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@cymru.net>
   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/sched.h>
  25 #include <linux/lp.h>
  26 #include <linux/malloc.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/poll.h>
  35 #include <linux/init.h>
  36 #include <linux/list.h>
  37 #include <asm/io.h>
  38 #include <asm/segment.h>
  39 #include <asm/system.h>
  40 #include <asm/poll.h>
  41 #include <asm/uaccess.h>
  42
  43 #include <linux/coda.h>
  44 #include <linux/coda_linux.h>
  45 #include <linux/coda_fs_i.h>
  46 #include <linux/coda_psdev.h>
  47 #include <linux/coda_cache.h>
  48 #include <linux/coda_proc.h>
  49
  50 /*
  51  * Coda stuff
  52  */
  53 extern struct file_system_type coda_fs_type;
  54 extern int init_coda_fs(void);
  55
  56 /* statistics */
  57 int           coda_hard    = 0;  /* allows signals during upcalls */
  58 unsigned long coda_timeout = 30; /* .. secs, then signals will dequeue */
  59
  60 struct coda_sb_info coda_super_info;
  61 struct venus_comm coda_upc_comm;
  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 = &coda_upc_comm;
  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
  80 /*
  81  *      Receive a message written by Venus to the psdev
  82  */
  83
  84 static ssize_t coda_psdev_write(struct file *file, const char *buf,
  85                                 size_t count, loff_t *off)
  86 {
  87         struct venus_comm *vcp = &coda_upc_comm;
  88         struct upc_req *req = NULL;
  89         struct upc_req *tmp;
  90         struct list_head *lh;
  91         struct coda_in_hdr hdr;
  92         int error;
  93
  94
  95         if ( !coda_upc_comm.vc_pid )
  96                 return -EIO;
  97         /* Peek at the opcode, uniquefier */
  98         if (copy_from_user(&hdr, buf, 2 * sizeof(u_long)))
  99                 return -EFAULT;
 100
 101         CDEBUG(D_PSDEV, "(process,opc,uniq)=(%d,%ld,%ld), count %d\n",
 102                current->pid, hdr.opcode, hdr.unique, count);
 103
 104         if (DOWNCALL(hdr.opcode)) {
 105                 struct super_block *sb = NULL;
 106                 union outputArgs *dcbuf;
 107                 int size = sizeof(*dcbuf);
 108
 109                 sb = coda_super_info.sbi_sb;
 110                 if ( !sb ) {
 111                         printk("coda_psdev_write: downcall, no SB!\n");
 112                         return count;
 113                 }
 114                 CDEBUG(D_PSDEV, "handling downcall\n");
 115
 116                 if  ( count < sizeof(struct coda_out_hdr) ) {
 117                         printk("coda_downcall opc %ld uniq %ld, not enough!\n",
 118                                hdr.opcode, hdr.unique);
 119                         return count;
 120                 }
 121                 CODA_ALLOC(dcbuf, union outputArgs *, size);
 122                 if ( count > size ) {
 123                         printk("Coda: downcall opc %ld, uniq %ld, too much!",
 124                                hdr.opcode, hdr.unique);
 125                         count = size;
 126                 }
 127                 if (copy_from_user(dcbuf, buf, count))
 128                         return -EFAULT;
 129
 130                 /* what downcall errors does Venus handle ? */
 131                 error = coda_downcall(hdr.opcode, dcbuf, sb);
 132
 133                 if ( error) {
 134                         printk("psdev_write: coda_downcall error: %d\n",
 135                                error);
 136                         return 0;
 137                 }
 138                 CODA_FREE(dcbuf, size);
 139                 return count;
 140         }
 141
 142
 143         /* Look for the message on the processing queue. */
 144         lh  = &vcp->vc_processing;
 145         while ( (lh = lh->next) != &vcp->vc_processing ) {
 146                 tmp = list_entry(lh, struct upc_req , uc_chain);
 147                 if (tmp->uc_unique == hdr.unique) {
 148                         req = tmp;
 149                         list_del(&req->uc_chain);
 150                         CDEBUG(D_PSDEV,"Eureka: uniq %ld on queue!\n",
 151                                hdr.unique);
 152                         break;
 153                 }
 154         }
 155         if (!req) {
 156                 printk("psdev_write: msg (%ld, %ld) not found\n",
 157                        hdr.opcode, hdr.unique);
 158                 return(-ESRCH);
 159         }
 160
 161         /* move data into response buffer. */
 162         if (req->uc_outSize < count) {
 163                 printk("psdev_write: too much cnt: %d, cnt: %d, opc: %ld, uniq: %ld.\n",
 164                        req->uc_outSize, count, hdr.opcode, hdr.unique);
 165                 count = req->uc_outSize; /* don't have more space! */
 166         }
 167         if (copy_from_user(req->uc_data, buf, count))
 168                 return -EFAULT;
 169
 170         /* adjust outsize. is this usefull ?? */
 171         req->uc_outSize = count;
 172         req->uc_flags |= REQ_WRITE;
 173
 174         CDEBUG(D_PSDEV,
 175                "Found! Count %d for (opc,uniq)=(%ld,%ld), upc_req at %x\n",
 176                 count, hdr.opcode, hdr.unique, (int)&req);
 177
 178         wake_up(&req->uc_sleep);
 179         return(count);
 180 }
 181
 182 /*
 183  *      Read a message from the kernel to Venus
 184  */
 185
 186 static ssize_t coda_psdev_read(struct file * file, char * buf,
 187                                size_t count, loff_t *off)
 188 {
 189         struct venus_comm *vcp = &coda_upc_comm;
 190         struct upc_req *req;
 191         int result = count ;
 192
 193         CDEBUG(D_PSDEV, "count %d\n", count);
 194         if (list_empty(&(vcp->vc_pending))) {
 195               return -1;
 196         }
 197
 198         req = list_entry((vcp->vc_pending.next), struct upc_req, uc_chain);
 199         list_del(&(req->uc_chain));
 200
 201         /* Move the input args into userspace */
 202         if (req->uc_inSize <= count)
 203               result = req->uc_inSize;
 204
 205         if (count < req->uc_inSize) {
 206                 printk ("psdev_read: Venus read %d bytes of %d in message\n",
 207                         count, req->uc_inSize);
 208         }
 209
 210         if ( copy_to_user(buf, req->uc_data, result))
 211                 return -EFAULT;
 212
 213         /* If request was a signal, don't enqueue */
 214         if (req->uc_opcode == CODA_SIGNAL) {
 215                     CDEBUG(D_PSDEV, "vcread: signal msg (%d, %d)\n",
 216                               req->uc_opcode, req->uc_unique);
 217               CODA_FREE(req->uc_data, sizeof(struct coda_in_hdr));
 218               CODA_FREE(req, sizeof(struct upc_req));
 219               return count;
 220         }
 221
 222         req->uc_flags |= REQ_READ;
 223         list_add(&(req->uc_chain), vcp->vc_processing.prev);
 224
 225         return result;
 226 }
 227
 228
 229 static int coda_psdev_open(struct inode * inode, struct file * file)
 230 {
 231         struct venus_comm *vcp = &coda_upc_comm;
 232         ENTRY;
 233
 234         /* first opener: must be lento. Initialize & take its pid */
 235         if ( file->f_flags == O_RDWR ) {
 236                 if ( vcp->vc_pid ) {
 237                         printk("Venus pid already set to %d!!\n", vcp->vc_pid);
 238                         return -1;
 239                 }
 240                 if ( vcp->vc_inuse ) {
 241                         printk("psdev_open: Cannot O_RDWR while open.\n");
 242                         return -1;
 243                 }
 244         }
 245
 246         vcp->vc_inuse++;
 247         MOD_INC_USE_COUNT;
 248
 249
 250         if ( file->f_flags == O_RDWR ) {
 251                 vcp->vc_pid = current->pid;
 252                 vcp->vc_seq = 0;
 253                 INIT_LIST_HEAD(&vcp->vc_pending);
 254                 INIT_LIST_HEAD(&vcp->vc_processing);
 255         }
 256
 257         CDEBUG(D_PSDEV, "inuse: %d, vc_pid %d, caller %d\n",
 258                vcp->vc_inuse, vcp->vc_pid, current->pid);
 259
 260         EXIT;
 261         return 0;
 262 }
 263
 264
 265
 266 static int coda_psdev_release(struct inode * inode, struct file * file)
 267 {
 268         struct venus_comm *vcp = &coda_upc_comm;
 269         struct upc_req *req;
 270         struct list_head *lh, *next;
 271         ENTRY;
 272
 273         if ( !vcp->vc_inuse ) {
 274                 printk("psdev_release: Not open.\n");
 275                 return -1;
 276         }
 277
 278         vcp->vc_inuse--;
 279         MOD_DEC_USE_COUNT;
 280         CDEBUG(D_PSDEV, "inuse: %d, vc_pid %d, caller %d\n",
 281                vcp->vc_inuse, vcp->vc_pid, current->pid);
 282
 283         if ( vcp->vc_pid != current->pid ) {
 284                 return 0;
 285         }
 286
 287         vcp->vc_pid = 0;
 288         /* Wakeup clients so they can return. */
 289         CDEBUG(D_PSDEV, "wake up pending clients\n");
 290         lh = vcp->vc_pending.next;
 291         next = lh;
 292         while ( (lh = next) != &vcp->vc_pending) {
 293                 next = lh->next;
 294                 req = list_entry(lh, struct upc_req, uc_chain);
 295                 /* Async requests need to be freed here */
 296                 if (req->uc_flags & REQ_ASYNC) {
 297                         CODA_FREE(req->uc_data, sizeof(struct coda_in_hdr));
 298                         CODA_FREE(req, (u_int)sizeof(struct upc_req));
 299                         continue;
 300                 }
 301                 wake_up(&req->uc_sleep);
 302         }
 303
 304         lh = &vcp->vc_processing;
 305         CDEBUG(D_PSDEV, "wake up processing clients\n");
 306         while ( (lh = lh->next) != &vcp->vc_processing) {
 307                 req = list_entry(lh, struct upc_req, uc_chain);
 308                 wake_up(&req->uc_sleep);
 309         }
 310         CDEBUG(D_PSDEV, "Done.\n");
 311
 312         EXIT;
 313         return 0;
 314 }
 315
 316
 317 static struct file_operations coda_psdev_fops = {
 318       NULL,                  /* llseek */
 319       coda_psdev_read,       /* read */
 320       coda_psdev_write,      /* write */
 321       NULL,                  /* coda_psdev_readdir */
 322       coda_psdev_poll,       /* poll */
 323       NULL,                  /* ioctl */
 324       NULL,                  /* coda_psdev_mmap */
 325       coda_psdev_open,       /* open */
 326       NULL,
 327       coda_psdev_release,    /* release */
 328       NULL,                  /* fsync */
 329       NULL,                  /* fasync */
 330       NULL,                  /* check_media_change */
 331       NULL,                  /* revalidate */
 332       NULL                   /* lock */
 333 };
 334
 335
 336
 337 __initfunc(int init_coda(void))
 338 {
 339         int status;
 340         printk(KERN_INFO "Coda Kernel/Venus communications, v4.6.0, braam@cs.cmu.edu\n");
 341
 342         status = init_coda_psdev();
 343         if ( status ) {
 344                 printk("Problem (%d) in init_coda_psdev\n", status);
 345                 return status;
 346         }
 347
 348         status = init_coda_fs();
 349         if (status) {
 350                 printk("coda: failed in init_coda_fs!\n");
 351         }
 352         return status;
 353 }
 354
 355 int init_coda_psdev(void)
 356 {
 357         if(register_chrdev(CODA_PSDEV_MAJOR,"coda_psdev", &coda_psdev_fops)) {
 358               printk(KERN_ERR "coda_psdev: unable to get major %d\n",
 359                      CODA_PSDEV_MAJOR);
 360               return -EIO;
 361         }
 362         memset(&coda_upc_comm, 0, sizeof(coda_upc_comm));
 363         memset(&coda_super_info, 0, sizeof(coda_super_info));
 364
 365         coda_sysctl_init();
 366
 367         return 0;
 368 }
 369
 370
 371 #ifdef MODULE
 372
 373 MODULE_AUTHOR("Peter J. Braam <braam@cs.cmu.edu>");
 374
 375 int init_module(void)
 376 {
 377         int status;
 378         printk(KERN_INFO "Coda Kernel/Venus communications (module), v5.0-pre1, braam@cs.cmu.edu.\n");
 379
 380         status = init_coda_psdev();
 381         if ( status ) {
 382                 printk("Problem (%d) in init_coda_psdev\n", status);
 383                 return status;
 384         }
 385
 386         status = init_coda_fs();
 387         if (status) {
 388                 printk("coda: failed in init_coda_fs!\n");
 389         }
 390         return status;
 391 }
 392
 393
 394 void cleanup_module(void)
 395 {
 396         int err;
 397
 398         ENTRY;
 399
 400         if ( (err = unregister_filesystem(&coda_fs_type)) != 0 ) {
 401                 printk("coda: failed to unregister filesystem\n");
 402         }
 403         unregister_chrdev(CODA_PSDEV_MAJOR,"coda_psdev");
 404         coda_sysctl_clean();
 405 }
 406
 407 #endif
 408