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_linux.h>
  47 #include <linux/coda_fs_i.h>
  48 #include <linux/coda_psdev.h>
  49
  50 #include "coda_int.h"
  51
  52 /* statistics */
  53 int           coda_hard;         /* allows signals during upcalls */
  54 unsigned long coda_timeout = 30; /* .. secs, then signals will dequeue */
  55
  56
  57 struct venus_comm coda_comms[MAX_CODADEVS];
  58 static struct class *coda_psdev_class;
  59
  60 /*
  61  * Device operations
  62  */
  63
  64 static 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
  78 static 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
  97 static 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);
 193 out:
 194         return(count ? count : retval);
 195 }
 196
 197 /*
 198  *      Read a message from the kernel to Venus
 199  */
 200
 201 static 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);
 260 out:
 261         mutex_unlock(&vcp->vc_mutex);
 262         return (count ? count : retval);
 263 }
 264
 265 static 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
 296 static 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
 336 static 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
 347 static 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
 368 out_chrdev:
 369         unregister_chrdev(CODA_PSDEV_MAJOR, "coda");
 370 out:
 371         return err;
 372 }
 373
 374 MODULE_AUTHOR("Jan Harkes, Peter J. Braam");
 375 MODULE_DESCRIPTION("Coda Distributed File System VFS interface");
 376 MODULE_ALIAS_CHARDEV_MAJOR(CODA_PSDEV_MAJOR);
 377 MODULE_LICENSE("GPL");
 378 MODULE_VERSION("6.6");
 379
 380 static 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;
 400 out:
 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();
 406 out1:
 407         coda_destroy_inodecache();
 408 out2:
 409         return status;
 410 }
 411
 412 static 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
 428 module_init(init_coda);
 429 module_exit(exit_coda);
 430