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 */
55int           coda_hard;         /* allows signals during upcalls */
56unsigned long coda_timeout = 30; /* .. secs, then signals will dequeue */
57
58
59struct venus_comm coda_comms[MAX_CODADEVS];
60static struct class *coda_psdev_class;
61
62/*
63 * Device operations
64 */
65
66static 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
78static 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
98static 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);
202out:
203        return(count ? count : retval);
204}
205
206/*
207 *	Read a message from the kernel to Venus
208 */
209
210static 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);
267out:
268	unlock_kernel();
269	return (count ? count : retval);
270}
271
272static 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
305static 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
344static 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
354static 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
373out_chrdev:
374	unregister_chrdev(CODA_PSDEV_MAJOR, "coda");
375out:
376	return err;
377}
378
379
380MODULE_AUTHOR("Peter J. Braam <braam@cs.cmu.edu>");
381MODULE_LICENSE("GPL");
382
383static 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;
410out:
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();
416out1:
417	coda_destroy_inodecache();
418out2:
419	return status;
420}
421
422static 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
438module_init(init_coda);
439module_exit(exit_coda);
440