kernel/blk_drv/scsi/sd.c

/* */
This source file includes following definitions.
sd_open
sd_release
sd_geninit
rw_intr
do_sd_request
requeue_sd_request
check_scsidisk_media_change
sd_init_done
sd_init_onedisk
sd_init
sd_init1
sd_attach
revalidate_scsidisk
   1 /*
   2  *      sd.c Copyright (C) 1992 Drew Eckhardt 
   3  *      Linux scsi disk driver by
   4  *              Drew Eckhardt 
   5  *
   6  *      <drew@colorado.edu>
   7  *
   8  *       Modified by Eric Youngdale eric@tantalus.nrl.navy.mil to
   9  *       add scatter-gather, multiple outstanding request, and other
  10  *       enhancements.
  11  */
  12 
  13 #include <linux/fs.h>
  14 #include <linux/kernel.h>
  15 #include <linux/sched.h>
  16 #include <linux/string.h>
  17 #include <linux/errno.h>
  18 #include <asm/system.h>
  19 
  20 
  21 #define MAJOR_NR 8
  22 
  23 #include "../blk.h"
  24 #include "scsi.h"
  25 #include "hosts.h"
  26 #include "sd.h"
  27 #include "scsi_ioctl.h"
  28 
  29 #include <linux/genhd.h>
  30 
  31 /*
  32 static const char RCSid[] = "$Header:";
  33 */
  34 
  35 #define MAX_RETRIES 5
  36 
  37 /*
  38  *      Time out in seconds
  39  */
  40 
  41 #define SD_TIMEOUT 200
  42 
  43 struct hd_struct * sd;
  44 
  45 int NR_SD=0;
  46 int MAX_SD=0;
  47 Scsi_Disk * rscsi_disks;
  48 static int * sd_sizes;
  49 
  50 /* used to re-read partitions. */
  51 extern void resetup_one_dev(struct gendisk *, unsigned int);
  52 
  53 extern int sd_ioctl(struct inode *, struct file *, unsigned int, unsigned int);
  54 
  55 static sd_init_onedisk(int);
  56 
  57 static void requeue_sd_request (Scsi_Cmnd * SCpnt);
  58 
  59 static int sd_open(struct inode * inode, struct file * filp)
     /*  */
  60 {
  61         int target;
  62         target =  DEVICE_NR(MINOR(inode->i_rdev));
  63 
  64         if(target >= NR_SD || !rscsi_disks[target].device)
  65           return -ENODEV;   /* No such device */
  66         
  67 /* Make sure that only one process can do a check_change_disk at one time.
  68  This is also used to lock out further access when the partition table is being re-read. */
  69 
  70         while (rscsi_disks[target].device->busy);
  71 
  72         if(rscsi_disks[target].device->removable) {
  73           check_disk_change(inode->i_rdev);
  74 
  75           if(!rscsi_disks[target].device->access_count)
  76             sd_ioctl(inode, NULL, SCSI_IOCTL_DOORLOCK, 0);
  77         };
  78         rscsi_disks[target].device->access_count++;
  79         return 0;
  80 }
  81 
  82 static void sd_release(struct inode * inode, struct file * file)
     /*  */
  83 {
  84         int target;
  85         sync_dev(inode->i_rdev);
  86 
  87         target =  DEVICE_NR(MINOR(inode->i_rdev));
  88 
  89         rscsi_disks[target].device->access_count--;
  90 
  91         if(rscsi_disks[target].device->removable) {
  92           if(!rscsi_disks[target].device->access_count)
  93             sd_ioctl(inode, NULL, SCSI_IOCTL_DOORUNLOCK, 0);
  94         };
  95 }
  96 
  97 static struct gendisk sd_gendisk;
  98 
  99 static void sd_geninit (void) {
     /*  */
 100         int i;
 101         for (i = 0; i < NR_SD; ++i)
 102           sd[i << 4].nr_sects = rscsi_disks[i].capacity;
 103         sd_gendisk.nr_real = NR_SD;
 104 }
 105 
 106 static struct file_operations sd_fops = {
 107         NULL,                   /* lseek - default */
 108         block_read,             /* read - general block-dev read */
 109         block_write,            /* write - general block-dev write */
 110         NULL,                   /* readdir - bad */
 111         NULL,                   /* select */
 112         sd_ioctl,               /* ioctl */
 113         NULL,                   /* mmap */
 114         sd_open,                /* open code */
 115         sd_release              /* release */
 116 };
 117 
 118 static struct gendisk sd_gendisk = {
 119         MAJOR_NR,               /* Major number */
 120         "sd",           /* Major name */
 121         4,              /* Bits to shift to get real from partition */
 122         1 << 4,         /* Number of partitions per real */
 123         0,              /* maximum number of real */
 124         sd_geninit,     /* init function */
 125         NULL,           /* hd struct */
 126         NULL,   /* block sizes */
 127         0,              /* number */
 128         NULL,   /* internal */
 129         NULL            /* next */
 130 };
 131 
 132 /*
 133         rw_intr is the interrupt routine for the device driver.  It will
 134         be notified on the end of a SCSI read / write, and
 135         will take on of several actions based on success or failure.
 136 */
 137 
 138 static void rw_intr (Scsi_Cmnd *SCpnt)
     /*  */
 139 {
 140   int result = SCpnt->result;
 141   int this_count = SCpnt->bufflen >> 9;
 142 
 143 #ifdef DEBUG
 144   printk("sd%d : rw_intr(%d, %x)\n", MINOR(SCpnt->request.dev), SCpnt->host, result);
 145 #endif
 146 
 147 /*
 148   First case : we assume that the command succeeded.  One of two things will
 149   happen here.  Either we will be finished, or there will be more
 150   sectors that we were unable to read last time.
 151 */
 152 
 153   if (!result) {
 154 
 155 #ifdef DEBUG
 156     printk("sd%d : %d sectors remain.\n", MINOR(SCpnt->request.dev), SCpnt->request.nr_sectors);
 157     printk("use_sg is %d\n ",SCpnt->use_sg);
 158 #endif
 159     if (SCpnt->use_sg) {
 160       struct scatterlist * sgpnt;
 161       int i;
 162       sgpnt = (struct scatterlist *) SCpnt->buffer;
 163       for(i=0; i<SCpnt->use_sg; i++) {
 164 #ifdef DEBUG
 165         printk(":%x %x %d\n",sgpnt[i].alt_address, sgpnt[i].address, sgpnt[i].length);
 166 #endif
 167         if (sgpnt[i].alt_address) {
 168           if (SCpnt->request.cmd == READ)
 169             memcpy(sgpnt[i].alt_address, sgpnt[i].address, sgpnt[i].length);
 170           scsi_free(sgpnt[i].address, sgpnt[i].length);
 171         };
 172       };
 173       scsi_free(SCpnt->buffer, SCpnt->sglist_len);  /* Free list of scatter-gather pointers */
 174     } else {
 175       if (SCpnt->buffer != SCpnt->request.buffer) {
 176 #ifdef DEBUG
 177         printk("nosg: %x %x %d\n",SCpnt->request.buffer, SCpnt->buffer,
 178                    SCpnt->bufflen);
 179 #endif  
 180           if (SCpnt->request.cmd == READ)
 181             memcpy(SCpnt->request.buffer, SCpnt->buffer,
 182                    SCpnt->bufflen);
 183           scsi_free(SCpnt->buffer, SCpnt->bufflen);
 184       };
 185     };
 186 /*
 187  *      If multiple sectors are requested in one buffer, then
 188  *      they will have been finished off by the first command.  If
 189  *      not, then we have a multi-buffer command.
 190  */
 191     if (SCpnt->request.nr_sectors > this_count)
 192       {
 193         SCpnt->request.errors = 0;
 194         
 195         if (!SCpnt->request.bh)
 196           {
 197 #ifdef DEBUG
 198             printk("sd%d : handling page request, no buffer\n",
 199                    MINOR(SCpnt->request.dev));
 200 #endif
 201 /*
 202   The SCpnt->request.nr_sectors field is always done in 512 byte sectors,
 203   even if this really isn't the case.
 204 */
 205             printk("sd.c: linked page request. (%x %x)",
 206                   SCpnt->request.sector, this_count);
 207             panic("Aiiiiiiiiiiiieeeeeeeee");
 208           }
 209       }
 210     end_scsi_request(SCpnt, 1, this_count);
 211     requeue_sd_request(SCpnt);
 212     return;
 213   }
 214 
 215 /* Free up any indirection buffers we allocated for DMA purposes. */
 216     if (SCpnt->use_sg) {
 217       struct scatterlist * sgpnt;
 218       int i;
 219       sgpnt = (struct scatterlist *) SCpnt->buffer;
 220       for(i=0; i<SCpnt->use_sg; i++) {
 221 #ifdef DEBUG
 222         printk("err: %x %x %d\n",SCpnt->request.buffer, SCpnt->buffer,
 223                    SCpnt->bufflen);
 224 #endif
 225         if (sgpnt[i].alt_address) {
 226           scsi_free(sgpnt[i].address, sgpnt[i].length);
 227         };
 228       };
 229       scsi_free(SCpnt->buffer, SCpnt->sglist_len);  /* Free list of scatter-gather pointers */
 230     } else {
 231 #ifdef DEBUG
 232       printk("nosgerr: %x %x %d\n",SCpnt->request.buffer, SCpnt->buffer,
 233                    SCpnt->bufflen);
 234 #endif
 235       if (SCpnt->buffer != SCpnt->request.buffer)
 236         scsi_free(SCpnt->buffer, SCpnt->bufflen);
 237     };
 238 
 239 /*
 240         Now, if we were good little boys and girls, Santa left us a request
 241         sense buffer.  We can extract information from this, so we
 242         can choose a block to remap, etc.
 243 */
 244 
 245         if (driver_byte(result) != 0) {
 246           {
 247             int i;
 248             printk("Dumping sense buffer: ");
 249             for(i=0;i<10;i++) printk(" %d",SCpnt->sense_buffer[i]);
 250           };
 251           if (sugestion(result) == SUGGEST_REMAP) {
 252 #ifdef REMAP
 253 /*
 254         Not yet implemented.  A read will fail after being remapped,
 255         a write will call the strategy routine again.
 256 */
 257             if rscsi_disks[DEVICE_NR(SCpnt->request.dev)].remap
 258               {
 259                 result = 0;
 260               }
 261             else
 262               
 263 #endif
 264             }
 265 
 266           if ((SCpnt->sense_buffer[0] & 0x7f) == 0x70) {
 267             if ((SCpnt->sense_buffer[2] & 0xf) == UNIT_ATTENTION) {
 268               /* detected disc change.  set a bit and quietly refuse    */
 269               /* further access.                                        */
 270               
 271               rscsi_disks[DEVICE_NR(SCpnt->request.dev)].device->changed = 1;
 272               end_scsi_request(SCpnt, 0, this_count);
 273               requeue_sd_request(SCpnt);
 274               return;
 275             }
 276           }
 277           
 278 
 279 /*      If we had an ILLEGAL REQUEST returned, then we may have
 280 performed an unsupported command.  The only thing this should be would
 281 be a ten byte read where only a six byte read was supportted.  Also,
 282 on a system where READ CAPACITY failed, we mave have read past the end
 283 of the  disk. 
 284 */
 285 
 286           if (SCpnt->sense_buffer[2] == ILLEGAL_REQUEST) {
 287             if (rscsi_disks[DEVICE_NR(SCpnt->request.dev)].ten) {
 288               rscsi_disks[DEVICE_NR(SCpnt->request.dev)].ten = 0;
 289               requeue_sd_request(SCpnt);
 290               result = 0;
 291             } else {
 292             }
 293           }
 294         }  /* driver byte != 0 */
 295         if (result) {
 296                 printk("SCSI disk error : host %d id %d lun %d return code = %x\n",
 297                        rscsi_disks[DEVICE_NR(SCpnt->request.dev)].device->host_no,
 298                        rscsi_disks[DEVICE_NR(SCpnt->request.dev)].device->id,
 299                        rscsi_disks[DEVICE_NR(SCpnt->request.dev)].device->lun, result);
 300 
 301                 if (driver_byte(result) & DRIVER_SENSE)
 302                         printk("\tSense class %x, sense error %x, extended sense %x\n",
 303                                 sense_class(SCpnt->sense_buffer[0]),
 304                                 sense_error(SCpnt->sense_buffer[0]),
 305                                 SCpnt->sense_buffer[2] & 0xf);
 306 
 307                 end_scsi_request(SCpnt, 0, SCpnt->request.current_nr_sectors);
 308                 requeue_sd_request(SCpnt);
 309                 return;
 310         }
 311 }
 312 
 313 /*
 314         requeue_sd_request() is the request handler function for the sd driver.
 315         Its function in life is to take block device requests, and translate
 316         them to SCSI commands.
 317 */
 318 
 319 static void do_sd_request (void)
     /*  */
 320 {
 321   Scsi_Cmnd * SCpnt = NULL;
 322   struct request * req = NULL;
 323   int flag = 0;
 324   while (1==1){
 325     cli();
 326     if (CURRENT != NULL && CURRENT->dev == -1) {
 327       sti();
 328       return;
 329     };
 330 
 331     INIT_SCSI_REQUEST;
 332 
 333 /* We have to be careful here.  allocate_device will get a free pointer, but
 334    there is no guarantee that it is queueable.  In normal usage, we want to
 335    call this, because other types of devices may have the host all tied up,
 336    and we want to make sure that we have at least one request pending for this
 337    type of device.   We can also come through here while servicing an
 338    interrupt, because of the need to start another command.  If we call
 339    allocate_device more than once, then the system can wedge if the command
 340    is not queueable.  The request_queueable function is safe because it checks
 341    to make sure that the host is able to take another command before it returns
 342    a pointer.  */
 343 
 344     if (flag++ == 0)
 345       SCpnt = allocate_device(&CURRENT,
 346                               rscsi_disks[DEVICE_NR(MINOR(CURRENT->dev))].device->index, 0); 
 347     else SCpnt = NULL;
 348     sti();
 349 
 350 /* This is a performance enhancement.  We dig down into the request list and
 351    try and find a queueable request (i.e. device not busy, and host able to
 352    accept another command.  If we find one, then we queue it. This can
 353    make a big difference on systems with more than one disk drive.  We want
 354    to have the interrupts off when monkeying with the request list, because
 355    otherwise the kernel might try and slip in a request inbetween somewhere. */
 356 
 357     if (!SCpnt && NR_SD > 1){
 358       struct request *req1;
 359       req1 = NULL;
 360       cli();
 361       req = CURRENT;
 362       while(req){
 363         SCpnt = request_queueable(req,
 364                                   rscsi_disks[DEVICE_NR(MINOR(req->dev))].device->index);
 365         if(SCpnt) break;
 366         req1 = req;
 367         req = req->next;
 368       };
 369       if (SCpnt) {
 370         if (req == CURRENT) 
 371           CURRENT = CURRENT->next;
 372         else
 373           req1->next = req->next;
 374       };
 375       sti();
 376     };
 377     
 378     if (!SCpnt) return; /* Could not find anything to do */
 379     
 380     wake_up(&wait_for_request);
 381     
 382     /* Queue command */
 383     requeue_sd_request(SCpnt);
 384   };  /* While */
 385 }    
 386 
 387 static void requeue_sd_request (Scsi_Cmnd * SCpnt)
     /*  */
 388 {
 389         int dev, block, this_count;
 390         unsigned char cmd[10];
 391         char * buff;
 392 
 393 repeat:
 394 
 395         if(SCpnt->request.dev <= 0)
 396           return do_sd_request();
 397 
 398         dev =  MINOR(SCpnt->request.dev);
 399         block = SCpnt->request.sector;
 400         this_count = 0;
 401 
 402 #ifdef DEBUG
 403         printk("Doing sd request, dev = %d, block = %d\n", dev, block);
 404 #endif
 405 
 406         if (dev >= (NR_SD << 4) || block + SCpnt->request.nr_sectors > sd[dev].nr_sects)
 407                 {
 408                 end_scsi_request(SCpnt, 0, SCpnt->request.nr_sectors);
 409                 goto repeat;
 410                 }
 411 
 412         block += sd[dev].start_sect;
 413         dev = DEVICE_NR(dev);
 414 
 415         if (rscsi_disks[dev].device->changed)
 416                 {
 417 /*
 418  * quietly refuse to do anything to a changed disc until the changed bit has been reset
 419  */
 420                 /* printk("SCSI disk has been changed.  Prohibiting further I/O.\n");   */
 421                 end_scsi_request(SCpnt, 0, SCpnt->request.nr_sectors);
 422                 goto repeat;
 423                 }
 424 
 425 #ifdef DEBUG
 426         printk("sd%d : real dev = /dev/sd%d, block = %d\n", MINOR(SCpnt->request.dev), dev, block);
 427 #endif
 428 
 429         switch (SCpnt->request.cmd)
 430                 {
 431                 case WRITE :
 432                         if (!rscsi_disks[dev].device->writeable)
 433                                 {
 434                                 end_scsi_request(SCpnt, 0, SCpnt->request.nr_sectors);
 435                                 goto repeat;
 436                                 }
 437                         cmd[0] = WRITE_6;
 438                         break;
 439                 case READ :
 440                         cmd[0] = READ_6;
 441                         break;
 442                 default :
 443                         printk ("Unknown sd command %d\n", SCpnt->request.cmd);
 444                         panic("");
 445                       }
 446 
 447         SCpnt->this_count = 0;
 448 
 449         if (!SCpnt->request.bh || 
 450             (SCpnt->request.nr_sectors == SCpnt->request.current_nr_sectors)) {
 451 
 452           /* case of page request (i.e. raw device), or unlinked buffer */
 453           this_count = SCpnt->request.nr_sectors;
 454           buff = SCpnt->request.buffer;
 455           SCpnt->use_sg = 0;
 456 
 457         } else if (scsi_hosts[SCpnt->host].sg_tablesize == 0 ||
 458                    (need_isa_buffer && 
 459                     dma_free_sectors < 10)) {
 460 
 461           /* Case of host adapter that cannot scatter-gather.  We also
 462            come here if we are running low on DMA buffer memory.  We set
 463            a threshold higher than that we would need for this request so
 464            we leave room for other requests.  Even though we would not need
 465            it all, we need to be conservative, because if we run low enough
 466            we have no choice but to panic. */
 467 
 468           if (scsi_hosts[SCpnt->host].sg_tablesize != 0 &&
 469               need_isa_buffer && 
 470               dma_free_sectors < 10)
 471             printk("Warning: SCSI DMA buffer space running low.  Using non scatter-gather I/O.\n");
 472 
 473           this_count = SCpnt->request.current_nr_sectors;
 474           buff = SCpnt->request.buffer;
 475           SCpnt->use_sg = 0;
 476 
 477         } else {
 478 
 479           /* Scatter-gather capable host adapter */
 480           struct buffer_head * bh;
 481           struct scatterlist * sgpnt;
 482           int count, this_count_max;
 483           bh = SCpnt->request.bh;
 484           this_count = 0;
 485           this_count_max = (rscsi_disks[dev].ten ? 0xffff : 0xff);
 486           count = 0;
 487           while(bh && count < scsi_hosts[SCpnt->host].sg_tablesize) {
 488             if ((this_count + (bh->b_size >> 9)) > this_count_max) break;
 489             this_count += (bh->b_size >> 9);
 490             count++;
 491             bh = bh->b_reqnext;
 492           };
 493           SCpnt->use_sg = count;  /* Number of chains */
 494           count = 512;/* scsi_malloc can only allocate in chunks of 512 bytes*/
 495           while( count < (SCpnt->use_sg * sizeof(struct scatterlist))) 
 496             count = count << 1;
 497           SCpnt->sglist_len = count;
 498           sgpnt = (struct scatterlist * ) scsi_malloc(count);
 499           if (!sgpnt) {
 500             printk("Warning - running *really* short on DMA buffers\n");
 501             SCpnt->use_sg = 0;  /* No memory left - bail out */
 502             this_count = SCpnt->request.current_nr_sectors;
 503             buff = SCpnt->request.buffer;
 504           } else {
 505             buff = (char *) sgpnt;
 506             count = 0;
 507             bh = SCpnt->request.bh;
 508             for(count = 0, bh = SCpnt->request.bh; count < SCpnt->use_sg; 
 509                 count++, bh = bh->b_reqnext) {
 510               sgpnt[count].address = bh->b_data;
 511               sgpnt[count].alt_address = NULL;
 512               sgpnt[count].length = bh->b_size;
 513               if (((int) sgpnt[count].address) + sgpnt[count].length > 
 514                   ISA_DMA_THRESHOLD & (scsi_hosts[SCpnt->host].unchecked_isa_dma)) {
 515                 sgpnt[count].alt_address = sgpnt[count].address;
 516                 /* We try and avoid exhausting the DMA pool, since it is easier
 517                    to control usage here.  In other places we might have a more
 518                    pressing need, and we would be screwed if we ran out */
 519                 if(dma_free_sectors < (bh->b_size >> 9) + 5) {
 520                   sgpnt[count].address = NULL;
 521                 } else {
 522                   sgpnt[count].address = scsi_malloc(sgpnt[count].length);
 523                 };
 524 /* If we start running low on DMA buffers, we abort the scatter-gather
 525    operation, and free all of the memory we have allocated.  We want to
 526    ensure that all scsi operations are able to do at least a non-scatter/gather
 527    operation */
 528                 if(sgpnt[count].address == NULL){ /* Out of dma memory */
 529                   printk("Warning: Running low on SCSI DMA buffers");
 530                   /* Try switching back to a non scatter-gather operation. */
 531                   while(--count){
 532                     if(sgpnt[count].alt_address) 
 533                       scsi_free(sgpnt[count].address, sgpnt[count].length);
 534                   };
 535                   this_count = SCpnt->request.current_nr_sectors;
 536                   buff = SCpnt->request.buffer;
 537                   SCpnt->use_sg = 0;
 538                   scsi_free(buff, SCpnt->sglist_len);
 539                   break;
 540                 };
 541 
 542                 if (SCpnt->request.cmd == WRITE)
 543                   memcpy(sgpnt[count].address, sgpnt[count].alt_address, 
 544                          sgpnt[count].length);
 545               };
 546             }; /* for loop */
 547           };  /* Able to malloc sgpnt */
 548         };  /* Host adapter capable of scatter-gather */
 549 
 550 /* Now handle the possibility of DMA to addresses > 16Mb */
 551 
 552         if(SCpnt->use_sg == 0){
 553           if (((int) buff) + (this_count << 9) > ISA_DMA_THRESHOLD && 
 554             (scsi_hosts[SCpnt->host].unchecked_isa_dma)) {
 555             buff = scsi_malloc(this_count << 9);
 556             if(buff == NULL) panic("Ran out of DMA buffers.");
 557             if (SCpnt->request.cmd == WRITE)
 558               memcpy(buff, (char *)SCpnt->request.buffer, this_count << 9);
 559           };
 560         };
 561 
 562 #ifdef DEBUG
 563         printk("sd%d : %s %d/%d 512 byte blocks.\n", MINOR(SCpnt->request.dev),
 564                 (SCpnt->request.cmd == WRITE) ? "writing" : "reading",
 565                 this_count, SCpnt->request.nr_sectors);
 566 #endif
 567 
 568         cmd[1] = (SCpnt->lun << 5) & 0xe0;
 569 
 570         if (rscsi_disks[dev].sector_size == 1024){
 571           if(block & 1) panic("sd.c:Bad block number requested");
 572           if(this_count & 1) panic("sd.c:Bad block number requested");
 573           block = block >> 1;
 574           this_count = this_count >> 1;
 575         };
 576 
 577         if (rscsi_disks[dev].sector_size == 256){
 578           block = block << 1;
 579           this_count = this_count << 1;
 580         };
 581 
 582         if (((this_count > 0xff) ||  (block > 0x1fffff)) && rscsi_disks[dev].ten)
 583                 {
 584                 if (this_count > 0xffff)
 585                         this_count = 0xffff;
 586 
 587                 cmd[0] += READ_10 - READ_6 ;
 588                 cmd[2] = (unsigned char) (block >> 24) & 0xff;
 589                 cmd[3] = (unsigned char) (block >> 16) & 0xff;
 590                 cmd[4] = (unsigned char) (block >> 8) & 0xff;
 591                 cmd[5] = (unsigned char) block & 0xff;
 592                 cmd[6] = cmd[9] = 0;
 593                 cmd[7] = (unsigned char) (this_count >> 8) & 0xff;
 594                 cmd[8] = (unsigned char) this_count & 0xff;
 595                 }
 596         else
 597                 {
 598                 if (this_count > 0xff)
 599                         this_count = 0xff;
 600 
 601                 cmd[1] |= (unsigned char) ((block >> 16) & 0x1f);
 602                 cmd[2] = (unsigned char) ((block >> 8) & 0xff);
 603                 cmd[3] = (unsigned char) block & 0xff;
 604                 cmd[4] = (unsigned char) this_count;
 605                 cmd[5] = 0;
 606                 }
 607 
 608         scsi_do_cmd (SCpnt, (void *) cmd, buff, 
 609                      this_count * rscsi_disks[dev].sector_size,
 610                      rw_intr, SD_TIMEOUT, MAX_RETRIES);
 611 }
 612 
 613 int check_scsidisk_media_change(int full_dev, int flag){
     /*  */
 614         int retval;
 615         int target;
 616         struct inode inode;
 617 
 618         target =  DEVICE_NR(MINOR(full_dev));
 619 
 620         if (target >= NR_SD) {
 621                 printk("SCSI disk request error: invalid device.\n");
 622                 return 0;
 623         };
 624 
 625         if(!rscsi_disks[target].device->removable) return 0;
 626 
 627         inode.i_rdev = full_dev;  /* This is all we really need here */
 628         retval = sd_ioctl(&inode, NULL, SCSI_IOCTL_TEST_UNIT_READY, 0);
 629 
 630         if(retval){ /* Unable to test, unit probably not ready.  This usually
 631                      means there is no disc in the drive.  Mark as changed,
 632                      and we will figure it out later once the drive is
 633                      available again.  */
 634 
 635           rscsi_disks[target].device->changed = 1;
 636           return 1; /* This will force a flush, if called from
 637                        check_disk_change */
 638         };
 639 
 640         retval = rscsi_disks[target].device->changed;
 641         if(!flag) rscsi_disks[target].device->changed = 0;
 642         return retval;
 643 }
 644 
 645 static void sd_init_done (Scsi_Cmnd * SCpnt)
     /*  */
 646 {
 647   struct request * req;
 648   struct task_struct * p;
 649   
 650   req = &SCpnt->request;
 651   req->dev = 0xfffe; /* Busy, but indicate request done */
 652   
 653   if ((p = req->waiting) != NULL) {
 654     req->waiting = NULL;
 655     p->state = TASK_RUNNING;
 656     if (p->counter > current->counter)
 657       need_resched = 1;
 658   }
 659 }
 660 
 661 static int sd_init_onedisk(int i)
     /*  */
 662 {
 663   int j = 0;
 664   unsigned char cmd[10];
 665   unsigned char buffer[513];
 666   int the_result, retries;
 667   Scsi_Cmnd * SCpnt;
 668 
 669   /* We need to retry the READ_CAPACITY because a UNIT_ATTENTION is considered
 670      a fatal error, and many devices report such an error just after a scsi
 671      bus reset. */
 672 
 673   SCpnt = allocate_device(NULL, rscsi_disks[i].device->index, 1);
 674 
 675   retries = 3;
 676   do {
 677     cmd[0] = READ_CAPACITY;
 678     cmd[1] = (rscsi_disks[i].device->lun << 5) & 0xe0;
 679     memset ((void *) &cmd[2], 0, 8);
 680     SCpnt->request.dev = 0xffff;  /* Mark as really busy again */
 681     SCpnt->sense_buffer[0] = 0;
 682     SCpnt->sense_buffer[2] = 0;
 683     
 684     scsi_do_cmd (SCpnt,
 685                  (void *) cmd, (void *) buffer,
 686                  512, sd_init_done,  SD_TIMEOUT,
 687                  MAX_RETRIES);
 688     
 689     if (current == task[0])
 690       while(SCpnt->request.dev != 0xfffe);
 691     else
 692       if (SCpnt->request.dev != 0xfffe){
 693         SCpnt->request.waiting = current;
 694         current->state = TASK_UNINTERRUPTIBLE;
 695         while (SCpnt->request.dev != 0xfffe) schedule();
 696       };
 697     
 698     the_result = SCpnt->result;
 699     retries--;
 700 
 701   } while(the_result && retries);
 702 
 703   SCpnt->request.dev = -1;  /* Mark as not busy */
 704 
 705   wake_up(&scsi_devices[SCpnt->index].device_wait); 
 706 
 707   /* Wake up a process waiting for device*/
 708 
 709   /*
 710    *    The SCSI standard says "READ CAPACITY is necessary for self confuring software"
 711    *    While not mandatory, support of READ CAPACITY is strongly encouraged.
 712    *    We used to die if we couldn't successfully do a READ CAPACITY.
 713    *    But, now we go on about our way.  The side effects of this are
 714    *
 715    *    1.  We can't know block size with certainty.  I have said "512 bytes is it"
 716    *            as this is most common.
 717    *
 718    *    2.  Recovery from when some one attempts to read past the end of the raw device will
 719    *        be slower.
 720    */
 721 
 722   if (the_result)
 723     {
 724       printk ("sd%d : READ CAPACITY failed.\n"
 725               "sd%d : status = %x, message = %02x, host = %02x, driver = %02x \n",
 726               i,i,
 727               rscsi_disks[i].device->host_no, rscsi_disks[i].device->id,
 728               rscsi_disks[i].device->lun,
 729               status_byte(the_result),
 730               msg_byte(the_result),
 731               host_byte(the_result),
 732               driver_byte(the_result)
 733               );
 734       if (driver_byte(the_result)  & DRIVER_SENSE)
 735         printk("sd%d : extended sense code = %1x \n", i, SCpnt->sense_buffer[2] & 0xf);
 736       else
 737         printk("sd%d : sense not available. \n", i);
 738 
 739       printk("sd%d : block size assumed to be 512 bytes, disk size 1GB.  \n", i);
 740       rscsi_disks[i].capacity = 0x1fffff;
 741       rscsi_disks[i].sector_size = 512;
 742 
 743       /* Set dirty bit for removable devices if not ready - sometimes drives
 744          will not report this properly. */
 745       if(rscsi_disks[i].device->removable && 
 746          SCpnt->sense_buffer[2] == NOT_READY)
 747         rscsi_disks[i].device->changed = 1;
 748 
 749     }
 750   else
 751     {
 752       rscsi_disks[i].capacity = (buffer[0] << 24) |
 753         (buffer[1] << 16) |
 754           (buffer[2] << 8) |
 755             buffer[3];
 756 
 757       rscsi_disks[i].sector_size = (buffer[4] << 24) |
 758         (buffer[5] << 16) | (buffer[6] << 8) | buffer[7];
 759 
 760       if (rscsi_disks[i].sector_size != 512 &&
 761           rscsi_disks[i].sector_size != 1024 &&
 762           rscsi_disks[i].sector_size != 256)
 763         {
 764           printk ("sd%d : unsupported sector size %d.\n",
 765                   i, rscsi_disks[i].sector_size);
 766           if(rscsi_disks[i].device->removable){
 767             rscsi_disks[i].capacity = 0;
 768           } else {
 769             printk ("scsi : deleting disk entry.\n");
 770             for  (j=i;  j < NR_SD - 1;)
 771               rscsi_disks[j] = rscsi_disks[++j];
 772             --i;
 773             --NR_SD;
 774             return i;
 775           };
 776         }
 777       if(rscsi_disks[i].sector_size == 1024)
 778         rscsi_disks[i].capacity <<= 1;  /* Change this into 512 byte sectors */
 779       if(rscsi_disks[i].sector_size == 256)
 780         rscsi_disks[i].capacity >>= 1;  /* Change this into 512 byte sectors */
 781     }
 782 
 783   rscsi_disks[i].ten = 1;
 784   rscsi_disks[i].remap = 1;
 785   return i;
 786 }
 787 
 788 /*
 789         The sd_init() function looks at all SCSI drives present, determines
 790         their size, and reads partition table entries for them.
 791 */
 792 
 793 unsigned long sd_init(unsigned long memory_start, unsigned long memory_end)
     /*  */
 794 {
 795         int i;
 796 
 797         if (register_blkdev(MAJOR_NR,"sd",&sd_fops)) {
 798                 printk("Unable to get major %d for SCSI disk\n",MAJOR_NR);
 799                 return memory_start;
 800         }
 801         if (MAX_SD == 0) return memory_start;
 802 
 803         sd_sizes = (int *) memory_start;
 804         memory_start += (MAX_SD << 4) * sizeof(int);
 805         memset(sd_sizes, 0, (MAX_SD << 4) * sizeof(int));
 806 
 807         sd = (struct hd_struct *) memory_start;
 808         memory_start += (MAX_SD << 4) * sizeof(struct hd_struct);
 809 
 810         sd_gendisk.max_nr = MAX_SD;
 811         sd_gendisk.part = sd;
 812         sd_gendisk.sizes = sd_sizes;
 813         sd_gendisk.real_devices = (void *) rscsi_disks;
 814 
 815         for (i = 0; i < NR_SD; ++i)
 816           i = sd_init_onedisk(i);
 817 
 818         blk_dev[MAJOR_NR].request_fn = DEVICE_REQUEST;
 819 
 820         /* If our host adapter is capable of scatter-gather, then we increase
 821            the read-ahead to 8 blocks (16 sectors).  If not, we use
 822            a two block (4 sector) read ahead. */
 823         if(scsi_hosts[rscsi_disks[0].device->host_no].sg_tablesize)
 824           read_ahead[MAJOR_NR] = 16;  /* 16 sector read-ahead */
 825         else
 826           read_ahead[MAJOR_NR] = 4;  /* 4 sector read-ahead */
 827         
 828         sd_gendisk.next = gendisk_head;
 829         gendisk_head = &sd_gendisk;
 830         return memory_start;
 831 }
 832 
 833 unsigned long sd_init1(unsigned long mem_start, unsigned long mem_end){
     /*  */
 834   rscsi_disks = (Scsi_Disk *) mem_start;
 835   mem_start += MAX_SD * sizeof(Scsi_Disk);
 836   return mem_start;
 837 };
 838 
 839 void sd_attach(Scsi_Device * SDp){
     /*  */
 840   rscsi_disks[NR_SD++].device = SDp;
 841   if(NR_SD > MAX_SD) panic ("scsi_devices corrupt (sd)");
 842 };
 843 
 844 #define DEVICE_BUSY rscsi_disks[target].device->busy
 845 #define USAGE rscsi_disks[target].device->access_count
 846 #define CAPACITY rscsi_disks[target].capacity
 847 #define MAYBE_REINIT  sd_init_onedisk(target)
 848 #define GENDISK_STRUCT sd_gendisk
 849 
 850 /* This routine is called to flush all partitions and partition tables
 851    for a changed scsi disk, and then re-read the new partition table.
 852    If we are revalidating a disk because of a media change, then we
 853    enter with usage == 0.  If we are using an ioctl, we automatically have
 854    usage == 1 (we need an open channel to use an ioctl :-), so this
 855    is our limit.
 856  */
 857 int revalidate_scsidisk(int dev, int maxusage){
     /*  */
 858           int target, major;
 859           struct gendisk * gdev;
 860           int max_p;
 861           int start;
 862           int i;
 863 
 864           target =  DEVICE_NR(MINOR(dev));
 865           gdev = &GENDISK_STRUCT;
 866 
 867           cli();
 868           if (DEVICE_BUSY || USAGE > maxusage) {
 869             sti();
 870             printk("Device busy for revalidation (usage=%d)\n", USAGE);
 871             return -EBUSY;
 872           };
 873           DEVICE_BUSY = 1;
 874           sti();
 875 
 876           max_p = gdev->max_p;
 877           start = target << gdev->minor_shift;
 878           major = MAJOR_NR << 8;
 879 
 880           for (i=max_p - 1; i >=0 ; i--) {
 881             sync_dev(major | start | i);
 882             invalidate_inodes(major | start | i);
 883             invalidate_buffers(major | start | i);
 884             gdev->part[start+i].start_sect = 0;
 885             gdev->part[start+i].nr_sects = 0;
 886           };
 887 
 888 #ifdef MAYBE_REINIT
 889           MAYBE_REINIT;
 890 #endif
 891 
 892           gdev->part[start].nr_sects = CAPACITY;
 893           resetup_one_dev(gdev, target);
 894 
 895           DEVICE_BUSY = 0;
 896           return 0;
 897 }
/* */
root/kernel/blk_drv/scsi/sd.c

DEFINITIONS
