release/src-rt-6.x/linux/linux-2.6/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/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 #include <linux/coda_proc.h>
  49
  50 #include "coda_int.h"
  51
  52 #define upc_free(r) kfree(r)
  53
  54 /* statistics */
  55 int           coda_hard;         /* allows signals during upcalls */
  56 unsigned long coda_timeout = 30; /* .. secs, then signals will dequeue */
  57
  58
  59 struct venus_comm coda_comms[MAX_CODADEVS];
  60 static struct class *coda_psdev_class;
  61
  62 /*
  63  * Device operations
  64  */
  65
  66 static unsigned int coda_psdev_poll(struct file *file, poll_table * wait)
  67 {
  68         struct venus_comm *vcp = (struct venus_comm *) file->private_data;
  69         unsigned int mask = POLLOUT | POLLWRNORM;
  70
  71         poll_wait(file, &vcp->vc_waitq, wait);
  72         if (!list_empty(&vcp->vc_pending))
  73                 mask |= POLLIN | POLLRDNORM;
  74
  75         return mask;
  76 }
  77
  78 static int coda_psdev_ioctl(struct inode * inode, struct file * filp,
  79                             unsigned int cmd, unsigned long arg)
  80 {
  81         unsigned int data;
  82
  83         switch(cmd) {
  84         case CIOC_KERNEL_VERSION:
  85                 data = CODA_KERNEL_VERSION;
  86                 return put_user(data, (int __user *) arg);
  87         default:
  88                 return -ENOTTY;
  89         }
  90
  91         return 0;
  92 }
  93
  94 /*
  95  *      Receive a message written by Venus to the psdev
  96  */
  97
  98 static ssize_t coda_psdev_write(struct file *file, const char __user *buf,
  99                                 size_t nbytes, loff_t *off)
 100 {
 101         struct venus_comm *vcp = (struct venus_comm *) file->private_data;
 102         struct upc_req *req = NULL;
 103         struct upc_req *tmp;
 104         struct list_head *lh;
 105         struct coda_in_hdr hdr;
 106         ssize_t retval = 0, count = 0;
 107         int error;
 108
 109         /* Peek at the opcode, uniquefier */
 110         if (copy_from_user(&hdr, buf, 2 * sizeof(u_long)))
 111                 return -EFAULT;
 112
 113         if (DOWNCALL(hdr.opcode)) {
 114                 struct super_block *sb = NULL;
 115                 union outputArgs *dcbuf;
 116                 int size = sizeof(*dcbuf);
 117
 118                 sb = vcp->vc_sb;
 119                 if ( !sb ) {
 120                         count = nbytes;
 121                         goto out;
 122                 }
 123
 124                 if  ( nbytes < sizeof(struct coda_out_hdr) ) {
 125                         printk("coda_downcall opc %d uniq %d, not enough!\n",
 126                                hdr.opcode, hdr.unique);
 127                         count = nbytes;
 128                         goto out;
 129                 }
 130                 if ( nbytes > size ) {
 131                         printk("Coda: downcall opc %d, uniq %d, too much!",
 132                                hdr.opcode, hdr.unique);
 133                         nbytes = size;
 134                 }
 135                 CODA_ALLOC(dcbuf, union outputArgs *, nbytes);
 136                 if (copy_from_user(dcbuf, buf, nbytes)) {
 137                         CODA_FREE(dcbuf, nbytes);
 138                         retval = -EFAULT;
 139                         goto out;
 140                 }
 141
 142                 /* what downcall errors does Venus handle ? */
 143                 lock_kernel();
 144                 error = coda_downcall(hdr.opcode, dcbuf, sb);
 145                 unlock_kernel();
 146
 147                 CODA_FREE(dcbuf, nbytes);
 148                 if (error) {
 149                         printk("psdev_write: coda_downcall error: %d\n", error);
 150                         retval = error;
 151                         goto out;
 152                 }
 153                 count = nbytes;
 154                 goto out;
 155         }
 156
 157         /* Look for the message on the processing queue. */
 158         lock_kernel();
 159         list_for_each(lh, &vcp->vc_processing) {
 160                 tmp = list_entry(lh, struct upc_req , uc_chain);
 161                 if (tmp->uc_unique == hdr.unique) {
 162                         req = tmp;
 163                         list_del(&req->uc_chain);
 164                         break;
 165                 }
 166         }
 167         unlock_kernel();
 168
 169         if (!req) {
 170                 printk("psdev_write: msg (%d, %d) not found\n",
 171                         hdr.opcode, hdr.unique);
 172                 retval = -ESRCH;
 173                 goto out;
 174         }
 175
 176         /* move data into response buffer. */
 177         if (req->uc_outSize < nbytes) {
 178                 printk("psdev_write: too much cnt: %d, cnt: %ld, opc: %d, uniq: %d.\n",
 179                        req->uc_outSize, (long)nbytes, hdr.opcode, hdr.unique);
 180                 nbytes = req->uc_outSize; /* don't have more space! */
 181         }
 182         if (copy_from_user(req->uc_data, buf, nbytes)) {
 183                 req->uc_flags |= REQ_ABORT;
 184                 wake_up(&req->uc_sleep);
 185                 retval = -EFAULT;
 186                 goto out;
 187         }
 188
 189         /* adjust outsize. is this useful ?? */
 190         req->uc_outSize = nbytes;
 191         req->uc_flags |= REQ_WRITE;
 192         count = nbytes;
 193
 194         /* Convert filedescriptor into a file handle */
 195         if (req->uc_opcode == CODA_OPEN_BY_FD) {
 196                 struct coda_open_by_fd_out *outp =
 197                         (struct coda_open_by_fd_out *)req->uc_data;
 198                 outp->fh = fget(outp->fd);
 199         }
 200
 201         wake_up(&req->uc_sleep);
 202 out:
 203         return(count ? count : retval);
 204 }
 205
 206 /*
 207  *      Read a message from the kernel to Venus
 208  */
 209
 210 static ssize_t coda_psdev_read(struct file * file, char __user * buf,
 211                                size_t nbytes, loff_t *off)
 212 {
 213         DECLARE_WAITQUEUE(wait, current);
 214         struct venus_comm *vcp = (struct venus_comm *) file->private_data;
 215         struct upc_req *req;
 216         ssize_t retval = 0, count = 0;
 217
 218         if (nbytes == 0)
 219                 return 0;
 220
 221         lock_kernel();
 222
 223         add_wait_queue(&vcp->vc_waitq, &wait);
 224         set_current_state(TASK_INTERRUPTIBLE);
 225
 226         while (list_empty(&vcp->vc_pending)) {
 227                 if (file->f_flags & O_NONBLOCK) {
 228                         retval = -EAGAIN;
 229                         break;
 230                 }
 231                 if (signal_pending(current)) {
 232                         retval = -ERESTARTSYS;
 233                         break;
 234                 }
 235                 schedule();
 236         }
 237
 238         set_current_state(TASK_RUNNING);
 239         remove_wait_queue(&vcp->vc_waitq, &wait);
 240
 241         if (retval)
 242                 goto out;
 243
 244         req = list_entry(vcp->vc_pending.next, struct upc_req,uc_chain);
 245         list_del(&req->uc_chain);
 246
 247         /* Move the input args into userspace */
 248         count = req->uc_inSize;
 249         if (nbytes < req->uc_inSize) {
 250                 printk ("psdev_read: Venus read %ld bytes of %d in message\n",
 251                         (long)nbytes, req->uc_inSize);
 252                 count = nbytes;
 253         }
 254
 255         if (copy_to_user(buf, req->uc_data, count))
 256                 retval = -EFAULT;
 257
 258         /* If request was not a signal, enqueue and don't free */
 259         if (!(req->uc_flags & REQ_ASYNC)) {
 260                 req->uc_flags |= REQ_READ;
 261                 list_add_tail(&(req->uc_chain), &vcp->vc_processing);
 262                 goto out;
 263         }
 264
 265         CODA_FREE(req->uc_data, sizeof(struct coda_in_hdr));
 266         upc_free(req);
 267 out:
 268         unlock_kernel();
 269         return (count ? count : retval);
 270 }
 271
 272 static int coda_psdev_open(struct inode * inode, struct file * file)
 273 {
 274         struct venus_comm *vcp;
 275         int idx;
 276
 277         lock_kernel();
 278         idx = iminor(inode);
 279         if(idx >= MAX_CODADEVS) {
 280                 unlock_kernel();
 281                 return -ENODEV;
 282         }
 283
 284         vcp = &coda_comms[idx];
 285         if(vcp->vc_inuse) {
 286                 unlock_kernel();
 287                 return -EBUSY;
 288         }
 289
 290         if (!vcp->vc_inuse++) {
 291                 INIT_LIST_HEAD(&vcp->vc_pending);
 292                 INIT_LIST_HEAD(&vcp->vc_processing);
 293                 init_waitqueue_head(&vcp->vc_waitq);
 294                 vcp->vc_sb = NULL;
 295                 vcp->vc_seq = 0;
 296         }
 297
 298         file->private_data = vcp;
 299
 300         unlock_kernel();
 301         return 0;
 302 }
 303
 304
 305 static int coda_psdev_release(struct inode * inode, struct file * file)
 306 {
 307         struct venus_comm *vcp = (struct venus_comm *) file->private_data;
 308         struct upc_req *req, *tmp;
 309
 310         lock_kernel();
 311         if ( !vcp->vc_inuse ) {
 312                 unlock_kernel();
 313                 printk("psdev_release: Not open.\n");
 314                 return -1;
 315         }
 316
 317         if (--vcp->vc_inuse) {
 318                 unlock_kernel();
 319                 return 0;
 320         }
 321
 322         /* Wakeup clients so they can return. */
 323         list_for_each_entry_safe(req, tmp, &vcp->vc_pending, uc_chain) {
 324                 /* Async requests need to be freed here */
 325                 if (req->uc_flags & REQ_ASYNC) {
 326                         CODA_FREE(req->uc_data, sizeof(struct coda_in_hdr));
 327                         upc_free(req);
 328                         continue;
 329                 }
 330                 req->uc_flags |= REQ_ABORT;
 331                 wake_up(&req->uc_sleep);
 332         }
 333
 334         list_for_each_entry(req, &vcp->vc_processing, uc_chain) {
 335                 req->uc_flags |= REQ_ABORT;
 336                 wake_up(&req->uc_sleep);
 337         }
 338
 339         unlock_kernel();
 340         return 0;
 341 }
 342
 343
 344 static const struct file_operations coda_psdev_fops = {
 345         .owner          = THIS_MODULE,
 346         .read           = coda_psdev_read,
 347         .write          = coda_psdev_write,
 348         .poll           = coda_psdev_poll,
 349         .ioctl          = coda_psdev_ioctl,
 350         .open           = coda_psdev_open,
 351         .release        = coda_psdev_release,
 352 };
 353
 354 static int init_coda_psdev(void)
 355 {
 356         int i, err = 0;
 357         if (register_chrdev(CODA_PSDEV_MAJOR, "coda", &coda_psdev_fops)) {
 358               printk(KERN_ERR "coda_psdev: unable to get major %d\n",
 359                      CODA_PSDEV_MAJOR);
 360               return -EIO;
 361         }
 362         coda_psdev_class = class_create(THIS_MODULE, "coda");
 363         if (IS_ERR(coda_psdev_class)) {
 364                 err = PTR_ERR(coda_psdev_class);
 365                 goto out_chrdev;
 366         }
 367         for (i = 0; i < MAX_CODADEVS; i++)
 368                 class_device_create(coda_psdev_class, NULL,
 369                                 MKDEV(CODA_PSDEV_MAJOR,i), NULL, "cfs%d", i);
 370         coda_sysctl_init();
 371         goto out;
 372
 373 out_chrdev:
 374         unregister_chrdev(CODA_PSDEV_MAJOR, "coda");
 375 out:
 376         return err;
 377 }
 378
 379
 380 MODULE_AUTHOR("Peter J. Braam <braam@cs.cmu.edu>");
 381 MODULE_LICENSE("GPL");
 382
 383 static int __init init_coda(void)
 384 {
 385         int status;
 386         int i;
 387         printk(KERN_INFO "Coda Kernel/Venus communications, "
 388 #ifdef CONFIG_CODA_FS_OLD_API
 389                "v5.3.20"
 390 #else
 391                "v6.0.0"
 392 #endif
 393                ", coda@cs.cmu.edu\n");
 394
 395         status = coda_init_inodecache();
 396         if (status)
 397                 goto out2;
 398         status = init_coda_psdev();
 399         if ( status ) {
 400                 printk("Problem (%d) in init_coda_psdev\n", status);
 401                 goto out1;
 402         }
 403
 404         status = register_filesystem(&coda_fs_type);
 405         if (status) {
 406                 printk("coda: failed to register filesystem!\n");
 407                 goto out;
 408         }
 409         return 0;
 410 out:
 411         for (i = 0; i < MAX_CODADEVS; i++)
 412                 class_device_destroy(coda_psdev_class, MKDEV(CODA_PSDEV_MAJOR, i));
 413         class_destroy(coda_psdev_class);
 414         unregister_chrdev(CODA_PSDEV_MAJOR, "coda");
 415         coda_sysctl_clean();
 416 out1:
 417         coda_destroy_inodecache();
 418 out2:
 419         return status;
 420 }
 421
 422 static void __exit exit_coda(void)
 423 {
 424         int err, i;
 425
 426         err = unregister_filesystem(&coda_fs_type);
 427         if ( err != 0 ) {
 428                 printk("coda: failed to unregister filesystem\n");
 429         }
 430         for (i = 0; i < MAX_CODADEVS; i++)
 431                 class_device_destroy(coda_psdev_class, MKDEV(CODA_PSDEV_MAJOR, i));
 432         class_destroy(coda_psdev_class);
 433         unregister_chrdev(CODA_PSDEV_MAJOR, "coda");
 434         coda_sysctl_clean();
 435         coda_destroy_inodecache();
 436 }
 437
 438 module_init(init_coda);
 439 module_exit(exit_coda);
 440