transfer = (STp->buffer)->buffer_bytes < count - total ?	  (STp->buffer)->buffer_bytes : count - total;	memcpy_tofs(buf, (STp->buffer)->b_data +		    (STp->buffer)->read_pointer,transfer);	filp->f_pos += transfer;	buf += transfer;	total += transfer;	(STp->buffer)->buffer_bytes -= transfer;	(STp->buffer)->read_pointer += transfer;      }      else if (STp->eof != ST_NOEOF) {	STp->eof_hit = 1;	SCpnt->request.dev = -1;  /* Mark as not busy */	if (total == 0 && STp->eof == ST_FM)	  STp->eof = 0;	if (total == 0 && STp->eof == ST_EOM_OK)	  return (-EIO);  /* ST_EOM_ERROR not used in read */	return total;      }      if (STp->block_size == 0)	count = total;  /* Read only one variable length block */    } /* for (total = 0; total < count; ) */    SCpnt->request.dev = -1;  /* Mark as not busy */    return total;}/* Internal ioctl function */	static intst_int_ioctl(struct inode * inode,struct file * file,	     unsigned int cmd_in, unsigned long arg){   int dev = MINOR(inode->i_rdev);   int timeout = ST_LONG_TIMEOUT;   long ltmp;   int ioctl_result;   unsigned char cmd[10];   Scsi_Cmnd * SCpnt;   Scsi_Tape * STp;   dev = dev & 127;   STp = &(scsi_tapes[dev]);   memset(cmd, 0, 10);   switch (cmd_in) {     case MTFSF:     case MTFSFM:       cmd[0] = SPACE;       cmd[1] = 0x01; /* Space FileMarks */       cmd[2] = (arg >> 16);       cmd[3] = (arg >> 8);       cmd[4] = arg;#ifdef DEBUG       printk("st%d: Spacing tape forward over %d filemarks.\n", dev,	      cmd[2] * 65536 + cmd[3] * 256 + cmd[4]);#endif       break;      case MTBSF:     case MTBSFM:       cmd[0] = SPACE;       cmd[1] = 0x01; /* Space FileMarks */       ltmp = (-arg);       cmd[2] = (ltmp >> 16);       cmd[3] = (ltmp >> 8);       cmd[4] = ltmp;#ifdef DEBUG       if (cmd[2] & 0x80)	 ltmp = 0xff000000;       ltmp = ltmp | (cmd[2] << 16) | (cmd[3] << 8) | cmd[4];       printk("st%d: Spacing tape backward over %d filemarks.\n", dev, (-ltmp));#endif       break;       case MTFSR:       cmd[0] = SPACE;       cmd[1] = 0x00; /* Space Blocks */       cmd[2] = (arg >> 16);       cmd[3] = (arg >> 8);       cmd[4] = arg;#ifdef DEBUG       printk("st%d: Spacing tape forward %d blocks.\n", dev,	      cmd[2] * 65536 + cmd[3] * 256 + cmd[4]);#endif       break;      case MTBSR:       cmd[0] = SPACE;       cmd[1] = 0x00; /* Space Blocks */       ltmp = (-arg);       cmd[2] = (ltmp >> 16);       cmd[3] = (ltmp >> 8);       cmd[4] = ltmp;#ifdef DEBUG       if (cmd[2] & 0x80)	 ltmp = 0xff000000;       ltmp = ltmp | (cmd[2] << 16) | (cmd[3] << 8) | cmd[4];       printk("st%d: Spacing tape backward %d blocks.\n", dev, (-ltmp));#endif       break;      case MTWEOF:       if (STp->write_prot)	 return (-EACCES);       cmd[0] = WRITE_FILEMARKS;       cmd[2] = (arg >> 16);       cmd[3] = (arg >> 8);       cmd[4] = arg;       timeout = ST_TIMEOUT;#ifdef DEBUG       printk("st%d: Writing %d filemarks.\n", dev,	      cmd[2] * 65536 + cmd[3] * 256 + cmd[4]);#endif       break;      case MTREW:       cmd[0] = REZERO_UNIT;#ifdef ST_NOWAIT       cmd[1] = 1;  /* Don't wait for completion */       timeout = ST_TIMEOUT;#endif#ifdef DEBUG       printk("st%d: Rewinding tape.\n", dev);#endif       break;      case MTOFFL:       cmd[0] = START_STOP;#ifdef ST_NOWAIT       cmd[1] = 1;  /* Don't wait for completion */       timeout = ST_TIMEOUT;#endif#ifdef DEBUG       printk("st%d: Unloading tape.\n", dev);#endif       break;      case MTNOP:#ifdef DEBUG       printk("st%d: No op on tape.\n", dev);#endif       return 0;  /* Should do something ? */       break;     case MTRETEN:       cmd[0] = START_STOP;#ifdef ST_NOWAIT       cmd[1] = 1;  /* Don't wait for completion */       timeout = ST_TIMEOUT;#endif       cmd[4] = 3;#ifdef DEBUG       printk("st%d: Retensioning tape.\n", dev);#endif       break;      case MTEOM:       cmd[0] = SPACE;       cmd[1] = 3;#ifdef DEBUG       printk("st%d: Spacing to end of recorded medium.\n", dev);#endif       break;      case MTERASE:       if (STp->write_prot)	 return (-EACCES);       cmd[0] = ERASE;       cmd[1] = 1;  /* To the end of tape */#ifdef DEBUG       printk("st%d: Erasing tape.\n", dev);#endif       break;     case MTSEEK:       if ((STp->device)->scsi_level < SCSI_2) {	 cmd[0] = QFA_SEEK_BLOCK;	 cmd[2] = (arg >> 16);	 cmd[3] = (arg >> 8);	 cmd[4] = arg;	 cmd[5] = 0;       }       else {	 cmd[0] = SEEK_10;	 cmd[1] = 4;	 cmd[3] = (arg >> 24);	 cmd[4] = (arg >> 16);	 cmd[5] = (arg >> 8);	 cmd[6] = arg;       }#ifdef ST_NOWAIT       cmd[1] |= 1;  /* Don't wait for completion */       timeout = ST_TIMEOUT;#endif#ifdef DEBUG       printk("st%d: Seeking tape to block %d.\n", dev, arg);#endif       break;     case MTSETBLK:  /* Set block length */     case MTSETDENSITY: /* Set tape density */     case MTSETDRVBUFFER: /* Set drive buffering */       if (STp->dirty || (STp->buffer)->buffer_bytes != 0)	 return (-EIO);   /* Not allowed if data in buffer */       if (cmd_in == MTSETBLK &&	   arg != 0 &&	   (arg < STp->min_block || arg > STp->max_block ||	    arg > ST_BUFFER_SIZE)) {	 printk("st%d: Illegal block size.\n", dev);	 return (-EINVAL);       }       cmd[0] = MODE_SELECT;       cmd[4] = 12;       memset((STp->buffer)->b_data, 0, 12);       if (cmd_in == MTSETDRVBUFFER)	 (STp->buffer)->b_data[2] = (arg & 7) << 4;       else	 (STp->buffer)->b_data[2] = 	   STp->drv_buffer << 4;       (STp->buffer)->b_data[3] = 8;     /* block descriptor length */       if (cmd_in == MTSETDENSITY)	 (STp->buffer)->b_data[4] = arg;       else	 (STp->buffer)->b_data[4] = STp->density;       if (cmd_in == MTSETBLK)	 ltmp = arg;       else	 ltmp = STp->block_size;       (STp->buffer)->b_data[9] = (ltmp >> 16);       (STp->buffer)->b_data[10] = (ltmp >> 8);       (STp->buffer)->b_data[11] = ltmp;       timeout = ST_TIMEOUT;#ifdef DEBUG       if (cmd_in == MTSETBLK)	 printk("st%d: Setting block size to %d bytes.\n", dev,		(STp->buffer)->b_data[9] * 65536 +		(STp->buffer)->b_data[10] * 256 +		(STp->buffer)->b_data[11]);       else if (cmd_in == MTSETDENSITY)	 printk("st%d: Setting density code to %x.\n", dev,		(STp->buffer)->b_data[4]);       else	 printk("st%d: Setting drive buffer code to %d.\n", dev,		((STp->buffer)->b_data[2] >> 4) & 7);#endif       break;     default:       printk("st%d: Unknown st_ioctl command %x.\n", dev, cmd_in);       return (-ENOSYS);     }   SCpnt = allocate_device(NULL, (STp->device)->index, 1);   SCpnt->sense_buffer[0] = 0;   SCpnt->request.dev = dev;   scsi_do_cmd(SCpnt,	       (void *) cmd, (void *) (STp->buffer)->b_data, ST_BLOCK_SIZE,	       st_sleep_done, timeout, MAX_RETRIES);   if (SCpnt->request.dev == dev) sleep_on( &(STp->waiting) );   ioctl_result = (STp->buffer)->last_result_fatal;   SCpnt->request.dev = -1;  /* Mark as not busy */   if (!ioctl_result) {     if (cmd_in == MTBSFM)       ioctl_result = st_int_ioctl(inode, file, MTFSF, 1);     else if (cmd_in == MTFSFM)       ioctl_result = st_int_ioctl(inode, file, MTBSF, 1);     else if (cmd_in == MTSETBLK) {       STp->block_size = arg;       if (arg != 0) {	 (STp->buffer)->buffer_blocks =	   ST_BUFFER_SIZE / STp->block_size;	 (STp->buffer)->buffer_size =	   (STp->buffer)->buffer_blocks * STp->block_size;       }       else {	 (STp->buffer)->buffer_blocks = 1;	 (STp->buffer)->buffer_size = ST_BUFFER_SIZE;       }       (STp->buffer)->buffer_bytes =	 (STp->buffer)->read_pointer = 0;     }     else if (cmd_in == MTSETDRVBUFFER)       STp->drv_buffer = arg;     else if (cmd_in == MTSETDENSITY)       STp->density = arg;     if (cmd_in == MTEOM || cmd_in == MTWEOF) {       STp->eof = ST_EOM_OK;       STp->eof_hit = 0;     }     else if (cmd_in != MTSETBLK && cmd_in != MTNOP) {       STp->eof = ST_NOEOF;       STp->eof_hit = 0;     }   }   return ioctl_result ;}/* The ioctl command */	static intst_ioctl(struct inode * inode,struct file * file,	 unsigned int cmd_in, unsigned long arg){   int dev = MINOR(inode->i_rdev);   int i, cmd, result;   struct mtop mtc;   struct mtpos mt_pos;   unsigned char scmd[10];   Scsi_Cmnd *SCpnt;   Scsi_Tape *STp;   dev = dev & 127;   STp = &(scsi_tapes[dev]);#ifdef DEBUG   if (!STp->in_use) {     printk("st%d: Incorrect device.\n", dev);     return (-EIO);   }#endif   cmd = cmd_in & IOCCMD_MASK;   if (cmd == (MTIOCTOP & IOCCMD_MASK)) {     if (((cmd_in & IOCSIZE_MASK) >> IOCSIZE_SHIFT) != sizeof(mtc))       return (-EINVAL);     i = verify_area(VERIFY_WRITE, (void *)arg, sizeof(mtc));     if (i)        return i;     memcpy_fromfs((char *) &mtc, (char *)arg, sizeof(struct mtop));     i = flush_buffer(inode, file, mtc.mt_op == MTSEEK ||		      mtc.mt_op == MTREW || mtc.mt_op == MTOFFL ||		      mtc.mt_op == MTRETEN || mtc.mt_op == MTEOM);     if (i < 0)       return i;     return st_int_ioctl(inode, file, mtc.mt_op, mtc.mt_count);   }   else if (cmd == (MTIOCGET & IOCCMD_MASK)) {     if (((cmd_in & IOCSIZE_MASK) >> IOCSIZE_SHIFT) != sizeof(struct mtget))       return (-EINVAL);     i = verify_area(VERIFY_WRITE, (void *)arg, sizeof(struct mtget));     if (i)       return i;     memcpy_tofs((char *)arg, (char *)(STp->buffer)->mt_status,		 sizeof(struct mtget));     return 0;   }   else if (cmd == (MTIOCPOS & IOCCMD_MASK)) {#ifdef DEBUG     printk("st%d: get tape position.\n", dev);#endif     if (((cmd_in & IOCSIZE_MASK) >> IOCSIZE_SHIFT) != sizeof(struct mtpos))       return (-EINVAL);     i = flush_buffer(inode, file, 0);     if (i < 0)       return i;     i = verify_area(VERIFY_WRITE, (void *)arg, sizeof(struct mtpos));     if (i)       return i;     SCpnt = allocate_device(NULL, (STp->device)->index, 1);     SCpnt->sense_buffer[0]=0;     memset (scmd, 0, 10);     if ((STp->device)->scsi_level < SCSI_2) {       scmd[0] = QFA_REQUEST_BLOCK;       scmd[4] = 3;     }     else {       scmd[0] = READ_POSITION;       scmd[1] = 1;     }     SCpnt->request.dev = dev;     SCpnt->sense_buffer[0] = 0;     scsi_do_cmd(SCpnt,		 (void *) scmd, (void *) (STp->buffer)->b_data,		 ST_BLOCK_SIZE, st_sleep_done, ST_TIMEOUT, MAX_READY_RETRIES);     if (SCpnt->request.dev == dev) sleep_on( &(STp->waiting) );          if ((STp->buffer)->last_result_fatal != 0) {       mt_pos.mt_blkno = (-1);#ifdef DEBUG       printk("st%d: Can't read tape position.\n", dev);#endif       result = (-EIO);     }     else {       result = 0;       if ((STp->device)->scsi_level < SCSI_2)	 mt_pos.mt_blkno = ((STp->buffer)->b_data[0] << 16) 	   + ((STp->buffer)->b_data[1] << 8) 	     + (STp->buffer)->b_data[2];       else	 mt_pos.mt_blkno = ((STp->buffer)->b_data[4] << 24)	   + ((STp->buffer)->b_data[5] << 16) 	     + ((STp->buffer)->b_data[6] << 8) 	       + (STp->buffer)->b_data[7];     }     SCpnt->request.dev = -1;  /* Mark as not busy */     memcpy_tofs((char *)arg, (char *) (&mt_pos), sizeof(struct mtpos));     return result;   }   else     return scsi_ioctl(STp->device, cmd_in, (void *) arg);}static struct file_operations st_fops = {   NULL,            /* lseek - default */   st_read,         /* read - general block-dev read */   st_write,        /* write - general block-dev write */   NULL,            /* readdir - bad */   NULL,            /* select */   st_ioctl,        /* ioctl */   NULL,            /* mmap */   scsi_tape_open,  /* open */   scsi_tape_close, /* release */   NULL		    /* fsync */};void st_attach(Scsi_Device * SDp){  scsi_tapes[NR_ST++].device = SDp;  if(NR_ST > MAX_ST) panic ("scsi_devices corrupt (st)");};unsigned long st_init1(unsigned long mem_start, unsigned long mem_end){  scsi_tapes = (Scsi_Tape *) mem_start;  mem_start += MAX_ST * sizeof(Scsi_Tape);  return mem_start;};/* Driver initialization */unsigned long st_init(unsigned long mem_start, unsigned long mem_end){  int i;  if (register_chrdev(MAJOR_NR,"st",&st_fops)) {    printk("Unable to get major %d for SCSI tapes\n",MAJOR_NR);    return mem_start;  }  if (NR_ST == 0) return mem_start;#ifdef DEBUG  printk("st: Init tape.\n");#endif  for (i=0; i < NR_ST; ++i) {    scsi_tapes[i].capacity = 0xfffff;    scsi_tapes[i].dirty = 0;    scsi_tapes[i].rw = ST_IDLE;    scsi_tapes[i].eof = ST_NOEOF;    scsi_tapes[i].waiting = NULL;    scsi_tapes[i].in_use = 0;    scsi_tapes[i].drv_buffer = 1;  /* Try buffering if no mode sense */    scsi_tapes[i].density = 0;  }  /* Allocate the buffers */  if (NR_ST == 1)    st_nbr_buffers = 1;  else    st_nbr_buffers = 2;  for (i=0; i < st_nbr_buffers; i++) {    st_buffers[i] = (ST_buffer *) mem_start;#ifdef DEBUG    printk("st: Buffer address: %p\n", st_buffers[i]);#endif    mem_start += sizeof(ST_buffer) - 1 + ST_BUFFER_BLOCKS * ST_BLOCK_SIZE;    st_buffers[i]->mt_status = (struct mtget *) mem_start;    mem_start += sizeof(struct mtget);    st_buffers[i]->in_use = 0;    st_buffers[i]->writing = 0;    /* "generic" status */    memset((void *) st_buffers[i]->mt_status, 0, sizeof(struct mtget));    st_buffers[i]->mt_status->mt_type = MT_ISSCSI1;  }  return mem_start;}