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