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/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
  49 #include "coda_int.h"
  50
  51 /* statistics */
  52 int           coda_hard;         /* allows signals during upcalls */
  53 unsigned long coda_timeout = 30; /* .. secs, then signals will dequeue */
  54
  55
  56 struct venus_comm coda_comms[MAX_CODADEVS];
  57 static struct class *coda_psdev_class;
  58
  59 /*
  60  * Device operations
  61  */
  62
  63 static unsigned int coda_psdev_poll(struct file *file, poll_table * wait)
  64 {
  65         struct venus_comm *vcp = (struct venus_comm *) file->private_data;
  66         unsigned int mask = POLLOUT | POLLWRNORM;
  67
  68         poll_wait(file, &vcp->vc_waitq, wait);
  69         if (!list_empty(&vcp->vc_pending))
  70                 mask |= POLLIN | POLLRDNORM;
  71
  72         return mask;
  73 }
  74
  75 static int coda_psdev_ioctl(struct inode * inode, struct file * filp,
  76                             unsigned int cmd, unsigned long arg)
  77 {
  78         unsigned int data;
  79
  80         switch(cmd) {
  81         case CIOC_KERNEL_VERSION:
  82                 data = CODA_KERNEL_VERSION;
  83                 return put_user(data, (int __user *) arg);
  84         default:
  85                 return -ENOTTY;
  86         }
  87
  88         return 0;
  89 }
  90
  91 /*
  92  *      Receive a message written by Venus to the psdev
  93  */
  94
  95 static ssize_t coda_psdev_write(struct file *file, const char __user *buf,
  96                                 size_t nbytes, loff_t *off)
  97 {
  98         struct venus_comm *vcp = (struct venus_comm *) file->private_data;
  99         struct upc_req *req = NULL;
 100         struct upc_req *tmp;
 101         struct list_head *lh;
 102         struct coda_in_hdr hdr;
 103         ssize_t retval = 0, count = 0;
 104         int error;
 105
 106         /* Peek at the opcode, uniquefier */
 107         if (copy_from_user(&hdr, buf, 2 * sizeof(u_long)))
 108                 return -EFAULT;
 109
 110         if (DOWNCALL(hdr.opcode)) {
 111                 struct super_block *sb = NULL;
 112                 union outputArgs *dcbuf;
 113                 int size = sizeof(*dcbuf);
 114
 115                 sb = vcp->vc_sb;
 116                 if ( !sb ) {
 117                         count = nbytes;
 118                         goto out;
 119                 }
 120
 121                 if  ( nbytes < sizeof(struct coda_out_hdr) ) {
 122                         printk("coda_downcall opc %d uniq %d, not enough!\n",
 123                                hdr.opcode, hdr.unique);
 124                         count = nbytes;
 125                         goto out;
 126                 }
 127                 if ( nbytes > size ) {
 128                         printk("Coda: downcall opc %d, uniq %d, too much!",
 129                                hdr.opcode, hdr.unique);
 130                         nbytes = size;
 131                 }
 132                 CODA_ALLOC(dcbuf, union outputArgs *, nbytes);
 133                 if (copy_from_user(dcbuf, buf, nbytes)) {
 134                         CODA_FREE(dcbuf, nbytes);
 135                         retval = -EFAULT;
 136                         goto out;
 137                 }
 138
 139                 /* what downcall errors does Venus handle ? */
 140                 lock_kernel();
 141                 error = coda_downcall(hdr.opcode, dcbuf, sb);
 142                 unlock_kernel();
 143
 144                 CODA_FREE(dcbuf, nbytes);
 145                 if (error) {
 146                         printk("psdev_write: coda_downcall error: %d\n", error);
 147                         retval = error;
 148                         goto out;
 149                 }
 150                 count = nbytes;
 151                 goto out;
 152         }
 153
 154         /* Look for the message on the processing queue. */
 155         lock_kernel();
 156         list_for_each(lh, &vcp->vc_processing) {
 157                 tmp = list_entry(lh, struct upc_req , uc_chain);
 158                 if (tmp->uc_unique == hdr.unique) {
 159                         req = tmp;
 160                         list_del(&req->uc_chain);
 161                         break;
 162                 }
 163         }
 164         unlock_kernel();
 165
 166         if (!req) {
 167                 printk("psdev_write: msg (%d, %d) not found\n",
 168                         hdr.opcode, hdr.unique);
 169                 retval = -ESRCH;
 170                 goto out;
 171         }
 172
 173         /* move data into response buffer. */
 174         if (req->uc_outSize < nbytes) {
 175                 printk("psdev_write: too much cnt: %d, cnt: %ld, opc: %d, uniq: %d.\n",
 176                        req->uc_outSize, (long)nbytes, hdr.opcode, hdr.unique);
 177                 nbytes = req->uc_outSize; /* don't have more space! */
 178         }
 179         if (copy_from_user(req->uc_data, buf, nbytes)) {
 180                 req->uc_flags |= REQ_ABORT;
 181                 wake_up(&req->uc_sleep);
 182                 retval = -EFAULT;
 183                 goto out;
 184         }
 185
 186         /* adjust outsize. is this useful ?? */
 187         req->uc_outSize = nbytes;
 188         req->uc_flags |= REQ_WRITE;
 189         count = nbytes;
 190
 191         /* Convert filedescriptor into a file handle */
 192         if (req->uc_opcode == CODA_OPEN_BY_FD) {
 193                 struct coda_open_by_fd_out *outp =
 194                         (struct coda_open_by_fd_out *)req->uc_data;
 195                 if (!outp->oh.result)
 196                         outp->fh = fget(outp->fd);
 197         }
 198
 199         wake_up(&req->uc_sleep);
 200 out:
 201         return(count ? count : retval);
 202 }
 203
 204 /*
 205  *      Read a message from the kernel to Venus
 206  */
 207
 208 static ssize_t coda_psdev_read(struct file * file, char __user * buf,
 209                                size_t nbytes, loff_t *off)
 210 {
 211         DECLARE_WAITQUEUE(wait, current);
 212         struct venus_comm *vcp = (struct venus_comm *) file->private_data;
 213         struct upc_req *req;
 214         ssize_t retval = 0, count = 0;
 215
 216         if (nbytes == 0)
 217                 return 0;
 218
 219         lock_kernel();
 220
 221         add_wait_queue(&vcp->vc_waitq, &wait);
 222         set_current_state(TASK_INTERRUPTIBLE);
 223
 224         while (list_empty(&vcp->vc_pending)) {
 225                 if (file->f_flags & O_NONBLOCK) {
 226                         retval = -EAGAIN;
 227                         break;
 228                 }
 229                 if (signal_pending(current)) {
 230                         retval = -ERESTARTSYS;
 231                         break;
 232                 }
 233                 schedule();
 234         }
 235
 236         set_current_state(TASK_RUNNING);
 237         remove_wait_queue(&vcp->vc_waitq, &wait);
 238
 239         if (retval)
 240                 goto out;
 241
 242         req = list_entry(vcp->vc_pending.next, struct upc_req,uc_chain);
 243         list_del(&req->uc_chain);
 244
 245         /* Move the input args into userspace */
 246         count = req->uc_inSize;
 247         if (nbytes < req->uc_inSize) {
 248                 printk ("psdev_read: Venus read %ld bytes of %d in message\n",
 249                         (long)nbytes, req->uc_inSize);
 250                 count = nbytes;
 251         }
 252
 253         if (copy_to_user(buf, req->uc_data, count))
 254                 retval = -EFAULT;
 255
 256         /* If request was not a signal, enqueue and don't free */
 257         if (!(req->uc_flags & REQ_ASYNC)) {
 258                 req->uc_flags |= REQ_READ;
 259                 list_add_tail(&(req->uc_chain), &vcp->vc_processing);
 260                 goto out;
 261         }
 262
 263         CODA_FREE(req->uc_data, sizeof(struct coda_in_hdr));
 264         kfree(req);
 265 out:
 266         unlock_kernel();
 267         return (count ? count : retval);
 268 }
 269
 270 static int coda_psdev_open(struct inode * inode, struct file * file)
 271 {
 272         struct venus_comm *vcp;
 273         int idx, err;
 274
 275         idx = iminor(inode);
 276         if (idx < 0 || idx >= MAX_CODADEVS)
 277                 return -ENODEV;
 278
 279         lock_kernel();
 280
 281         err = -EBUSY;
 282         vcp = &coda_comms[idx];
 283         if (!vcp->vc_inuse) {
 284                 vcp->vc_inuse++;
 285
 286                 INIT_LIST_HEAD(&vcp->vc_pending);
 287                 INIT_LIST_HEAD(&vcp->vc_processing);
 288                 init_waitqueue_head(&vcp->vc_waitq);
 289                 vcp->vc_sb = NULL;
 290                 vcp->vc_seq = 0;
 291
 292                 file->private_data = vcp;
 293                 err = 0;
 294         }
 295
 296         unlock_kernel();
 297         return err;
 298 }
 299
 300
 301 static int coda_psdev_release(struct inode * inode, struct file * file)
 302 {
 303         struct venus_comm *vcp = (struct venus_comm *) file->private_data;
 304         struct upc_req *req, *tmp;
 305
 306         if (!vcp || !vcp->vc_inuse ) {
 307                 printk("psdev_release: Not open.\n");
 308                 return -1;
 309         }
 310
 311         lock_kernel();
 312
 313         /* Wakeup clients so they can return. */
 314         list_for_each_entry_safe(req, tmp, &vcp->vc_pending, uc_chain) {
 315                 list_del(&req->uc_chain);
 316
 317                 /* Async requests need to be freed here */
 318                 if (req->uc_flags & REQ_ASYNC) {
 319                         CODA_FREE(req->uc_data, sizeof(struct coda_in_hdr));
 320                         kfree(req);
 321                         continue;
 322                 }
 323                 req->uc_flags |= REQ_ABORT;
 324                 wake_up(&req->uc_sleep);
 325         }
 326
 327         list_for_each_entry_safe(req, tmp, &vcp->vc_processing, uc_chain) {
 328                 list_del(&req->uc_chain);
 329
 330                 req->uc_flags |= REQ_ABORT;
 331                 wake_up(&req->uc_sleep);
 332         }
 333
 334         file->private_data = NULL;
 335         vcp->vc_inuse--;
 336         unlock_kernel();
 337         return 0;
 338 }
 339
 340
 341 static const struct file_operations coda_psdev_fops = {
 342         .owner          = THIS_MODULE,
 343         .read           = coda_psdev_read,
 344         .write          = coda_psdev_write,
 345         .poll           = coda_psdev_poll,
 346         .ioctl          = coda_psdev_ioctl,
 347         .open           = coda_psdev_open,
 348         .release        = coda_psdev_release,
 349 };
 350
 351 static int init_coda_psdev(void)
 352 {
 353         int i, err = 0;
 354         if (register_chrdev(CODA_PSDEV_MAJOR, "coda", &coda_psdev_fops)) {
 355               printk(KERN_ERR "coda_psdev: unable to get major %d\n",
 356                      CODA_PSDEV_MAJOR);
 357               return -EIO;
 358         }
 359         coda_psdev_class = class_create(THIS_MODULE, "coda");
 360         if (IS_ERR(coda_psdev_class)) {
 361                 err = PTR_ERR(coda_psdev_class);
 362                 goto out_chrdev;
 363         }
 364         for (i = 0; i < MAX_CODADEVS; i++)
 365                 device_create(coda_psdev_class, NULL,
 366                               MKDEV(CODA_PSDEV_MAJOR, i), NULL, "cfs%d", i);
 367         coda_sysctl_init();
 368         goto out;
 369
 370 out_chrdev:
 371         unregister_chrdev(CODA_PSDEV_MAJOR, "coda");
 372 out:
 373         return err;
 374 }
 375
 376 MODULE_AUTHOR("Jan Harkes, Peter J. Braam");
 377 MODULE_DESCRIPTION("Coda Distributed File System VFS interface");
 378 MODULE_ALIAS_CHARDEV_MAJOR(CODA_PSDEV_MAJOR);
 379 MODULE_LICENSE("GPL");
 380 MODULE_VERSION("6.6");
 381
 382 static int __init init_coda(void)
 383 {
 384         int status;
 385         int i;
 386
 387         status = coda_init_inodecache();
 388         if (status)
 389                 goto out2;
 390         status = init_coda_psdev();
 391         if ( status ) {
 392                 printk("Problem (%d) in init_coda_psdev\n", status);
 393                 goto out1;
 394         }
 395
 396         status = register_filesystem(&coda_fs_type);
 397         if (status) {
 398                 printk("coda: failed to register filesystem!\n");
 399                 goto out;
 400         }
 401         return 0;
 402 out:
 403         for (i = 0; i < MAX_CODADEVS; i++)
 404                 device_destroy(coda_psdev_class, MKDEV(CODA_PSDEV_MAJOR, i));
 405         class_destroy(coda_psdev_class);
 406         unregister_chrdev(CODA_PSDEV_MAJOR, "coda");
 407         coda_sysctl_clean();
 408 out1:
 409         coda_destroy_inodecache();
 410 out2:
 411         return status;
 412 }
 413
 414 static void __exit exit_coda(void)
 415 {
 416         int err, i;
 417
 418         err = unregister_filesystem(&coda_fs_type);
 419         if ( err != 0 ) {
 420                 printk("coda: failed to unregister filesystem\n");
 421         }
 422         for (i = 0; i < MAX_CODADEVS; i++)
 423                 device_destroy(coda_psdev_class, MKDEV(CODA_PSDEV_MAJOR, i));
 424         class_destroy(coda_psdev_class);
 425         unregister_chrdev(CODA_PSDEV_MAJOR, "coda");
 426         coda_sysctl_clean();
 427         coda_destroy_inodecache();
 428 }
 429
 430 module_init(init_coda);
 431 module_exit(exit_coda);
 432