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/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/devfs_fs_kernel.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/smp_lock.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 #include <linux/coda_proc.h>
  50
  51 #define upc_free(r) kfree(r)
  52
  53 /*
  54  * Coda stuff
  55  */
  56 extern struct file_system_type coda_fs_type;
  57
  58 /* statistics */
  59 int           coda_hard;         /* allows signals during upcalls */
  60 unsigned long coda_timeout = 30; /* .. secs, then signals will dequeue */
  61
  62
  63 struct venus_comm coda_comms[MAX_CODADEVS];
  64 static struct class *coda_psdev_class;
  65
  66 /*
  67  * Device operations
  68  */
  69
  70 static unsigned int coda_psdev_poll(struct file *file, poll_table * wait)
  71 {
  72         struct venus_comm *vcp = (struct venus_comm *) file->private_data;
  73         unsigned int mask = POLLOUT | POLLWRNORM;
  74
  75         poll_wait(file, &vcp->vc_waitq, wait);
  76         if (!list_empty(&vcp->vc_pending))
  77                 mask |= POLLIN | POLLRDNORM;
  78
  79         return mask;
  80 }
  81
  82 static int coda_psdev_ioctl(struct inode * inode, struct file * filp,
  83                             unsigned int cmd, unsigned long arg)
  84 {
  85         unsigned int data;
  86
  87         switch(cmd) {
  88         case CIOC_KERNEL_VERSION:
  89                 data = CODA_KERNEL_VERSION;
  90                 return put_user(data, (int __user *) arg);
  91         default:
  92                 return -ENOTTY;
  93         }
  94
  95         return 0;
  96 }
  97
  98 /*
  99  *      Receive a message written by Venus to the psdev
 100  */
 101
 102 static ssize_t coda_psdev_write(struct file *file, const char __user *buf,
 103                                 size_t nbytes, loff_t *off)
 104 {
 105         struct venus_comm *vcp = (struct venus_comm *) file->private_data;
 106         struct upc_req *req = NULL;
 107         struct upc_req *tmp;
 108         struct list_head *lh;
 109         struct coda_in_hdr hdr;
 110         ssize_t retval = 0, count = 0;
 111         int error;
 112
 113         /* Peek at the opcode, uniquefier */
 114         if (copy_from_user(&hdr, buf, 2 * sizeof(u_long)))
 115                 return -EFAULT;
 116
 117         if (DOWNCALL(hdr.opcode)) {
 118                 struct super_block *sb = NULL;
 119                 union outputArgs *dcbuf;
 120                 int size = sizeof(*dcbuf);
 121
 122                 sb = vcp->vc_sb;
 123                 if ( !sb ) {
 124                         count = nbytes;
 125                         goto out;
 126                 }
 127
 128                 if  ( nbytes < sizeof(struct coda_out_hdr) ) {
 129                         printk("coda_downcall opc %d uniq %d, not enough!\n",
 130                                hdr.opcode, hdr.unique);
 131                         count = nbytes;
 132                         goto out;
 133                 }
 134                 if ( nbytes > size ) {
 135                         printk("Coda: downcall opc %d, uniq %d, too much!",
 136                                hdr.opcode, hdr.unique);
 137                         nbytes = size;
 138                 }
 139                 CODA_ALLOC(dcbuf, union outputArgs *, nbytes);
 140                 if (copy_from_user(dcbuf, buf, nbytes)) {
 141                         CODA_FREE(dcbuf, nbytes);
 142                         retval = -EFAULT;
 143                         goto out;
 144                 }
 145
 146                 /* what downcall errors does Venus handle ? */
 147                 lock_kernel();
 148                 error = coda_downcall(hdr.opcode, dcbuf, sb);
 149                 unlock_kernel();
 150
 151                 CODA_FREE(dcbuf, nbytes);
 152                 if (error) {
 153                         printk("psdev_write: coda_downcall error: %d\n", error);
 154                         retval = error;
 155                         goto out;
 156                 }
 157                 count = nbytes;
 158                 goto out;
 159         }
 160
 161         /* Look for the message on the processing queue. */
 162         lock_kernel();
 163         list_for_each(lh, &vcp->vc_processing) {
 164                 tmp = list_entry(lh, struct upc_req , uc_chain);
 165                 if (tmp->uc_unique == hdr.unique) {
 166                         req = tmp;
 167                         list_del(&req->uc_chain);
 168                         break;
 169                 }
 170         }
 171         unlock_kernel();
 172
 173         if (!req) {
 174                 printk("psdev_write: msg (%d, %d) not found\n",
 175                         hdr.opcode, hdr.unique);
 176                 retval = -ESRCH;
 177                 goto out;
 178         }
 179
 180         /* move data into response buffer. */
 181         if (req->uc_outSize < nbytes) {
 182                 printk("psdev_write: too much cnt: %d, cnt: %ld, opc: %d, uniq: %d.\n",
 183                        req->uc_outSize, (long)nbytes, hdr.opcode, hdr.unique);
 184                 nbytes = req->uc_outSize; /* don't have more space! */
 185         }
 186         if (copy_from_user(req->uc_data, buf, nbytes)) {
 187                 req->uc_flags |= REQ_ABORT;
 188                 wake_up(&req->uc_sleep);
 189                 retval = -EFAULT;
 190                 goto out;
 191         }
 192
 193         /* adjust outsize. is this useful ?? */
 194         req->uc_outSize = nbytes;
 195         req->uc_flags |= REQ_WRITE;
 196         count = nbytes;
 197
 198         /* Convert filedescriptor into a file handle */
 199         if (req->uc_opcode == CODA_OPEN_BY_FD) {
 200                 struct coda_open_by_fd_out *outp =
 201                         (struct coda_open_by_fd_out *)req->uc_data;
 202                 outp->fh = fget(outp->fd);
 203         }
 204
 205         wake_up(&req->uc_sleep);
 206 out:
 207         return(count ? count : retval);
 208 }
 209
 210 /*
 211  *      Read a message from the kernel to Venus
 212  */
 213
 214 static ssize_t coda_psdev_read(struct file * file, char __user * buf,
 215                                size_t nbytes, loff_t *off)
 216 {
 217         DECLARE_WAITQUEUE(wait, current);
 218         struct venus_comm *vcp = (struct venus_comm *) file->private_data;
 219         struct upc_req *req;
 220         ssize_t retval = 0, count = 0;
 221
 222         if (nbytes == 0)
 223                 return 0;
 224
 225         lock_kernel();
 226
 227         add_wait_queue(&vcp->vc_waitq, &wait);
 228         set_current_state(TASK_INTERRUPTIBLE);
 229
 230         while (list_empty(&vcp->vc_pending)) {
 231                 if (file->f_flags & O_NONBLOCK) {
 232                         retval = -EAGAIN;
 233                         break;
 234                 }
 235                 if (signal_pending(current)) {
 236                         retval = -ERESTARTSYS;
 237                         break;
 238                 }
 239                 schedule();
 240         }
 241
 242         set_current_state(TASK_RUNNING);
 243         remove_wait_queue(&vcp->vc_waitq, &wait);
 244
 245         if (retval)
 246                 goto out;
 247
 248         req = list_entry(vcp->vc_pending.next, struct upc_req,uc_chain);
 249         list_del(&req->uc_chain);
 250
 251         /* Move the input args into userspace */
 252         count = req->uc_inSize;
 253         if (nbytes < req->uc_inSize) {
 254                 printk ("psdev_read: Venus read %ld bytes of %d in message\n",
 255                         (long)nbytes, req->uc_inSize);
 256                 count = nbytes;
 257         }
 258
 259         if (copy_to_user(buf, req->uc_data, count))
 260                 retval = -EFAULT;
 261
 262         /* If request was not a signal, enqueue and don't free */
 263         if (!(req->uc_flags & REQ_ASYNC)) {
 264                 req->uc_flags |= REQ_READ;
 265                 list_add(&(req->uc_chain), vcp->vc_processing.prev);
 266                 goto out;
 267         }
 268
 269         CODA_FREE(req->uc_data, sizeof(struct coda_in_hdr));
 270         upc_free(req);
 271 out:
 272         unlock_kernel();
 273         return (count ? count : retval);
 274 }
 275
 276 static int coda_psdev_open(struct inode * inode, struct file * file)
 277 {
 278         struct venus_comm *vcp;
 279         int idx;
 280
 281         lock_kernel();
 282         idx = iminor(inode);
 283         if(idx >= MAX_CODADEVS) {
 284                 unlock_kernel();
 285                 return -ENODEV;
 286         }
 287
 288         vcp = &coda_comms[idx];
 289         if(vcp->vc_inuse) {
 290                 unlock_kernel();
 291                 return -EBUSY;
 292         }
 293
 294         if (!vcp->vc_inuse++) {
 295                 INIT_LIST_HEAD(&vcp->vc_pending);
 296                 INIT_LIST_HEAD(&vcp->vc_processing);
 297                 init_waitqueue_head(&vcp->vc_waitq);
 298                 vcp->vc_sb = NULL;
 299                 vcp->vc_seq = 0;
 300         }
 301
 302         file->private_data = vcp;
 303
 304         unlock_kernel();
 305         return 0;
 306 }
 307
 308
 309 static int coda_psdev_release(struct inode * inode, struct file * file)
 310 {
 311         struct venus_comm *vcp = (struct venus_comm *) file->private_data;
 312         struct upc_req *req, *tmp;
 313
 314         lock_kernel();
 315         if ( !vcp->vc_inuse ) {
 316                 unlock_kernel();
 317                 printk("psdev_release: Not open.\n");
 318                 return -1;
 319         }
 320
 321         if (--vcp->vc_inuse) {
 322                 unlock_kernel();
 323                 return 0;
 324         }
 325
 326         /* Wakeup clients so they can return. */
 327         list_for_each_entry_safe(req, tmp, &vcp->vc_pending, uc_chain) {
 328                 /* Async requests need to be freed here */
 329                 if (req->uc_flags & REQ_ASYNC) {
 330                         CODA_FREE(req->uc_data, sizeof(struct coda_in_hdr));
 331                         upc_free(req);
 332                         continue;
 333                 }
 334                 req->uc_flags |= REQ_ABORT;
 335                 wake_up(&req->uc_sleep);
 336         }
 337
 338         list_for_each_entry(req, &vcp->vc_processing, uc_chain) {
 339                 req->uc_flags |= REQ_ABORT;
 340                 wake_up(&req->uc_sleep);
 341         }
 342
 343         unlock_kernel();
 344         return 0;
 345 }
 346
 347
 348 static struct file_operations coda_psdev_fops = {
 349         .owner          = THIS_MODULE,
 350         .read           = coda_psdev_read,
 351         .write          = coda_psdev_write,
 352         .poll           = coda_psdev_poll,
 353         .ioctl          = coda_psdev_ioctl,
 354         .open           = coda_psdev_open,
 355         .release        = coda_psdev_release,
 356 };
 357
 358 static int init_coda_psdev(void)
 359 {
 360         int i, err = 0;
 361         if (register_chrdev(CODA_PSDEV_MAJOR, "coda", &coda_psdev_fops)) {
 362               printk(KERN_ERR "coda_psdev: unable to get major %d\n",
 363                      CODA_PSDEV_MAJOR);
 364               return -EIO;
 365         }
 366         coda_psdev_class = class_create(THIS_MODULE, "coda");
 367         if (IS_ERR(coda_psdev_class)) {
 368                 err = PTR_ERR(coda_psdev_class);
 369                 goto out_chrdev;
 370         }
 371         devfs_mk_dir ("coda");
 372         for (i = 0; i < MAX_CODADEVS; i++) {
 373                 class_device_create(coda_psdev_class, MKDEV(CODA_PSDEV_MAJOR,i),
 374                                 NULL, "cfs%d", i);
 375                 err = devfs_mk_cdev(MKDEV(CODA_PSDEV_MAJOR, i),
 376                                 S_IFCHR|S_IRUSR|S_IWUSR, "coda/%d", i);
 377                 if (err)
 378                         goto out_class;
 379         }
 380         coda_sysctl_init();
 381         goto out;
 382
 383 out_class:
 384         for (i = 0; i < MAX_CODADEVS; i++)
 385                 class_device_destroy(coda_psdev_class, MKDEV(CODA_PSDEV_MAJOR, i));
 386         class_destroy(coda_psdev_class);
 387 out_chrdev:
 388         unregister_chrdev(CODA_PSDEV_MAJOR, "coda");
 389 out:
 390         return err;
 391 }
 392
 393
 394 MODULE_AUTHOR("Peter J. Braam <braam@cs.cmu.edu>");
 395 MODULE_LICENSE("GPL");
 396
 397 extern int coda_init_inodecache(void);
 398 extern void coda_destroy_inodecache(void);
 399 static int __init init_coda(void)
 400 {
 401         int status;
 402         int i;
 403         printk(KERN_INFO "Coda Kernel/Venus communications, "
 404 #ifdef CONFIG_CODA_FS_OLD_API
 405                "v5.3.20"
 406 #else
 407                "v6.0.0"
 408 #endif
 409                ", coda@cs.cmu.edu\n");
 410
 411         status = coda_init_inodecache();
 412         if (status)
 413                 goto out2;
 414         status = init_coda_psdev();
 415         if ( status ) {
 416                 printk("Problem (%d) in init_coda_psdev\n", status);
 417                 goto out1;
 418         }
 419
 420         status = register_filesystem(&coda_fs_type);
 421         if (status) {
 422                 printk("coda: failed to register filesystem!\n");
 423                 goto out;
 424         }
 425         return 0;
 426 out:
 427         for (i = 0; i < MAX_CODADEVS; i++) {
 428                 class_device_destroy(coda_psdev_class, MKDEV(CODA_PSDEV_MAJOR, i));
 429                 devfs_remove("coda/%d", i);
 430         }
 431         class_destroy(coda_psdev_class);
 432         devfs_remove("coda");
 433         unregister_chrdev(CODA_PSDEV_MAJOR, "coda");
 434         coda_sysctl_clean();
 435 out1:
 436         coda_destroy_inodecache();
 437 out2:
 438         return status;
 439 }
 440
 441 static void __exit exit_coda(void)
 442 {
 443         int err, i;
 444
 445         err = unregister_filesystem(&coda_fs_type);
 446         if ( err != 0 ) {
 447                 printk("coda: failed to unregister filesystem\n");
 448         }
 449         for (i = 0; i < MAX_CODADEVS; i++) {
 450                 class_device_destroy(coda_psdev_class, MKDEV(CODA_PSDEV_MAJOR, i));
 451                 devfs_remove("coda/%d", i);
 452         }
 453         class_destroy(coda_psdev_class);
 454         devfs_remove("coda");
 455         unregister_chrdev(CODA_PSDEV_MAJOR, "coda");
 456         coda_sysctl_clean();
 457         coda_destroy_inodecache();
 458 }
 459
 460 module_init(init_coda);
 461 module_exit(exit_coda);
 462