
185 
186 	/* adjust outsize. is this useful ?? */
187         req->uc_outSize = nbytes;
188         req->uc_flags |= REQ_WRITE;
189 	count = nbytes;
190 
191 	/* Convert filedescriptor into a file handle */
192 	if (req->uc_opcode == CODA_OPEN_BY_FD) {
193 		struct coda_open_by_fd_out *outp =
194 			(struct coda_open_by_fd_out *)req->uc_data;
195 		if (!outp->oh.result)
196 			outp->fh = fget(outp->fd);
197 	}
198 
199         wake_up(&req->uc_sleep);
200 out:
201         return(count ? count : retval);
202 }
203 
204 /*
205  *	Read a message from the kernel to Venus
206  */
207 
208 static ssize_t coda_psdev_read(struct file * file, char __user * buf,
209 			       size_t nbytes, loff_t *off)
210 {
211 	DECLARE_WAITQUEUE(wait, current);
212         struct venus_comm *vcp = (struct venus_comm *) file->private_data;
213         struct upc_req *req;
214 	ssize_t retval = 0, count = 0;
215 
216 	if (nbytes == 0)
217 		return 0;
218 
219 	lock_kernel();
220 
221 	add_wait_queue(&vcp->vc_waitq, &wait);
222 	set_current_state(TASK_INTERRUPTIBLE);
223 
224 	while (list_empty(&vcp->vc_pending)) {
225 		if (file->f_flags & O_NONBLOCK) {
226 			retval = -EAGAIN;
227 			break;
228 		}
229 		if (signal_pending(current)) {
230 			retval = -ERESTARTSYS;
231 			break;
232 		}
233 		schedule();
234 	}
235 
236 	set_current_state(TASK_RUNNING);
237 	remove_wait_queue(&vcp->vc_waitq, &wait);
238 
239 	if (retval)
240 		goto out;
241 
242 	req = list_entry(vcp->vc_pending.next, struct upc_req,uc_chain);
243 	list_del(&req->uc_chain);
244 
245 	/* Move the input args into userspace */
246 	count = req->uc_inSize;
247 	if (nbytes < req->uc_inSize) {
248                 printk ("psdev_read: Venus read %ld bytes of %d in message\n",
249 			(long)nbytes, req->uc_inSize);
250 		count = nbytes;
251         }
252 
253 	if (copy_to_user(buf, req->uc_data, count))
254 	        retval = -EFAULT;
255 
256 	/* If request was not a signal, enqueue and don't free */
257 	if (!(req->uc_flags & REQ_ASYNC)) {
258 		req->uc_flags |= REQ_READ;
259 		list_add_tail(&(req->uc_chain), &vcp->vc_processing);
260 		goto out;
261 	}
262 
263 	CODA_FREE(req->uc_data, sizeof(struct coda_in_hdr));
264 	kfree(req);
265 out:
266 	unlock_kernel();
267 	return (count ? count : retval);
268 }
269 
270 static int coda_psdev_open(struct inode * inode, struct file * file)
271 {
272 	struct venus_comm *vcp;
273 	int idx, err;
274 
275 	idx = iminor(inode);
276 	if (idx < 0 || idx >= MAX_CODADEVS)
277 		return -ENODEV;
278 
279 	lock_kernel();
280 
281 	err = -EBUSY;
282 	vcp = &coda_comms[idx];
283 	if (!vcp->vc_inuse) {
284 		vcp->vc_inuse++;
285 
286 		INIT_LIST_HEAD(&vcp->vc_pending);
287 		INIT_LIST_HEAD(&vcp->vc_processing);
288 		init_waitqueue_head(&vcp->vc_waitq);
289 		vcp->vc_sb = NULL;
290 		vcp->vc_seq = 0;
291 
292 		file->private_data = vcp;
293 		err = 0;
294 	}
295 
296 	unlock_kernel();
297 	return err;
298 }
299 
300 
301 static int coda_psdev_release(struct inode * inode, struct file * file)
302 {
303 	struct venus_comm *vcp = (struct venus_comm *) file->private_data;
304 	struct upc_req *req, *tmp;
305 
306 	if (!vcp || !vcp->vc_inuse ) {
307 		printk("psdev_release: Not open.\n");
308 		return -1;
309 	}
310 
311 	lock_kernel();
312 
313 	/* Wakeup clients so they can return. */
314 	list_for_each_entry_safe(req, tmp, &vcp->vc_pending, uc_chain) {
315 		list_del(&req->uc_chain);
316 
317 		/* Async requests need to be freed here */
318 		if (req->uc_flags & REQ_ASYNC) {
319 			CODA_FREE(req->uc_data, sizeof(struct coda_in_hdr));
320 			kfree(req);
321 			continue;
322 		}
323 		req->uc_flags |= REQ_ABORT;
324 		wake_up(&req->uc_sleep);
325 	}
326 
327 	list_for_each_entry_safe(req, tmp, &vcp->vc_processing, uc_chain) {
328 		list_del(&req->uc_chain);
329 
330 		req->uc_flags |= REQ_ABORT;
331 		wake_up(&req->uc_sleep);
332 	}
333 
334 	file->private_data = NULL;
335 	vcp->vc_inuse--;
336 	unlock_kernel();
337 	return 0;
338 }
339 
340 
341 static const struct file_operations coda_psdev_fops = {
342 	.owner		= THIS_MODULE,
343 	.read		= coda_psdev_read,
344 	.write		= coda_psdev_write,
345 	.poll		= coda_psdev_poll,
346 	.ioctl		= coda_psdev_ioctl,
347 	.open		= coda_psdev_open,
348 	.release	= coda_psdev_release,
349 };
350 
351 static int init_coda_psdev(void)
352 {
353 	int i, err = 0;
354 	if (register_chrdev(CODA_PSDEV_MAJOR, "coda", &coda_psdev_fops)) {
355               printk(KERN_ERR "coda_psdev: unable to get major %d\n",
356 		     CODA_PSDEV_MAJOR);
357               return -EIO;
358 	}
359 	coda_psdev_class = class_create(THIS_MODULE, "coda");
360 	if (IS_ERR(coda_psdev_class)) {
361 		err = PTR_ERR(coda_psdev_class);
362 		goto out_chrdev;
363 	}
364 	for (i = 0; i < MAX_CODADEVS; i++)
365 		device_create(coda_psdev_class, NULL,
366 			      MKDEV(CODA_PSDEV_MAJOR, i), NULL, "cfs%d", i);
367 	coda_sysctl_init();
368 	goto out;
369 
370 out_chrdev:
371 	unregister_chrdev(CODA_PSDEV_MAJOR, "coda");
372 out:
373 	return err;
374 }
375 
376 MODULE_AUTHOR("Jan Harkes, Peter J. Braam");
377 MODULE_DESCRIPTION("Coda Distributed File System VFS interface");
378 MODULE_ALIAS_CHARDEV_MAJOR(CODA_PSDEV_MAJOR);
379 MODULE_LICENSE("GPL");
380 MODULE_VERSION("6.6");
381 
382 static int __init init_coda(void)
383 {
384 	int status;
385 	int i;
386 
387 	status = coda_init_inodecache();
388 	if (status)
389 		goto out2;
390 	status = init_coda_psdev();
391 	if ( status ) {
392 		printk("Problem (%d) in init_coda_psdev\n", status);
393 		goto out1;
394 	}
395 
396 	status = register_filesystem(&coda_fs_type);
397 	if (status) {
398 		printk("coda: failed to register filesystem!\n");
399 		goto out;
400 	}
401 	return 0;
402 out:
403 	for (i = 0; i < MAX_CODADEVS; i++)
404 		device_destroy(coda_psdev_class, MKDEV(CODA_PSDEV_MAJOR, i));
405 	class_destroy(coda_psdev_class);
406 	unregister_chrdev(CODA_PSDEV_MAJOR, "coda");
407 	coda_sysctl_clean();
408 out1:
409 	coda_destroy_inodecache();
410 out2:
411 	return status;
412 }
413 
414 static void __exit exit_coda(void)
415 {
416         int err, i;
417 
418 	err = unregister_filesystem(&coda_fs_type);
419         if ( err != 0 ) {
420                 printk("coda: failed to unregister filesystem\n");
421         }
422 	for (i = 0; i < MAX_CODADEVS; i++)
423 		device_destroy(coda_psdev_class, MKDEV(CODA_PSDEV_MAJOR, i));
424 	class_destroy(coda_psdev_class);
425 	unregister_chrdev(CODA_PSDEV_MAJOR, "coda");
426 	coda_sysctl_clean();
427 	coda_destroy_inodecache();
428 }
429 
430 module_init(init_coda);
431 module_exit(exit_coda);
432 
433