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