Import 2.1.89

[davej-history.git] / drivers / scsi / st.c

/*
 SCSI Tape Driver for Linux version 1.1 and newer. See the accompanying
 file README.st for more information.

 History:
 Rewritten from Dwayne Forsyth's SCSI tape driver by Kai Makisara.
 Contribution and ideas from several people including (in alphabetical
 order) Klaus Ehrenfried, Wolfgang Denk, Steve Hirsch, Andreas Koppenh"ofer,
 Michael Leodolter, Eyal Lebedinsky, J"org Weule, and Eric Youngdale.

 Copyright 1992 - 1997 Kai Makisara
 email Kai.Makisara@metla.fi

 Last modified: Wed Nov 5 23:39:52 1997 by makisara@home
 Some small formal changes - aeb, 950809
*/

#include <linux/module.h>

#include <linux/fs.h>
#include <linux/kernel.h>
#include <linux/sched.h>
#include <linux/mm.h>
#include <linux/init.h>
#include <linux/string.h>
#include <linux/errno.h>
#include <linux/mtio.h>
#include <linux/ioctl.h>
#include <linux/fcntl.h>
#include <asm/uaccess.h>
#include <asm/dma.h>
#include <asm/system.h>

/* The driver prints some debugging information on the console if DEBUG
 is defined and non-zero. */
#define DEBUG 0

/* The message level for the debug messages is currently set to KERN_NOTICE
 so that people can easily see the messages. Later when the debugging messages
 in the drivers are more widely classified, this may be changed to KERN_DEBUG. */
#define ST_DEB_MSG KERN_NOTICE

#define MAJOR_NR SCSI_TAPE_MAJOR
#include <linux/blk.h>

#include"scsi.h"
#include"hosts.h"
#include <scsi/scsi_ioctl.h>
#include"st.h"
#include"constants.h"

#ifdef MODULE
MODULE_PARM(buffer_kbs,"i");
MODULE_PARM(write_threshold_kbs,"i");
MODULE_PARM(max_buffers,"i");
static int buffer_kbs =0;
static int write_threshold_kbs =0;
static int max_buffers =0;
#endif

/* The default definitions have been moved to st_options.h */

#define ST_KILOBYTE 1024

#include"st_options.h"

#define ST_BUFFER_SIZE (ST_BUFFER_BLOCKS * ST_KILOBYTE)
#define ST_WRITE_THRESHOLD (ST_WRITE_THRESHOLD_BLOCKS * ST_KILOBYTE)

/* The buffer size should fit into the 24 bits for length in the
 6-byte SCSI read and write commands. */
#if ST_BUFFER_SIZE >= (2 << 24 - 1)
#error"Buffer size should not exceed (2 << 24 - 1) bytes!"
#endif

#if DEBUG
static int debugging =1;
#endif

#define MAX_RETRIES 0
#define MAX_WRITE_RETRIES 0
#define MAX_READY_RETRIES 5
#define NO_TAPE NOT_READY

#define ST_TIMEOUT (900 * HZ)
#define ST_LONG_TIMEOUT (14000 * HZ)

#define TAPE_NR(x) (MINOR(x) & ~(128 | ST_MODE_MASK))
#define TAPE_MODE(x) ((MINOR(x) & ST_MODE_MASK) >> ST_MODE_SHIFT)

/* Internal ioctl to set both density (uppermost 8 bits) and blocksize (lower
 24 bits) */
#define SET_DENS_AND_BLK 0x10001

static int st_nbr_buffers;
static ST_buffer **st_buffers;
static int st_buffer_size = ST_BUFFER_SIZE;
static int st_write_threshold = ST_WRITE_THRESHOLD;
static int st_max_buffers = ST_MAX_BUFFERS;

static Scsi_Tape * scsi_tapes = NULL;

static int modes_defined = FALSE;

static ST_buffer *new_tape_buffer(int,int);
static intenlarge_buffer(ST_buffer *,int,int);
static voidnormalize_buffer(ST_buffer *);

static intst_init(void);
static intst_attach(Scsi_Device *);
static intst_detect(Scsi_Device *);
static voidst_detach(Scsi_Device *);

struct Scsi_Device_Template st_template = {NULL,"tape","st", NULL, TYPE_TAPE,
 SCSI_TAPE_MAJOR,0,0,0,0,
 st_detect, st_init,
 NULL, st_attach, st_detach};

static intst_compression(Scsi_Tape *,int);

static intfind_partition(struct inode *);
static intupdate_partition(struct inode *);

static intst_int_ioctl(struct inode * inode,unsigned int cmd_in,
unsigned long arg);



\f
/* Convert the result to success code */
static int
st_chk_result(Scsi_Cmnd * SCpnt)
{
int dev =TAPE_NR(SCpnt->request.rq_dev);
int result = SCpnt->result;
unsigned char* sense = SCpnt->sense_buffer, scode;
#if DEBUG
const char*stp;
#endif

if(!result /* && SCpnt->sense_buffer[0] == 0 */)
return0;

 scode = sense[2] &0x0f;

#if DEBUG
if(debugging) {
printk(ST_DEB_MSG "st%d: Error: %x, cmd: %x %x %x %x %x %x Len: %d\n",
 dev, result,
 SCpnt->data_cmnd[0], SCpnt->data_cmnd[1], SCpnt->data_cmnd[2],
 SCpnt->data_cmnd[3], SCpnt->data_cmnd[4], SCpnt->data_cmnd[5],
 SCpnt->request_bufflen);
if(driver_byte(result) & DRIVER_SENSE)
print_sense("st", SCpnt);
else
printk("\n");
}
else
#endif
if(!(driver_byte(result) & DRIVER_SENSE) ||
((sense[0] &0x70) ==0x70&&
 scode != NO_SENSE &&
 scode != RECOVERED_ERROR &&
/* scode != UNIT_ATTENTION && */
 scode != BLANK_CHECK &&
 scode != VOLUME_OVERFLOW &&
 SCpnt->data_cmnd[0] != MODE_SENSE &&
 SCpnt->data_cmnd[0] != TEST_UNIT_READY)) {/* Abnormal conditions for tape */
if(driver_byte(result) & DRIVER_SENSE) {
printk(KERN_WARNING "st%d: Error with sense data: ", dev);
print_sense("st", SCpnt);
}
else
printk(KERN_WARNING "st%d: Error %x.\n", dev, result);
}

if((sense[0] &0x70) ==0x70&&
 scode == RECOVERED_ERROR
#if ST_RECOVERED_WRITE_FATAL
&& SCpnt->data_cmnd[0] != WRITE_6
&& SCpnt->data_cmnd[0] != WRITE_FILEMARKS
#endif
) {
 scsi_tapes[dev].recover_count++;
 scsi_tapes[dev].mt_status->mt_erreg += (1<< MT_ST_SOFTERR_SHIFT);
#if DEBUG
if(debugging) {
if(SCpnt->data_cmnd[0] == READ_6)
 stp ="read";
else if(SCpnt->data_cmnd[0] == WRITE_6)
 stp ="write";
else
 stp ="ioctl";
printk(ST_DEB_MSG "st%d: Recovered %s error (%d).\n", dev, stp,
 scsi_tapes[dev].recover_count);
}
#endif
if((sense[2] &0xe0) ==0)
return0;
}
return(-EIO);
}


/* Wakeup from interrupt */
static void
st_sleep_done(Scsi_Cmnd * SCpnt)
{
unsigned int st_nbr;
int remainder;
 Scsi_Tape * STp;

if((st_nbr =TAPE_NR(SCpnt->request.rq_dev)) < st_template.nr_dev) {
 STp = &(scsi_tapes[st_nbr]);
if((STp->buffer)->writing &&
(SCpnt->sense_buffer[0] &0x70) ==0x70&&
(SCpnt->sense_buffer[2] &0x40)) {
/* EOM at write-behind, has all been written? */
if((SCpnt->sense_buffer[0] &0x80) !=0)
 remainder = (SCpnt->sense_buffer[3] <<24) |
(SCpnt->sense_buffer[4] <<16) |
(SCpnt->sense_buffer[5] <<8) | SCpnt->sense_buffer[6];
else
 remainder =0;
if((SCpnt->sense_buffer[2] &0x0f) == VOLUME_OVERFLOW ||
 remainder >0)
(STp->buffer)->last_result = SCpnt->result;/* Error */
else
(STp->buffer)->last_result = INT_MAX;/* OK */
}
else
(STp->buffer)->last_result = SCpnt->result;
 SCpnt->request.rq_status = RQ_SCSI_DONE;
(STp->buffer)->last_SCpnt = SCpnt;

#if DEBUG
 STp->write_pending =0;
#endif
up(SCpnt->request.sem);
}
#if DEBUG
else if(debugging)
printk(KERN_ERR "st?: Illegal interrupt device %x\n", st_nbr);
#endif
}


/* Do the scsi command */
static Scsi_Cmnd *
st_do_scsi(Scsi_Cmnd *SCpnt, Scsi_Tape *STp,unsigned char*cmd,int bytes,
int timeout,int retries)
{
if(SCpnt == NULL)
if((SCpnt =scsi_allocate_device(NULL, STp->device,1)) == NULL) {
printk(KERN_ERR "st%d: Can't get SCSI request.\n",TAPE_NR(STp->devt));
return NULL;
}

 cmd[1] |= (SCpnt->lun <<5) &0xe0;
 STp->sem = MUTEX_LOCKED;
 SCpnt->request.sem = &(STp->sem);
 SCpnt->request.rq_status = RQ_SCSI_BUSY;
 SCpnt->request.rq_dev = STp->devt;

scsi_do_cmd(SCpnt, (void*)cmd, (STp->buffer)->b_data, bytes,
 st_sleep_done, timeout, retries);

down(SCpnt->request.sem);

(STp->buffer)->last_result_fatal =st_chk_result(SCpnt);

return SCpnt;
}


/* Handle the write-behind checking */
static void
write_behind_check(Scsi_Tape *STp)
{
 ST_buffer * STbuffer;
 ST_partstat * STps;

 STbuffer = STp->buffer;

#if DEBUG
if(STp->write_pending)
 STp->nbr_waits++;
else
 STp->nbr_finished++;
#endif

down(&(STp->sem));

(STp->buffer)->last_result_fatal =st_chk_result((STp->buffer)->last_SCpnt);
scsi_release_command((STp->buffer)->last_SCpnt);

if(STbuffer->writing < STbuffer->buffer_bytes)
memcpy(STbuffer->b_data,
 STbuffer->b_data + STbuffer->writing,
 STbuffer->buffer_bytes - STbuffer->writing);
 STbuffer->buffer_bytes -= STbuffer->writing;
 STps = &(STp->ps[STp->partition]);
if(STps->drv_block >=0) {
if(STp->block_size ==0)
 STps->drv_block++;
else
 STps->drv_block += STbuffer->writing / STp->block_size;
}
 STbuffer->writing =0;

return;
}


/* Step over EOF if it has been inadvertently crossed (ioctl not used because
 it messes up the block number). */
static int
cross_eof(Scsi_Tape *STp,int forward)
{
 Scsi_Cmnd *SCpnt;
unsigned char cmd[10];

 cmd[0] = SPACE;
 cmd[1] =0x01;/* Space FileMarks */
if(forward) {
 cmd[2] = cmd[3] =0;
 cmd[4] =1;
}
else
 cmd[2] = cmd[3] = cmd[4] =0xff;/* -1 filemarks */
 cmd[5] =0;
#if DEBUG
if(debugging)
printk(ST_DEB_MSG "st%d: Stepping over filemark %s.\n",
TAPE_NR(STp->devt), forward ?"forward":"backward");
#endif

 SCpnt =st_do_scsi(NULL, STp, cmd,0, STp->timeout, MAX_RETRIES);
if(!SCpnt)
return(-EBUSY);

scsi_release_command(SCpnt);
 SCpnt = NULL;

if((STp->buffer)->last_result !=0)
printk(KERN_ERR "st%d: Stepping over filemark %s failed.\n",
TAPE_NR(STp->devt), forward ?"forward":"backward");

return(STp->buffer)->last_result_fatal;
}


/* Flush the write buffer (never need to write if variable blocksize). */
static int
flush_write_buffer(Scsi_Tape *STp)
{
int offset, transfer, blks;
int result;
unsigned char cmd[10];
 Scsi_Cmnd *SCpnt;
 ST_partstat * STps;

if((STp->buffer)->writing) {
write_behind_check(STp);
if((STp->buffer)->last_result_fatal) {
#if DEBUG
if(debugging)
printk(ST_DEB_MSG "st%d: Async write error (flush) %x.\n",
TAPE_NR(STp->devt), (STp->buffer)->last_result);
#endif
if((STp->buffer)->last_result == INT_MAX)
return(-ENOSPC);
return(-EIO);
}
}

if(STp->block_size ==0)
return0;

 result =0;
if(STp->dirty ==1) {

 offset = (STp->buffer)->buffer_bytes;
 transfer = ((offset + STp->block_size -1) /
 STp->block_size) * STp->block_size;
#if DEBUG
if(debugging)
printk(ST_DEB_MSG "st%d: Flushing %d bytes.\n",TAPE_NR(STp->devt), transfer);
#endif
memset((STp->buffer)->b_data + offset,0, transfer - offset);

memset(cmd,0,10);
 cmd[0] = WRITE_6;
 cmd[1] =1;
 blks = transfer / STp->block_size;
 cmd[2] = blks >>16;
 cmd[3] = blks >>8;
 cmd[4] = blks;

 SCpnt =st_do_scsi(NULL, STp, cmd, transfer, STp->timeout, MAX_WRITE_RETRIES);
if(!SCpnt)
return(-EBUSY);

 STps = &(STp->ps[STp->partition]);
if((STp->buffer)->last_result_fatal !=0) {
if((SCpnt->sense_buffer[0] &0x70) ==0x70&&
(SCpnt->sense_buffer[2] &0x40) &&
(SCpnt->sense_buffer[2] &0x0f) == NO_SENSE) {
 STp->dirty =0;
(STp->buffer)->buffer_bytes =0;
 result = (-ENOSPC);
}
else{
printk(KERN_ERR "st%d: Error on flush.\n",TAPE_NR(STp->devt));
 result = (-EIO);
}
 STps->drv_block = (-1);
}
else{
if(STps->drv_block >=0)
 STps->drv_block += blks;
 STp->dirty =0;
(STp->buffer)->buffer_bytes =0;
}
scsi_release_command(SCpnt);
 SCpnt = NULL;
}
return result;
}


/* Flush the tape buffer. The tape will be positioned correctly unless
 seek_next is true. */
static int
flush_buffer(struct inode * inode,struct file * filp,int seek_next)
{
int backspace, result;
 Scsi_Tape * STp;
 ST_buffer * STbuffer;
 ST_partstat * STps;
int dev =TAPE_NR(inode->i_rdev);

 STp = &(scsi_tapes[dev]);
 STbuffer = STp->buffer;

/*
 * If there was a bus reset, block further access
 * to this device.
 */
if( STp->device->was_reset )
return(-EIO);

if(STp->ready != ST_READY)
return0;

 STps = &(STp->ps[STp->partition]);
if(STps->rw == ST_WRITING)/* Writing */
returnflush_write_buffer(STp);

if(STp->block_size ==0)
return0;

 backspace = ((STp->buffer)->buffer_bytes +
(STp->buffer)->read_pointer) / STp->block_size -
((STp->buffer)->read_pointer + STp->block_size -1) /
 STp->block_size;
(STp->buffer)->buffer_bytes =0;
(STp->buffer)->read_pointer =0;
 result =0;
if(!seek_next) {
if(STps->eof == ST_FM_HIT) {
 result =cross_eof(STp, FALSE);/* Back over the EOF hit */
if(!result)
 STps->eof = ST_NOEOF;
else{
if(STps->drv_file >=0)
 STps->drv_file++;
 STps->drv_block =0;
}
}
if(!result && backspace >0)
 result =st_int_ioctl(inode, MTBSR, backspace);
}
else if(STps->eof == ST_FM_HIT) {
if(STps->drv_file >=0)
 STps->drv_file++;
 STps->drv_block =0;
 STps->eof = ST_NOEOF;
}

return result;

}

\f/* Set the mode parameters */
static int
set_mode_densblk(struct inode * inode, Scsi_Tape *STp, ST_mode *STm)
{
int set_it = FALSE;
unsigned long arg;
int dev =TAPE_NR(inode->i_rdev);

if(!STp->density_changed &&
 STm->default_density >=0&&
 STm->default_density != STp->density) {
 arg = STm->default_density;
 set_it = TRUE;
}
else
 arg = STp->density;
 arg <<= MT_ST_DENSITY_SHIFT;
if(!STp->blksize_changed &&
 STm->default_blksize >=0&&
 STm->default_blksize != STp->block_size) {
 arg |= STm->default_blksize;
 set_it = TRUE;
}
else
 arg |= STp->block_size;
if(set_it &&
st_int_ioctl(inode, SET_DENS_AND_BLK, arg)) {
printk(KERN_WARNING
"st%d: Can't set default block size to %d bytes and density %x.\n",
 dev, STm->default_blksize, STm->default_density);
if(modes_defined)
return(-EINVAL);
}
return0;
}

\f
/* Open the device */
static int
scsi_tape_open(struct inode * inode,struct file * filp)
{
unsigned short flags;
int i, need_dma_buffer, new_session = FALSE;
unsigned char cmd[10];
 Scsi_Cmnd * SCpnt;
 Scsi_Tape * STp;
 ST_mode * STm;
 ST_partstat * STps;
int dev =TAPE_NR(inode->i_rdev);
int mode =TAPE_MODE(inode->i_rdev);

if(dev >= st_template.dev_max || !scsi_tapes[dev].device)
return(-ENXIO);

if( !scsi_block_when_processing_errors(scsi_tapes[dev].device) )
{
return-ENXIO;
}

 STp = &(scsi_tapes[dev]);
if(STp->in_use) {
#if DEBUG
printk(ST_DEB_MSG "st%d: Device already in use.\n", dev);
#endif
return(-EBUSY);
}
 STp->rew_at_close = (MINOR(inode->i_rdev) &0x80) ==0;

if(mode != STp->current_mode) {
#if DEBUG
if(debugging)
printk(ST_DEB_MSG "st%d: Mode change from %d to %d.\n",
 dev, STp->current_mode, mode);
#endif
 new_session = TRUE;
 STp->current_mode = mode;
}
 STm = &(STp->modes[STp->current_mode]);

/* Allocate buffer for this user */
 need_dma_buffer = STp->restr_dma;
for(i=0; i < st_nbr_buffers; i++)
if(!st_buffers[i]->in_use &&
(!need_dma_buffer || st_buffers[i]->dma))
break;
if(i >= st_nbr_buffers) {
 STp->buffer =new_tape_buffer(FALSE, need_dma_buffer);
if(STp->buffer == NULL) {
printk(KERN_WARNING "st%d: Can't allocate tape buffer.\n", dev);
return(-EBUSY);
}
}
else
 STp->buffer = st_buffers[i];
(STp->buffer)->in_use =1;
(STp->buffer)->writing =0;
(STp->buffer)->last_result_fatal =0;

 flags = filp->f_flags;
 STp->write_prot = ((flags & O_ACCMODE) == O_RDONLY);

 STp->dirty =0;
for(i=0; i < ST_NBR_PARTITIONS; i++) {
 STps = &(STp->ps[i]);
 STps->rw = ST_IDLE;
}
 STp->ready = ST_READY;
 STp->recover_count =0;
#if DEBUG
 STp->nbr_waits = STp->nbr_finished =0;
#endif

if(scsi_tapes[dev].device->host->hostt->module)
__MOD_INC_USE_COUNT(scsi_tapes[dev].device->host->hostt->module);
if(st_template.module)
__MOD_INC_USE_COUNT(st_template.module);

memset((void*) &cmd[0],0,10);
 cmd[0] = TEST_UNIT_READY;

 SCpnt =st_do_scsi(NULL, STp, cmd,0, STp->long_timeout, MAX_READY_RETRIES);
if(!SCpnt) {
if(scsi_tapes[dev].device->host->hostt->module)
__MOD_DEC_USE_COUNT(scsi_tapes[dev].device->host->hostt->module);
if(st_template.module)
__MOD_DEC_USE_COUNT(st_template.module);
return(-EBUSY);
}

if((SCpnt->sense_buffer[0] &0x70) ==0x70&&
(SCpnt->sense_buffer[2] &0x0f) == UNIT_ATTENTION) {/* New media? */
memset((void*) &cmd[0],0,10);
 cmd[0] = TEST_UNIT_READY;

 SCpnt =st_do_scsi(SCpnt, STp, cmd,0, STp->long_timeout, MAX_READY_RETRIES);

(STp->device)->was_reset =0;
 STp->partition = STp->new_partition =0;
if(STp->can_partitions)
 STp->nbr_partitions =1;/* This guess will be updated later if necessary */
for(i=0; i < ST_NBR_PARTITIONS; i++) {
 STps = &(STp->ps[i]);
 STps->rw = ST_IDLE;
 STps->eof = ST_NOEOF;
 STps->at_sm =0;
 STps->last_block_valid = FALSE;
 STps->drv_block =0;
 STps->drv_file =0;
}
 new_session = TRUE;
}

if((STp->buffer)->last_result_fatal !=0) {
if((STp->device)->scsi_level >= SCSI_2 &&
(SCpnt->sense_buffer[0] &0x70) ==0x70&&
(SCpnt->sense_buffer[2] &0x0f) == NOT_READY &&
 SCpnt->sense_buffer[12] ==0x3a) {/* Check ASC */
 STp->ready = ST_NO_TAPE;
}else
 STp->ready = ST_NOT_READY;
scsi_release_command(SCpnt);
 SCpnt = NULL;
 STp->density =0;/* Clear the erroneous "residue" */
 STp->write_prot =0;
 STp->block_size =0;
 STp->ps[0].drv_file = STp->ps[0].drv_block =0;
 STp->partition = STp->new_partition =0;
 STp->door_locked = ST_UNLOCKED;
 STp->in_use =1;
return0;
}

if(STp->omit_blklims)
 STp->min_block = STp->max_block = (-1);
else{
memset((void*) &cmd[0],0,10);
 cmd[0] = READ_BLOCK_LIMITS;

 SCpnt =st_do_scsi(SCpnt, STp, cmd,6, STp->timeout, MAX_READY_RETRIES);

if(!SCpnt->result && !SCpnt->sense_buffer[0]) {
 STp->max_block = ((STp->buffer)->b_data[1] <<16) |
((STp->buffer)->b_data[2] <<8) | (STp->buffer)->b_data[3];
 STp->min_block = ((STp->buffer)->b_data[4] <<8) |
(STp->buffer)->b_data[5];
#if DEBUG
if(debugging)
printk(ST_DEB_MSG "st%d: Block limits %d - %d bytes.\n", dev, STp->min_block,
 STp->max_block);
#endif
}
else{
 STp->min_block = STp->max_block = (-1);
#if DEBUG
if(debugging)
printk(ST_DEB_MSG "st%d: Can't read block limits.\n", dev);
#endif
}
}

memset((void*) &cmd[0],0,10);
 cmd[0] = MODE_SENSE;
 cmd[4] =12;

 SCpnt =st_do_scsi(SCpnt, STp, cmd,12, STp->timeout, MAX_READY_RETRIES);

if((STp->buffer)->last_result_fatal !=0) {
#if DEBUG
if(debugging)
printk(ST_DEB_MSG "st%d: No Mode Sense.\n", dev);
#endif
 STp->block_size = ST_DEFAULT_BLOCK;/* Educated guess (?) */
(STp->buffer)->last_result_fatal =0;/* Prevent error propagation */
 STp->drv_write_prot =0;
}
else{

#if DEBUG
if(debugging)
printk(ST_DEB_MSG "st%d: Mode sense. Length %d, medium %x, WBS %x, BLL %d\n",
 dev,
(STp->buffer)->b_data[0], (STp->buffer)->b_data[1],
(STp->buffer)->b_data[2], (STp->buffer)->b_data[3]);
#endif

if((STp->buffer)->b_data[3] >=8) {
 STp->drv_buffer = ((STp->buffer)->b_data[2] >>4) &7;
 STp->density = (STp->buffer)->b_data[4];
 STp->block_size = (STp->buffer)->b_data[9] *65536+
(STp->buffer)->b_data[10] *256+ (STp->buffer)->b_data[11];
#if DEBUG
if(debugging)
printk(ST_DEB_MSG "st%d: Density %x, tape length: %x, drv buffer: %d\n",
 dev, STp->density, (STp->buffer)->b_data[5] *65536+
(STp->buffer)->b_data[6] *256+ (STp->buffer)->b_data[7],
 STp->drv_buffer);
#endif
}

if(STp->block_size > (STp->buffer)->buffer_size &&
!enlarge_buffer(STp->buffer, STp->block_size, STp->restr_dma)) {
printk(KERN_NOTICE "st%d: Blocksize %d too large for buffer.\n", dev,
 STp->block_size);
(STp->buffer)->in_use =0;
 STp->buffer = NULL;
if(scsi_tapes[dev].device->host->hostt->module)
__MOD_DEC_USE_COUNT(scsi_tapes[dev].device->host->hostt->module);
if(st_template.module)
__MOD_DEC_USE_COUNT(st_template.module);
return(-EIO);
}
 STp->drv_write_prot = ((STp->buffer)->b_data[2] &0x80) !=0;
}
scsi_release_command(SCpnt);
 SCpnt = NULL;

if(STp->block_size >0)
(STp->buffer)->buffer_blocks = st_buffer_size / STp->block_size;
else
(STp->buffer)->buffer_blocks =1;
(STp->buffer)->buffer_bytes = (STp->buffer)->read_pointer =0;

#if DEBUG
if(debugging)
printk(ST_DEB_MSG "st%d: Block size: %d, buffer size: %d (%d blocks).\n", dev,
 STp->block_size, (STp->buffer)->buffer_size,
(STp->buffer)->buffer_blocks);
#endif

if(STp->drv_write_prot) {
 STp->write_prot =1;
#if DEBUG
if(debugging)
printk(ST_DEB_MSG "st%d: Write protected\n", dev);
#endif
if((flags & O_ACCMODE) == O_WRONLY || (flags & O_ACCMODE) == O_RDWR) {
(STp->buffer)->in_use =0;
 STp->buffer = NULL;
if(scsi_tapes[dev].device->host->hostt->module)
__MOD_DEC_USE_COUNT(scsi_tapes[dev].device->host->hostt->module);
if(st_template.module)
__MOD_DEC_USE_COUNT(st_template.module);
return(-EROFS);
}
}

if(STp->can_partitions && STp->nbr_partitions <1) {
/* This code is reached when the device is opened for the first time
 after the driver has been initialized with tape in the drive and the
 partition support has been enabled. */
#if DEBUG
if(debugging)
printk(ST_DEB_MSG "st%d: Updating partition number in status.\n", dev);
#endif
if((STp->partition =find_partition(inode)) <0) {
(STp->buffer)->in_use =0;
 STp->buffer = NULL;
if(scsi_tapes[dev].device->host->hostt->module)
__MOD_DEC_USE_COUNT(scsi_tapes[dev].device->host->hostt->module);
if(st_template.module)
__MOD_DEC_USE_COUNT(st_template.module);
return STp->partition;
}
 STp->new_partition = STp->partition;
 STp->nbr_partitions =1;/* This guess will be updated when necessary */
}

if(new_session) {/* Change the drive parameters for the new mode */
 STp->density_changed = STp->blksize_changed = FALSE;
 STp->compression_changed = FALSE;
if(!(STm->defaults_for_writes) &&
(i =set_mode_densblk(inode, STp, STm)) <0) {
(STp->buffer)->in_use =0;
 STp->buffer = NULL;
if(scsi_tapes[dev].device->host->hostt->module)
__MOD_DEC_USE_COUNT(scsi_tapes[dev].device->host->hostt->module);
if(st_template.module)
__MOD_DEC_USE_COUNT(st_template.module);
return i;
}
if(STp->default_drvbuffer !=0xff) {
if(st_int_ioctl(inode, MTSETDRVBUFFER, STp->default_drvbuffer))
printk(KERN_WARNING "st%d: Can't set default drive buffering to %d.\n",
 dev, STp->default_drvbuffer);
}
}

 STp->in_use =1;

return0;
}

\f
/* Close the device*/
static int
scsi_tape_close(struct inode * inode,struct file * filp)
{
int result =0, result2;
static unsigned char cmd[10];
 Scsi_Cmnd * SCpnt;
 Scsi_Tape * STp;
 ST_mode * STm;
 ST_partstat * STps;

 kdev_t devt = inode->i_rdev;
int dev;

 dev =TAPE_NR(devt);
 STp = &(scsi_tapes[dev]);
 STm = &(STp->modes[STp->current_mode]);
 STps = &(STp->ps[STp->partition]);

if(STp->can_partitions &&
(result =update_partition(inode)) <0) {
#if DEBUG
if(debugging)
printk(ST_DEB_MSG "st%d: update_partition at close failed.\n", dev);
#endif
goto out;
}

if( STps->rw == ST_WRITING && !(STp->device)->was_reset) {

 result =flush_write_buffer(STp);

#if DEBUG
if(debugging) {
printk(ST_DEB_MSG "st%d: File length %ld bytes.\n",
 dev, (long)(filp->f_pos));
printk(ST_DEB_MSG "st%d: Async write waits %d, finished %d.\n",
 dev, STp->nbr_waits, STp->nbr_finished);
}
#endif

if(result ==0|| result == (-ENOSPC)) {

memset(cmd,0,10);
 cmd[0] = WRITE_FILEMARKS;
 cmd[4] =1+ STp->two_fm;

 SCpnt =st_do_scsi(NULL, STp, cmd,0, STp->timeout, MAX_WRITE_RETRIES);
if(!SCpnt)
goto out;

if((STp->buffer)->last_result_fatal !=0&&
((SCpnt->sense_buffer[0] &0x70) !=0x70||
(SCpnt->sense_buffer[2] &0x4f) !=0x40||
((SCpnt->sense_buffer[0] &0x80) !=0&&
(SCpnt->sense_buffer[3] | SCpnt->sense_buffer[4] |
 SCpnt->sense_buffer[5] |
 SCpnt->sense_buffer[6]) ==0))) {
/* Filter out successful write at EOM */
scsi_release_command(SCpnt);
 SCpnt = NULL;
printk(KERN_ERR "st%d: Error on write filemark.\n", dev);
if(result ==0)
 result = (-EIO);
}
else{
scsi_release_command(SCpnt);
 SCpnt = NULL;
if(STps->drv_file >=0)
 STps->drv_file++ ;
 STps->drv_block =0;
if(STp->two_fm)
cross_eof(STp, FALSE);
 STps->eof = ST_FM;
}
}

#if DEBUG
if(debugging)
printk(ST_DEB_MSG "st%d: Buffer flushed, %d EOF(s) written\n",
 dev, cmd[4]);
#endif
}
else if(!STp->rew_at_close) {
 STps = &(STp->ps[STp->partition]);
if(!STm->sysv || STps->rw != ST_READING) {
if(STp->can_bsr)
 result =flush_buffer(inode, filp,0);
else if(STps->eof == ST_FM_HIT) {
 result =cross_eof(STp, FALSE);
if(result) {
if(STps->drv_file >=0)
 STps->drv_file++;
 STps->drv_block =0;
 STps->eof = ST_FM;
}
else
 STps->eof = ST_NOEOF;
}
}
else if((STps->eof == ST_NOEOF &&
!(result =cross_eof(STp, TRUE))) ||
 STps->eof == ST_FM_HIT) {
if(STps->drv_file >=0)
 STps->drv_file++;
 STps->drv_block =0;
 STps->eof = ST_FM;
}
}

out:
if(STp->rew_at_close) {
 result2 =st_int_ioctl(inode, MTREW,1);
if(result ==0)
 result = result2;
}

if(STp->door_locked == ST_LOCKED_AUTO)
st_int_ioctl(inode, MTUNLOCK,0);

if(STp->buffer != NULL) {
normalize_buffer(STp->buffer);
(STp->buffer)->in_use =0;
}

 STp->in_use =0;
if(scsi_tapes[dev].device->host->hostt->module)
__MOD_DEC_USE_COUNT(scsi_tapes[dev].device->host->hostt->module);
if(st_template.module)
__MOD_DEC_USE_COUNT(st_template.module);

return result;
}

\f
/* Write command */
static ssize_t
st_write(struct file * filp,const char* buf,size_t count, loff_t *ppos)
{
struct inode *inode = filp->f_dentry->d_inode;
 ssize_t total;
 ssize_t i, do_count, blks, retval, transfer;
int write_threshold;
int doing_write =0;
static unsigned char cmd[10];
const char*b_point;
 Scsi_Cmnd * SCpnt = NULL;
 Scsi_Tape * STp;
 ST_mode * STm;
 ST_partstat * STps;
int dev =TAPE_NR(inode->i_rdev);

 STp = &(scsi_tapes[dev]);

/*
 * If we are in the middle of error recovery, don't let anyone
 * else try and use this device. Also, if error recovery fails, it
 * may try and take the device offline, in which case all further
 * access to the device is prohibited.
 */
if( !scsi_block_when_processing_errors(STp->device) )
{
return-ENXIO;
}

if(ppos != &filp->f_pos) {
/* "A request was outside the capabilities of the device." */
return-ENXIO;
}

if(STp->ready != ST_READY) {
if(STp->ready == ST_NO_TAPE)
return(-ENOMEDIUM);
else
return(-EIO);
}
 STm = &(STp->modes[STp->current_mode]);
if(!STm->defined)
return(-ENXIO);
if(count ==0)
return0;

/*
 * If there was a bus reset, block further access
 * to this device.
 */
if( STp->device->was_reset )
return(-EIO);

#if DEBUG
if(!STp->in_use) {
printk(ST_DEB_MSG "st%d: Incorrect device.\n", dev);
return(-EIO);
}
#endif

if(STp->can_partitions &&
(retval =update_partition(inode)) <0)
return retval;
 STps = &(STp->ps[STp->partition]);

if(STp->write_prot)
return(-EACCES);

if(STp->block_size ==0&&
 count > (STp->buffer)->buffer_size &&
!enlarge_buffer(STp->buffer, count, STp->restr_dma))
return(-EOVERFLOW);

if(STp->do_auto_lock && STp->door_locked == ST_UNLOCKED &&
!st_int_ioctl(inode, MTLOCK,0))
 STp->door_locked = ST_LOCKED_AUTO;

if(STps->rw == ST_READING) {
 retval =flush_buffer(inode, filp,0);
if(retval)
return retval;
 STps->rw = ST_WRITING;
}
else if(STps->rw != ST_WRITING &&
 STps->drv_file ==0&& STps->drv_block ==0) {
if((retval =set_mode_densblk(inode, STp, STm)) <0)
return retval;
if(STm->default_compression != ST_DONT_TOUCH &&
!(STp->compression_changed)) {
if(st_compression(STp, (STm->default_compression == ST_YES))) {
printk(KERN_WARNING "st%d: Can't set default compression.\n",
 dev);
if(modes_defined)
return(-EINVAL);
}
}
}

if((STp->buffer)->writing) {
write_behind_check(STp);
if((STp->buffer)->last_result_fatal) {
#if DEBUG
if(debugging)
printk(ST_DEB_MSG "st%d: Async write error (write) %x.\n", dev,
(STp->buffer)->last_result);
#endif
if((STp->buffer)->last_result == INT_MAX)
 STps->eof = ST_EOM_OK;
else
 STps->eof = ST_EOM_ERROR;
}
}
if(STps->eof == ST_EOM_OK)
return(-ENOSPC);
else if(STps->eof == ST_EOM_ERROR)
return(-EIO);

/* Check the buffer readability in cases where copy_user might catch
 the problems after some tape movement. */
if(STp->block_size !=0&&
(copy_from_user(&i, buf,1) !=0||
copy_from_user(&i, buf + count -1,1) !=0))
return(-EFAULT);

if(!STm->do_buffer_writes) {
if(STp->block_size !=0&& (count % STp->block_size) !=0)
return(-EIO);/* Write must be integral number of blocks */
 write_threshold =1;
}
else
 write_threshold = (STp->buffer)->buffer_blocks * STp->block_size;
if(!STm->do_async_writes)
 write_threshold--;

 total = count;

memset(cmd,0,10);
 cmd[0] = WRITE_6;
 cmd[1] = (STp->block_size !=0);

 STps->rw = ST_WRITING;

 b_point = buf;
while((STp->block_size ==0&& !STm->do_async_writes && count >0) ||
(STp->block_size !=0&&
(STp->buffer)->buffer_bytes + count > write_threshold))
{
 doing_write =1;
if(STp->block_size ==0)
 do_count = count;
else{
 do_count = (STp->buffer)->buffer_blocks * STp->block_size -
(STp->buffer)->buffer_bytes;
if(do_count > count)
 do_count = count;
}

 i =copy_from_user((STp->buffer)->b_data +
(STp->buffer)->buffer_bytes, b_point, do_count);
if(i) {
if(SCpnt != NULL)
{
scsi_release_command(SCpnt);
 SCpnt = NULL;
}
return(-EFAULT);
}

if(STp->block_size ==0)
 blks = transfer = do_count;
else{
 blks = ((STp->buffer)->buffer_bytes + do_count) /
 STp->block_size;
 transfer = blks * STp->block_size;
}
 cmd[2] = blks >>16;
 cmd[3] = blks >>8;
 cmd[4] = blks;

 SCpnt =st_do_scsi(SCpnt, STp, cmd, transfer, STp->timeout, MAX_WRITE_RETRIES);
if(!SCpnt)
return(-EBUSY);

if((STp->buffer)->last_result_fatal !=0) {
#if DEBUG
if(debugging)
printk(ST_DEB_MSG "st%d: Error on write:\n", dev);
#endif
if((SCpnt->sense_buffer[0] &0x70) ==0x70&&
(SCpnt->sense_buffer[2] &0x40)) {
if(STp->block_size !=0&& (SCpnt->sense_buffer[0] &0x80) !=0)
 transfer = (SCpnt->sense_buffer[3] <<24) |
(SCpnt->sense_buffer[4] <<16) |
(SCpnt->sense_buffer[5] <<8) | SCpnt->sense_buffer[6];
else if(STp->block_size ==0&&
(SCpnt->sense_buffer[2] &0x0f) == VOLUME_OVERFLOW)
 transfer = do_count;
else
 transfer =0;
if(STp->block_size !=0)
 transfer *= STp->block_size;
if(transfer <= do_count) {
 filp->f_pos += do_count - transfer;
 count -= do_count - transfer;
if(STps->drv_block >=0) {
if(STp->block_size ==0&& transfer < do_count)
 STps->drv_block++;
else if(STp->block_size !=0)
 STps->drv_block += (do_count - transfer) / STp->block_size;
}
 STps->eof = ST_EOM_OK;
 retval = (-ENOSPC);/* EOM within current request */
#if DEBUG
if(debugging)
printk(ST_DEB_MSG "st%d: EOM with %d bytes unwritten.\n",
 dev, transfer);
#endif
}
else{
 STps->eof = ST_EOM_ERROR;
 STps->drv_block = (-1);/* Too cautious? */
 retval = (-EIO);/* EOM for old data */
#if DEBUG
if(debugging)
printk(ST_DEB_MSG "st%d: EOM with lost data.\n", dev);
#endif
}
}
else{
 STps->drv_block = (-1);/* Too cautious? */
 retval = (-EIO);
}

scsi_release_command(SCpnt);
 SCpnt = NULL;
(STp->buffer)->buffer_bytes =0;
 STp->dirty =0;
if(count < total)
return total - count;
else
return retval;
}
 filp->f_pos += do_count;
 b_point += do_count;
 count -= do_count;
if(STps->drv_block >=0) {
if(STp->block_size ==0)
 STps->drv_block++;
else
 STps->drv_block += blks;
}
(STp->buffer)->buffer_bytes =0;
 STp->dirty =0;
}
if(count !=0) {
 STp->dirty =1;
 i =copy_from_user((STp->buffer)->b_data +
(STp->buffer)->buffer_bytes, b_point, count);
if(i) {
if(SCpnt != NULL)
{
scsi_release_command(SCpnt);
 SCpnt = NULL;
}
return(-EFAULT);
}
 filp->f_pos += count;
(STp->buffer)->buffer_bytes += count;
 count =0;
}

if(doing_write && (STp->buffer)->last_result_fatal !=0) {
scsi_release_command(SCpnt);
 SCpnt = NULL;
return(STp->buffer)->last_result_fatal;
}

if(STm->do_async_writes &&
(((STp->buffer)->buffer_bytes >= STp->write_threshold &&
(STp->buffer)->buffer_bytes >= STp->block_size) ||
 STp->block_size ==0) ) {
/* Schedule an asynchronous write */
if(!SCpnt) {
 SCpnt =scsi_allocate_device(NULL, STp->device,1);
if(!SCpnt)
return(-EBUSY);
}
if(STp->block_size ==0)
(STp->buffer)->writing = (STp->buffer)->buffer_bytes;
else
(STp->buffer)->writing = ((STp->buffer)->buffer_bytes /
 STp->block_size) * STp->block_size;
 STp->dirty = !((STp->buffer)->writing ==
(STp->buffer)->buffer_bytes);

if(STp->block_size ==0)
 blks = (STp->buffer)->writing;
else
 blks = (STp->buffer)->writing / STp->block_size;
 cmd[2] = blks >>16;
 cmd[3] = blks >>8;
 cmd[4] = blks;
 STp->sem = MUTEX_LOCKED;
 SCpnt->request.sem = &(STp->sem);
 SCpnt->request.rq_status = RQ_SCSI_BUSY;
 SCpnt->request.rq_dev = STp->devt;
#if DEBUG
 STp->write_pending =1;
#endif

scsi_do_cmd(SCpnt,
(void*) cmd, (STp->buffer)->b_data,
(STp->buffer)->writing,
 st_sleep_done, STp->timeout, MAX_WRITE_RETRIES);
}
else if(SCpnt != NULL)
{
scsi_release_command(SCpnt);
 SCpnt = NULL;
}
 STps->at_sm &= (total ==0);
if(total >0)
 STps->eof = ST_NOEOF;

return( total);
}
\f
/* Read data from the tape. Returns zero in the normal case, one if the
 eof status has changed, and the negative error code in case of a
 fatal error. Otherwise updates the buffer and the eof state. */
static long
read_tape(struct inode *inode,long count, Scsi_Cmnd **aSCpnt)
{
int transfer, blks, bytes;
static unsigned char cmd[10];
 Scsi_Cmnd *SCpnt;
 Scsi_Tape *STp;
 ST_mode * STm;
 ST_partstat * STps;
int dev =TAPE_NR(inode->i_rdev);
int retval =0;

if(count ==0)
return0;

 STp = &(scsi_tapes[dev]);
 STm = &(STp->modes[STp->current_mode]);
 STps = &(STp->ps[STp->partition]);
if(STps->eof == ST_FM_HIT)
return1;

memset(cmd,0,10);
 cmd[0] = READ_6;
 cmd[1] = (STp->block_size !=0);
if(STp->block_size ==0)
 blks = bytes = count;
else{
if(STm->do_read_ahead) {
 blks = (STp->buffer)->buffer_blocks;
 bytes = blks * STp->block_size;
}
else{
 bytes = count;
if(bytes > (STp->buffer)->buffer_size)
 bytes = (STp->buffer)->buffer_size;
 blks = bytes / STp->block_size;
 bytes = blks * STp->block_size;
}
}
 cmd[2] = blks >>16;
 cmd[3] = blks >>8;
 cmd[4] = blks;

 SCpnt = *aSCpnt;
 SCpnt =st_do_scsi(SCpnt, STp, cmd, bytes, STp->timeout, MAX_RETRIES);
*aSCpnt = SCpnt;
if(!SCpnt)
return(-EBUSY);

(STp->buffer)->read_pointer =0;
 STps->at_sm =0;


/* Something to check */
if((STp->buffer)->last_result_fatal) {
 retval =1;
#if DEBUG
if(debugging)
printk(ST_DEB_MSG "st%d: Sense: %2x %2x %2x %2x %2x %2x %2x %2x\n",
 dev,
 SCpnt->sense_buffer[0], SCpnt->sense_buffer[1],
 SCpnt->sense_buffer[2], SCpnt->sense_buffer[3],
 SCpnt->sense_buffer[4], SCpnt->sense_buffer[5],
 SCpnt->sense_buffer[6], SCpnt->sense_buffer[7]);
#endif
if((SCpnt->sense_buffer[0] &0x70) ==0x70) {/* extended sense */

if((SCpnt->sense_buffer[2] &0x0f) == BLANK_CHECK)
 SCpnt->sense_buffer[2] &=0xcf;/* No need for EOM in this case */

if((SCpnt->sense_buffer[2] &0xe0) !=0) {/* EOF, EOM, or ILI */
/* Compute the residual count */
if((SCpnt->sense_buffer[0] &0x80) !=0)
 transfer = (SCpnt->sense_buffer[3] <<24) |
(SCpnt->sense_buffer[4] <<16) |
(SCpnt->sense_buffer[5] <<8) | SCpnt->sense_buffer[6];
else
 transfer =0;
if(STp->block_size ==0&&
(SCpnt->sense_buffer[2] &0x0f) == MEDIUM_ERROR)
 transfer = bytes;

if(SCpnt->sense_buffer[2] &0x20) {/* ILI */
if(STp->block_size ==0) {
if(transfer <=0)
 transfer =0;
(STp->buffer)->buffer_bytes = bytes - transfer;
}
else{
scsi_release_command(SCpnt);
 SCpnt = *aSCpnt = NULL;
if(transfer == blks) {/* We did not get anything, error */
printk(KERN_NOTICE "st%d: Incorrect block size.\n", dev);
if(STps->drv_block >=0)
 STps->drv_block += blks - transfer +1;
st_int_ioctl(inode, MTBSR,1);
return(-EIO);
}
/* We have some data, deliver it */
(STp->buffer)->buffer_bytes = (blks - transfer) *
 STp->block_size;
#if DEBUG
if(debugging)
printk(ST_DEB_MSG
"st%d: ILI but enough data received %ld %d.\n",
 dev, count, (STp->buffer)->buffer_bytes);
#endif
if(STps->drv_block >=0)
 STps->drv_block +=1;
if(st_int_ioctl(inode, MTBSR,1))
return(-EIO);
}
}
else if(SCpnt->sense_buffer[2] &0x80) {/* FM overrides EOM */
if(STps->eof != ST_FM_HIT)
 STps->eof = ST_FM_HIT;
else
 STps->eof = ST_EOD_2;
if(STp->block_size ==0)
(STp->buffer)->buffer_bytes =0;
else
(STp->buffer)->buffer_bytes =
 bytes - transfer * STp->block_size;
#if DEBUG
if(debugging)
printk(ST_DEB_MSG
"st%d: EOF detected (%d bytes read).\n",
 dev, (STp->buffer)->buffer_bytes);
#endif
}
else if(SCpnt->sense_buffer[2] &0x40) {
if(STps->eof == ST_FM)
 STps->eof = ST_EOD_1;
else
 STps->eof = ST_EOM_OK;
if(STp->block_size ==0)
(STp->buffer)->buffer_bytes = bytes - transfer;
else
(STp->buffer)->buffer_bytes =
 bytes - transfer * STp->block_size;
#if DEBUG
if(debugging)
printk(ST_DEB_MSG "st%d: EOM detected (%d bytes read).\n",
 dev, (STp->buffer)->buffer_bytes);
#endif
}
}/* end of EOF, EOM, ILI test */
else{/* nonzero sense key */
#if DEBUG
if(debugging)
printk(ST_DEB_MSG "st%d: Tape error while reading.\n", dev);
#endif
 STps->drv_block = (-1);
if(STps->eof == ST_FM &&
(SCpnt->sense_buffer[2] &0x0f) == BLANK_CHECK) {
#if DEBUG
if(debugging)
printk(ST_DEB_MSG
"st%d: Zero returned for first BLANK CHECK after EOF.\n",
 dev);
#endif
 STps->eof = ST_EOD_2;/* First BLANK_CHECK after FM */
}
else/* Some other extended sense code */
 retval = (-EIO);
}
}/* End of extended sense test */
else{/* Non-extended sense */
 retval = (STp->buffer)->last_result_fatal;
}

}/* End of error handling */
else/* Read successful */
(STp->buffer)->buffer_bytes = bytes;

if(STps->drv_block >=0) {
if(STp->block_size ==0)
 STps->drv_block++;
else
 STps->drv_block += (STp->buffer)->buffer_bytes / STp->block_size;
}

return retval;
}

\f
/* Read command */
static ssize_t
st_read(struct file * filp,char* buf,size_t count, loff_t *ppos)
{
struct inode * inode = filp->f_dentry->d_inode;
 ssize_t total;
 ssize_t i, transfer;
int special;
 Scsi_Cmnd * SCpnt = NULL;
 Scsi_Tape * STp;
 ST_mode * STm;
 ST_partstat * STps;
int dev =TAPE_NR(inode->i_rdev);

 STp = &(scsi_tapes[dev]);

/*
 * If we are in the middle of error recovery, don't let anyone
 * else try and use this device. Also, if error recovery fails, it
 * may try and take the device offline, in which case all further
 * access to the device is prohibited.
 */
if( !scsi_block_when_processing_errors(STp->device) )
{
return-ENXIO;
}

if(ppos != &filp->f_pos) {
/* "A request was outside the capabilities of the device." */
return-ENXIO;
}

if(STp->ready != ST_READY) {
if(STp->ready == ST_NO_TAPE)
return(-ENOMEDIUM);
else
return(-EIO);
}
 STm = &(STp->modes[STp->current_mode]);
if(!STm->defined)
return(-ENXIO);
#if DEBUG
if(!STp->in_use) {
printk(ST_DEB_MSG "st%d: Incorrect device.\n", dev);
return(-EIO);
}
#endif

if(STp->can_partitions &&
(total =update_partition(inode)) <0)
return total;

if(STp->block_size ==0&&
 count > (STp->buffer)->buffer_size &&
!enlarge_buffer(STp->buffer, count, STp->restr_dma))
return(-EOVERFLOW);

if(!(STm->do_read_ahead) && STp->block_size !=0&&
(count % STp->block_size) !=0)
return(-EIO);/* Read must be integral number of blocks */

if(STp->do_auto_lock && STp->door_locked == ST_UNLOCKED &&
!st_int_ioctl(inode, MTLOCK,0))
 STp->door_locked = ST_LOCKED_AUTO;

 STps = &(STp->ps[STp->partition]);
if(STps->rw == ST_WRITING) {
 transfer =flush_buffer(inode, filp,0);
if(transfer)
return transfer;
 STps->rw = ST_READING;
}

#if DEBUG
if(debugging && STps->eof != ST_NOEOF)
printk(ST_DEB_MSG "st%d: EOF/EOM flag up (%d). Bytes %d\n", dev,
 STps->eof, (STp->buffer)->buffer_bytes);
#endif
if((STp->buffer)->buffer_bytes ==0&&
 STps->eof >= ST_EOD_1) {
if(STps->eof < ST_EOD) {
 STps->eof +=1;
return0;
}
return(-EIO);/* EOM or Blank Check */
}

/* Check the buffer writability before any tape movement. Don't alter
 buffer data. */
if(copy_from_user(&i, buf,1) !=0||
copy_to_user(buf, &i,1) !=0||
copy_from_user(&i, buf + count -1,1) !=0||
copy_to_user(buf + count -1, &i,1) !=0)
return(-EFAULT);

 STps->rw = ST_READING;


/* Loop until enough data in buffer or a special condition found */
for(total =0, special =0; total < count && !special; ) {

/* Get new data if the buffer is empty */
if((STp->buffer)->buffer_bytes ==0) {
 special =read_tape(inode, count - total, &SCpnt);
if(special <0) {/* No need to continue read */
if(SCpnt != NULL)
{
scsi_release_command(SCpnt);
}
return special;
}
}

/* Move the data from driver buffer to user buffer */
if((STp->buffer)->buffer_bytes >0) {
#if DEBUG
if(debugging && STps->eof != ST_NOEOF)
printk(ST_DEB_MSG "st%d: EOF up (%d). Left %d, needed %d.\n", dev,
 STps->eof, (STp->buffer)->buffer_bytes, count - total);
#endif
 transfer = (STp->buffer)->buffer_bytes < count - total ?
(STp->buffer)->buffer_bytes : count - total;
 i =copy_to_user(buf, (STp->buffer)->b_data +
(STp->buffer)->read_pointer, transfer);
if(i) {
if(SCpnt != NULL)
{
scsi_release_command(SCpnt);
 SCpnt = NULL;
}
return(-EFAULT);
}
 filp->f_pos += transfer;
 buf += transfer;
 total += transfer;
(STp->buffer)->buffer_bytes -= transfer;
(STp->buffer)->read_pointer += transfer;
}

if(STp->block_size ==0)
break;/* Read only one variable length block */

}/* for (total = 0, special = 0; total < count && !special; ) */

if(SCpnt != NULL)
{
scsi_release_command(SCpnt);
 SCpnt = NULL;
}

/* Change the eof state if no data from tape or buffer */
if(total ==0) {
if(STps->eof == ST_FM_HIT) {
 STps->eof = ST_FM;
 STps->drv_block =0;
if(STps->drv_file >=0)
 STps->drv_file++;
}
else if(STps->eof == ST_EOD_1) {
 STps->eof = ST_EOD_2;
 STps->drv_block =0;
if(STps->drv_file >=0)
 STps->drv_file++;
}
else if(STps->eof == ST_EOD_2)
 STps->eof = ST_EOD;
}
else if(STps->eof == ST_FM)
 STps->eof = ST_NOEOF;

return total;
}


\f
/* Set the driver options */
static void
st_log_options(Scsi_Tape *STp, ST_mode *STm,int dev)
{
printk(KERN_INFO
"st%d: Mode %d options: buffer writes: %d, async writes: %d, read ahead: %d\n",
 dev, STp->current_mode, STm->do_buffer_writes, STm->do_async_writes,
 STm->do_read_ahead);
printk(KERN_INFO
"st%d: can bsr: %d, two FMs: %d, fast mteom: %d, auto lock: %d,\n",
 dev, STp->can_bsr, STp->two_fm, STp->fast_mteom, STp->do_auto_lock);
printk(KERN_INFO
"st%d: defs for wr: %d, no block limits: %d, partitions: %d, s2 log: %d\n",
 dev, STm->defaults_for_writes, STp->omit_blklims, STp->can_partitions,
 STp->scsi2_logical);
printk(KERN_INFO
"st%d: sysv: %d\n", dev, STm->sysv);
#if DEBUG
printk(KERN_INFO
"st%d: debugging: %d\n",
 dev, debugging);
#endif
}


static int
st_set_options(struct inode * inode,long options)
{
int value;
long code;
 Scsi_Tape *STp;
 ST_mode *STm;
int dev =TAPE_NR(inode->i_rdev);

 STp = &(scsi_tapes[dev]);
 STm = &(STp->modes[STp->current_mode]);
if(!STm->defined) {
memcpy(STm, &(STp->modes[0]),sizeof(ST_mode));
 modes_defined = TRUE;
#if DEBUG
if(debugging)
printk(ST_DEB_MSG "st%d: Initialized mode %d definition from mode 0\n",
 dev, STp->current_mode);
#endif
}

 code = options & MT_ST_OPTIONS;
if(code == MT_ST_BOOLEANS) {
 STm->do_buffer_writes = (options & MT_ST_BUFFER_WRITES) !=0;
 STm->do_async_writes = (options & MT_ST_ASYNC_WRITES) !=0;
 STm->defaults_for_writes = (options & MT_ST_DEF_WRITES) !=0;
 STm->do_read_ahead = (options & MT_ST_READ_AHEAD) !=0;
 STp->two_fm = (options & MT_ST_TWO_FM) !=0;
 STp->fast_mteom = (options & MT_ST_FAST_MTEOM) !=0;
 STp->do_auto_lock = (options & MT_ST_AUTO_LOCK) !=0;
 STp->can_bsr = (options & MT_ST_CAN_BSR) !=0;
 STp->omit_blklims = (options & MT_ST_NO_BLKLIMS) !=0;
if((STp->device)->scsi_level >= SCSI_2)
 STp->can_partitions = (options & MT_ST_CAN_PARTITIONS) !=0;
 STp->scsi2_logical = (options & MT_ST_SCSI2LOGICAL) !=0;
 STm->sysv = (options & MT_ST_SYSV) !=0;
#if DEBUG
 debugging = (options & MT_ST_DEBUGGING) !=0;
#endif
st_log_options(STp, STm, dev);
}
else if(code == MT_ST_SETBOOLEANS || code == MT_ST_CLEARBOOLEANS) {
 value = (code == MT_ST_SETBOOLEANS);
if((options & MT_ST_BUFFER_WRITES) !=0)
 STm->do_buffer_writes = value;
if((options & MT_ST_ASYNC_WRITES) !=0)
 STm->do_async_writes = value;
if((options & MT_ST_DEF_WRITES) !=0)
 STm->defaults_for_writes = value;
if((options & MT_ST_READ_AHEAD) !=0)
 STm->do_read_ahead = value;
if((options & MT_ST_TWO_FM) !=0)
 STp->two_fm = value;
if((options & MT_ST_FAST_MTEOM) !=0)
 STp->fast_mteom = value;
if((options & MT_ST_AUTO_LOCK) !=0)
 STp->do_auto_lock = value;
if((options & MT_ST_CAN_BSR) !=0)
 STp->can_bsr = value;
if((options & MT_ST_NO_BLKLIMS) !=0)
 STp->omit_blklims = value;
if((STp->device)->scsi_level >= SCSI_2 &&
(options & MT_ST_CAN_PARTITIONS) !=0)
 STp->can_partitions = value;
if((options & MT_ST_SCSI2LOGICAL) !=0)
 STp->scsi2_logical = value;
if((options & MT_ST_SYSV) !=0)
 STm->sysv = value;
#if DEBUG
if((options & MT_ST_DEBUGGING) !=0)
 debugging = value;
#endif
st_log_options(STp, STm, dev);
}
else if(code == MT_ST_WRITE_THRESHOLD) {
 value = (options & ~MT_ST_OPTIONS) * ST_KILOBYTE;
if(value <1|| value > st_buffer_size) {
printk(KERN_WARNING "st%d: Write threshold %d too small or too large.\n",
 dev, value);
return(-EIO);
}
 STp->write_threshold = value;
printk(KERN_INFO "st%d: Write threshold set to %d bytes.\n",
 dev, value);
}
else if(code == MT_ST_DEF_BLKSIZE) {
 value = (options & ~MT_ST_OPTIONS);
if(value == ~MT_ST_OPTIONS) {
 STm->default_blksize = (-1);
printk(KERN_INFO "st%d: Default block size disabled.\n", dev);
}
else{
 STm->default_blksize = value;
printk(KERN_INFO "st%d: Default block size set to %d bytes.\n",
 dev, STm->default_blksize);
}
}
else if(code == MT_ST_TIMEOUTS) {
 value = (options & ~MT_ST_OPTIONS);
if((value & MT_ST_SET_LONG_TIMEOUT) !=0) {
 STp->long_timeout = (value & ~MT_ST_SET_LONG_TIMEOUT) * HZ;
printk(KERN_INFO "st%d: Long timeout set to %d seconds.\n", dev,
(value & ~MT_ST_SET_LONG_TIMEOUT));
}
else{
 STp->timeout = value * HZ;
printk(KERN_INFO "st%d: Normal timeout set to %d seconds.\n", dev,
 value);
}
}
else if(code == MT_ST_DEF_OPTIONS) {
 code = (options & ~MT_ST_CLEAR_DEFAULT);
 value = (options & MT_ST_CLEAR_DEFAULT);
if(code == MT_ST_DEF_DENSITY) {
if(value == MT_ST_CLEAR_DEFAULT) {
 STm->default_density = (-1);
printk(KERN_INFO "st%d: Density default disabled.\n", dev);
}
else{
 STm->default_density = value &0xff;
printk(KERN_INFO "st%d: Density default set to %x\n",
 dev, STm->default_density);
}
}
else if(code == MT_ST_DEF_DRVBUFFER) {
if(value == MT_ST_CLEAR_DEFAULT) {
 STp->default_drvbuffer =0xff;
printk(KERN_INFO "st%d: Drive buffer default disabled.\n", dev);
}
else{
 STp->default_drvbuffer = value &7;
printk(KERN_INFO "st%d: Drive buffer default set to %x\n",
 dev, STp->default_drvbuffer);
}
}
else if(code == MT_ST_DEF_COMPRESSION) {
if(value == MT_ST_CLEAR_DEFAULT) {
 STm->default_compression = ST_DONT_TOUCH;
printk(KERN_INFO "st%d: Compression default disabled.\n", dev);
}
else{
 STm->default_compression = (value &1? ST_YES : ST_NO);
printk(KERN_INFO "st%d: Compression default set to %x\n",
 dev, (value &1));
}
}
}
else
return(-EIO);

return0;
}

\f
#define COMPRESSION_PAGE 0x0f
#define COMPRESSION_PAGE_LENGTH 16

#define MODE_HEADER_LENGTH 4

#define DCE_MASK 0x80
#define DCC_MASK 0x40
#define RED_MASK 0x60


/* Control the compression with mode page 15. Algorithm not changed if zero. */
static int
st_compression(Scsi_Tape * STp,int state)
{
int dev;
unsigned char cmd[10];
 Scsi_Cmnd * SCpnt = NULL;

if(STp->ready != ST_READY)
return(-EIO);

/* Read the current page contents */
memset(cmd,0,10);
 cmd[0] = MODE_SENSE;
 cmd[1] =8;
 cmd[2] = COMPRESSION_PAGE;
 cmd[4] = COMPRESSION_PAGE_LENGTH + MODE_HEADER_LENGTH;

 SCpnt =st_do_scsi(SCpnt, STp, cmd, cmd[4], STp->timeout,0);
if(SCpnt == NULL)
return(-EBUSY);
 dev =TAPE_NR(SCpnt->request.rq_dev);

if((STp->buffer)->last_result_fatal !=0) {
#if DEBUG
if(debugging)
printk(ST_DEB_MSG "st%d: Compression mode page not supported.\n", dev);
#endif
scsi_release_command(SCpnt);
 SCpnt = NULL;
return(-EIO);
}
#if DEBUG
if(debugging)
printk(ST_DEB_MSG "st%d: Compression state is %d.\n", dev,
((STp->buffer)->b_data[MODE_HEADER_LENGTH +2] & DCE_MASK ?1:0));
#endif

/* Check if compression can be changed */
if(((STp->buffer)->b_data[MODE_HEADER_LENGTH +2] & DCC_MASK) ==0) {
#if DEBUG
if(debugging)
printk(ST_DEB_MSG "st%d: Compression not supported.\n", dev);
#endif
scsi_release_command(SCpnt);
 SCpnt = NULL;
return(-EIO);
}

/* Do the change */
if(state)
(STp->buffer)->b_data[MODE_HEADER_LENGTH +2] |= DCE_MASK;
else
(STp->buffer)->b_data[MODE_HEADER_LENGTH +2] &= ~DCE_MASK;

memset(cmd,0,10);
 cmd[0] = MODE_SELECT;
 cmd[1] =0x10;
 cmd[4] = COMPRESSION_PAGE_LENGTH + MODE_HEADER_LENGTH;

(STp->buffer)->b_data[0] =0;/* Reserved data length */
(STp->buffer)->b_data[1] =0;/* Reserved media type byte */
(STp->buffer)->b_data[MODE_HEADER_LENGTH] &=0x3f;
 SCpnt =st_do_scsi(SCpnt, STp, cmd, cmd[4], STp->timeout,0);

if((STp->buffer)->last_result_fatal !=0) {
#if DEBUG
if(debugging)
printk(ST_DEB_MSG "st%d: Compression change failed.\n", dev);
#endif
scsi_release_command(SCpnt);
 SCpnt = NULL;
return(-EIO);
}

#if DEBUG
if(debugging)
printk(ST_DEB_MSG "st%d: Compression state changed to %d.\n",
 dev, state);
#endif

scsi_release_command(SCpnt);
 SCpnt = NULL;
 STp->compression_changed = TRUE;
return0;
}

\f
/* Internal ioctl function */
static int
st_int_ioctl(struct inode * inode,
unsigned int cmd_in,unsigned long arg)
{
int timeout;
long ltmp;
int i, ioctl_result;
int chg_eof = TRUE;
unsigned char cmd[10];
 Scsi_Cmnd * SCpnt;
 Scsi_Tape * STp;
 ST_partstat * STps;
int fileno, blkno, at_sm, undone, datalen;
int dev =TAPE_NR(inode->i_rdev);

 STp = &(scsi_tapes[dev]);
if(STp->ready != ST_READY && cmd_in != MTLOAD) {
if(STp->ready == ST_NO_TAPE)
return(-ENOMEDIUM);
else
return(-EIO);
}
 timeout = STp->long_timeout;
 STps = &(STp->ps[STp->partition]);
 fileno = STps->drv_file;
 blkno = STps->drv_block;
 at_sm = STps->at_sm;

memset(cmd,0,10);
 datalen =0;
switch(cmd_in) {
case MTFSFM:
 chg_eof = FALSE;/* Changed from the FSF after this */
case MTFSF:
 cmd[0] = SPACE;
 cmd[1] =0x01;/* Space FileMarks */
 cmd[2] = (arg >>16);
 cmd[3] = (arg >>8);
 cmd[4] = arg;
#if DEBUG
if(debugging)
printk(ST_DEB_MSG "st%d: Spacing tape forward over %d filemarks.\n",
 dev, cmd[2] *65536+ cmd[3] *256+ cmd[4]);
#endif
if(fileno >=0)
 fileno += arg;
 blkno =0;
 at_sm &= (arg ==0);
break;
case MTBSFM:
 chg_eof = FALSE;/* Changed from the FSF after this */
case MTBSF:
 cmd[0] = SPACE;
 cmd[1] =0x01;/* Space FileMarks */
 ltmp = (-arg);
 cmd[2] = (ltmp >>16);
 cmd[3] = (ltmp >>8);
 cmd[4] = ltmp;
#if DEBUG
if(debugging) {
if(cmd[2] &0x80)
 ltmp =0xff000000;
 ltmp = ltmp | (cmd[2] <<16) | (cmd[3] <<8) | cmd[4];
printk(ST_DEB_MSG "st%d: Spacing tape backward over %ld filemarks.\n",
 dev, (-ltmp));
}
#endif
if(fileno >=0)
 fileno -= arg;
 blkno = (-1);/* We can't know the block number */
 at_sm &= (arg ==0);
break;
case MTFSR:
 cmd[0] = SPACE;
 cmd[1] =0x00;/* Space Blocks */
 cmd[2] = (arg >>16);
 cmd[3] = (arg >>8);
 cmd[4] = arg;
#if DEBUG
if(debugging)
printk(ST_DEB_MSG "st%d: Spacing tape forward %d blocks.\n", dev,
 cmd[2] *65536+ cmd[3] *256+ cmd[4]);
#endif
if(blkno >=0)
 blkno += arg;
 at_sm &= (arg ==0);
break;
case MTBSR:
 cmd[0] = SPACE;
 cmd[1] =0x00;/* Space Blocks */
 ltmp = (-arg);
 cmd[2] = (ltmp >>16);
 cmd[3] = (ltmp >>8);
 cmd[4] = ltmp;
#if DEBUG
if(debugging) {
if(cmd[2] &0x80)
 ltmp =0xff000000;
 ltmp = ltmp | (cmd[2] <<16) | (cmd[3] <<8) | cmd[4];
printk(ST_DEB_MSG "st%d: Spacing tape backward %ld blocks.\n", dev, (-ltmp));
}
#endif
if(blkno >=0)
 blkno -= arg;
 at_sm &= (arg ==0);
break;
case MTFSS:
 cmd[0] = SPACE;
 cmd[1] =0x04;/* Space Setmarks */
 cmd[2] = (arg >>16);
 cmd[3] = (arg >>8);
 cmd[4] = arg;
#if DEBUG
if(debugging)
printk(ST_DEB_MSG "st%d: Spacing tape forward %d setmarks.\n", dev,
 cmd[2] *65536+ cmd[3] *256+ cmd[4]);
#endif
if(arg !=0) {
 blkno = fileno = (-1);
 at_sm =1;
}
break;
case MTBSS:
 cmd[0] = SPACE;
 cmd[1] =0x04;/* Space Setmarks */
 ltmp = (-arg);
 cmd[2] = (ltmp >>16);
 cmd[3] = (ltmp >>8);
 cmd[4] = ltmp;
#if DEBUG
if(debugging) {
if(cmd[2] &0x80)
 ltmp =0xff000000;
 ltmp = ltmp | (cmd[2] <<16) | (cmd[3] <<8) | cmd[4];
printk(ST_DEB_MSG "st%d: Spacing tape backward %ld setmarks.\n",
 dev, (-ltmp));
}
#endif
if(arg !=0) {
 blkno = fileno = (-1);
 at_sm =1;
}
break;
case MTWEOF:
case MTWSM:
if(STp->write_prot)
return(-EACCES);
 cmd[0] = WRITE_FILEMARKS;
if(cmd_in == MTWSM)
 cmd[1] =2;
 cmd[2] = (arg >>16);
 cmd[3] = (arg >>8);
 cmd[4] = arg;
 timeout = STp->timeout;
#if DEBUG
if(debugging) {
if(cmd_in == MTWEOF)
printk(ST_DEB_MSG "st%d: Writing %d filemarks.\n", dev,
 cmd[2] *65536+ cmd[3] *256+ cmd[4]);
else
printk(ST_DEB_MSG "st%d: Writing %d setmarks.\n", dev,
 cmd[2] *65536+ cmd[3] *256+ cmd[4]);
}
#endif
if(fileno >=0)
 fileno += arg;
 blkno =0;
 at_sm = (cmd_in == MTWSM);
break;
case MTREW:
 cmd[0] = REZERO_UNIT;
#if ST_NOWAIT
 cmd[1] =1;/* Don't wait for completion */
 timeout = STp->timeout;
#endif
#if DEBUG
if(debugging)
printk(ST_DEB_MSG "st%d: Rewinding tape.\n", dev);
#endif
 fileno = blkno = at_sm =0;
break;
case MTOFFL:
case MTLOAD:
case MTUNLOAD:
 cmd[0] = START_STOP;
if(cmd_in == MTLOAD)
 cmd[4] |=1;
/*
 * If arg >= 1 && arg <= 6 Enhanced load/unload in HP C1553A
 */
if(cmd_in != MTOFFL &&
 arg >=1+ MT_ST_HPLOADER_OFFSET
&& arg <=6+ MT_ST_HPLOADER_OFFSET) {
#if DEBUG
if(debugging) {
printk(ST_DEB_MSG "st%d: Enhanced %sload slot %2ld.\n",
 dev, (cmd[4]) ?"":"un",
 arg - MT_ST_HPLOADER_OFFSET);
}
#endif
 cmd[3] = arg - MT_ST_HPLOADER_OFFSET;/* MediaID field of C1553A */
}
#if ST_NOWAIT
 cmd[1] =1;/* Don't wait for completion */
 timeout = STp->timeout;
#else
 timeout = STp->long_timeout;
#endif
#if DEBUG
if(debugging) {
if(cmd_in != MTLOAD)
printk(ST_DEB_MSG "st%d: Unloading tape.\n", dev);
else
printk(ST_DEB_MSG "st%d: Loading tape.\n", dev);
}
#endif
 fileno = blkno = at_sm =0;
break;
case MTNOP:
#if DEBUG
if(debugging)
printk(ST_DEB_MSG "st%d: No op on tape.\n", dev);
#endif
return0;/* Should do something ? */
break;
case MTRETEN:
 cmd[0] = START_STOP;
#if ST_NOWAIT
 cmd[1] =1;/* Don't wait for completion */
 timeout = STp->timeout;
#endif
 cmd[4] =3;
#if DEBUG
if(debugging)
printk(ST_DEB_MSG "st%d: Retensioning tape.\n", dev);
#endif
 fileno = blkno = at_sm =0;
break;
case MTEOM:
if(!STp->fast_mteom) {
/* space to the end of tape */
 ioctl_result =st_int_ioctl(inode, MTFSF,0x3fff);
 fileno = STps->drv_file;
if(STps->eof >= ST_EOD_1)
return0;
/* The next lines would hide the number of spaced FileMarks
 That's why I inserted the previous lines. I had no luck
 with detecting EOM with FSF, so we go now to EOM.
 Joerg Weule */
}
else
 fileno = (-1);
 cmd[0] = SPACE;
 cmd[1] =3;
#if DEBUG
if(debugging)
printk(ST_DEB_MSG "st%d: Spacing to end of recorded medium.\n", dev);
#endif
 blkno =0;
 at_sm =0;
break;
case MTERASE:
if(STp->write_prot)
return(-EACCES);
 cmd[0] = ERASE;
 cmd[1] =1;/* To the end of tape */
#if ST_NOWAIT
 cmd[1] |=2;/* Don't wait for completion */
 timeout = STp->timeout;
#else
 timeout = STp->long_timeout *8;
#endif
#if DEBUG
if(debugging)
printk(ST_DEB_MSG "st%d: Erasing tape.\n", dev);
#endif
 fileno = blkno = at_sm =0;
break;
case MTLOCK:
 chg_eof = FALSE;
 cmd[0] = ALLOW_MEDIUM_REMOVAL;
 cmd[4] = SCSI_REMOVAL_PREVENT;
#if DEBUG
if(debugging)
printk(ST_DEB_MSG "st%d: Locking drive door.\n", dev);
#endif;
break;
case MTUNLOCK:
 chg_eof = FALSE;
 cmd[0] = ALLOW_MEDIUM_REMOVAL;
 cmd[4] = SCSI_REMOVAL_ALLOW;
#if DEBUG
if(debugging)
printk(ST_DEB_MSG "st%d: Unlocking drive door.\n", dev);
#endif;
break;
case MTSETBLK:/* Set block length */
case MTSETDENSITY:/* Set tape density */
case MTSETDRVBUFFER:/* Set drive buffering */
case SET_DENS_AND_BLK:/* Set density and block size */
 chg_eof = FALSE;
if(STp->dirty || (STp->buffer)->buffer_bytes !=0)
return(-EIO);/* Not allowed if data in buffer */
if((cmd_in == MTSETBLK || cmd_in == SET_DENS_AND_BLK) &&
(arg & MT_ST_BLKSIZE_MASK) !=0&&
((arg & MT_ST_BLKSIZE_MASK) < STp->min_block ||
(arg & MT_ST_BLKSIZE_MASK) > STp->max_block ||
(arg & MT_ST_BLKSIZE_MASK) > st_buffer_size)) {
printk(KERN_WARNING "st%d: Illegal block size.\n", dev);
return(-EINVAL);
}
 cmd[0] = MODE_SELECT;
 cmd[4] = datalen =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;
 STp->density_changed = TRUE;/* At least we tried ;-) */
}
else if(cmd_in == SET_DENS_AND_BLK)
(STp->buffer)->b_data[4] = arg >>24;
else
(STp->buffer)->b_data[4] = STp->density;
if(cmd_in == MTSETBLK || cmd_in == SET_DENS_AND_BLK) {
 ltmp = arg & MT_ST_BLKSIZE_MASK;
if(cmd_in == MTSETBLK)
 STp->blksize_changed = TRUE;/* At least we tried ;-) */
}
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 = STp->timeout;
#if DEBUG
if(debugging) {
if(cmd_in == MTSETBLK || cmd_in == SET_DENS_AND_BLK)
printk(ST_DEB_MSG "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]);
if(cmd_in == MTSETDENSITY || cmd_in == SET_DENS_AND_BLK)
printk(ST_DEB_MSG "st%d: Setting density code to %x.\n", dev,
(STp->buffer)->b_data[4]);
if(cmd_in == MTSETDRVBUFFER)
printk(ST_DEB_MSG "st%d: Setting drive buffer code to %d.\n", dev,
((STp->buffer)->b_data[2] >>4) &7);
}
#endif
break;
default:
return(-ENOSYS);
}

 SCpnt =st_do_scsi(NULL, STp, cmd, datalen, timeout, MAX_RETRIES);
if(!SCpnt)
return(-EBUSY);

 ioctl_result = (STp->buffer)->last_result_fatal;

if(!ioctl_result) {/* SCSI command successful */
scsi_release_command(SCpnt);
 SCpnt = NULL;
 STps->drv_block = blkno;
 STps->drv_file = fileno;
 STps->at_sm = at_sm;

if(cmd_in == MTLOCK)
 STp->door_locked = ST_LOCKED_EXPLICIT;
else if(cmd_in == MTUNLOCK)
 STp->door_locked = ST_UNLOCKED;

if(cmd_in == MTBSFM)
 ioctl_result =st_int_ioctl(inode, MTFSF,1);
else if(cmd_in == MTFSFM)
 ioctl_result =st_int_ioctl(inode, MTBSF,1);

if(cmd_in == MTSETBLK || cmd_in == SET_DENS_AND_BLK) {
 STp->block_size = arg & MT_ST_BLKSIZE_MASK;
if(STp->block_size !=0)
(STp->buffer)->buffer_blocks =
(STp->buffer)->buffer_size / STp->block_size;
(STp->buffer)->buffer_bytes = (STp->buffer)->read_pointer =0;
if(cmd_in == SET_DENS_AND_BLK)
 STp->density = arg >> MT_ST_DENSITY_SHIFT;
}
else if(cmd_in == MTSETDRVBUFFER)
 STp->drv_buffer = (arg &7);
else if(cmd_in == MTSETDENSITY)
 STp->density = arg;

if(cmd_in == MTEOM)
 STps->eof = ST_EOD;
else if(cmd_in == MTFSF)
 STps->eof = ST_FM;
else if(chg_eof)
 STps->eof = ST_NOEOF;


if(cmd_in == MTOFFL || cmd_in == MTUNLOAD)
 STp->rew_at_close =0;
else if(cmd_in == MTLOAD) {
 STp->rew_at_close = (MINOR(inode->i_rdev) &0x80) ==0;
for(i=0; i < ST_NBR_PARTITIONS; i++) {
 STp->ps[i].rw = ST_IDLE;
 STp->ps[i].last_block_valid = FALSE;
}
 STp->partition =0;
}

}else{/* SCSI command was not completely successful. Don't return
 from this block without releasing the SCSI command block! */

if(SCpnt->sense_buffer[2] &0x40) {
if(cmd_in != MTBSF && cmd_in != MTBSFM &&
 cmd_in != MTBSR && cmd_in != MTBSS)
 STps->eof = ST_EOM_OK;
 STps->drv_block =0;
}

 undone = (
(SCpnt->sense_buffer[3] <<24) +
(SCpnt->sense_buffer[4] <<16) +
(SCpnt->sense_buffer[5] <<8) +
 SCpnt->sense_buffer[6] );
if(cmd_in == MTWEOF &&
(SCpnt->sense_buffer[0] &0x70) ==0x70&&
(SCpnt->sense_buffer[2] &0x4f) ==0x40&&
((SCpnt->sense_buffer[0] &0x80) ==0|| undone ==0)) {
 ioctl_result =0;/* EOF written succesfully at EOM */
if(fileno >=0)
 fileno++;
 STps->drv_file = fileno;
 STps->eof = ST_NOEOF;
}
else if( (cmd_in == MTFSF) || (cmd_in == MTFSFM) ) {
if(fileno >=0)
 STps->drv_file = fileno - undone ;
else
 STps->drv_file = fileno;
 STps->drv_block =0;
 STps->eof = ST_NOEOF;
}
else if( (cmd_in == MTBSF) || (cmd_in == MTBSFM) ) {
if(fileno >=0)
 STps->drv_file = fileno + undone ;
else
 STps->drv_file = fileno;
 STps->drv_block =0;
 STps->eof = ST_NOEOF;
}
else if(cmd_in == MTFSR) {
if(SCpnt->sense_buffer[2] &0x80) {/* Hit filemark */
if(STps->drv_file >=0)
 STps->drv_file++;
 STps->drv_block =0;
 STps->eof = ST_FM;
}
else{
if(blkno >= undone)
 STps->drv_block = blkno - undone;
else
 STps->drv_block = (-1);
 STps->eof = ST_NOEOF;
}
}
else if(cmd_in == MTBSR) {
if(SCpnt->sense_buffer[2] &0x80) {/* Hit filemark */
 STps->drv_file--;
 STps->drv_block = (-1);
}
else{
if(blkno >=0)
 STps->drv_block = blkno + undone;
else
 STps->drv_block = (-1);
}
 STps->eof = ST_NOEOF;
}
else if(cmd_in == MTEOM) {
 STps->drv_file = (-1);
 STps->drv_block = (-1);
 STps->eof = ST_EOD;
}
else if(chg_eof)
 STps->eof = ST_NOEOF;

if((SCpnt->sense_buffer[2] &0x0f) == BLANK_CHECK)
 STps->eof = ST_EOD;

if(cmd_in == MTLOCK)
 STp->door_locked = ST_LOCK_FAILS;

scsi_release_command(SCpnt);
 SCpnt = NULL;
}

return ioctl_result;
}


\f/* Get the tape position. If bt == 2, arg points into a kernel space mt_loc
 structure. */

static int
get_location(struct inode * inode,unsigned int*block,int*partition,
int logical)
{
 Scsi_Tape *STp;
int dev =TAPE_NR(inode->i_rdev);
int result;
unsigned char scmd[10];
 Scsi_Cmnd *SCpnt;

 STp = &(scsi_tapes[dev]);
if(STp->ready != ST_READY)
return(-EIO);

memset(scmd,0,10);
if((STp->device)->scsi_level < SCSI_2) {
 scmd[0] = QFA_REQUEST_BLOCK;
 scmd[4] =3;
}
else{
 scmd[0] = READ_POSITION;
if(!logical && !STp->scsi2_logical)
 scmd[1] =1;
}
 SCpnt =st_do_scsi(NULL, STp, scmd,20, STp->timeout, MAX_READY_RETRIES);
if(!SCpnt)
return(-EBUSY);

if((STp->buffer)->last_result_fatal !=0||
(STp->device->scsi_level >= SCSI_2 &&
((STp->buffer)->b_data[0] &4) !=0)) {
*block = *partition =0;
#if DEBUG
if(debugging)
printk(ST_DEB_MSG "st%d: Can't read tape position.\n", dev);
#endif
 result = (-EIO);
}
else{
 result =0;
if((STp->device)->scsi_level < SCSI_2) {
*block = ((STp->buffer)->b_data[0] <<16)
+ ((STp->buffer)->b_data[1] <<8)
+ (STp->buffer)->b_data[2];
*partition =0;
}
else{
*block = ((STp->buffer)->b_data[4] <<24)
+ ((STp->buffer)->b_data[5] <<16)
+ ((STp->buffer)->b_data[6] <<8)
+ (STp->buffer)->b_data[7];
*partition = (STp->buffer)->b_data[1];
if(((STp->buffer)->b_data[0] &0x80) &&
(STp->buffer)->b_data[1] ==0)/* BOP of partition 0 */
 STp->ps[0].drv_block = STp->ps[0].drv_file =0;
}
#if DEBUG
if(debugging)
printk(ST_DEB_MSG "st%d: Got tape pos. blk %d part %d.\n", dev,
*block, *partition);
#endif

}
scsi_release_command(SCpnt);
 SCpnt = NULL;

return result;
}


/* Set the tape block and partition. Negative partition means that only the
 block should be set in vendor specific way. */
static int
set_location(struct inode * inode,unsigned int block,int partition,
int logical)
{
 Scsi_Tape *STp;
 ST_partstat *STps;
int dev =TAPE_NR(inode->i_rdev);
int result, p;
unsigned int blk;
int timeout;
unsigned char scmd[10];
 Scsi_Cmnd *SCpnt;

 STp = &(scsi_tapes[dev]);
if(STp->ready != ST_READY)
return(-EIO);
 timeout = STp->long_timeout;
 STps = &(STp->ps[STp->partition]);

#if DEBUG
if(debugging)
printk(ST_DEB_MSG "st%d: Setting block to %d and partition to %d.\n",
 dev, block, partition);
if(partition <0)
return(-EIO);
#endif

/* Update the location at the partition we are leaving */
if((!STp->can_partitions && partition !=0) ||
 partition >= ST_NBR_PARTITIONS)
return(-EINVAL);
if(partition != STp->partition) {
if(get_location(inode, &blk, &p,1))
 STps->last_block_valid = FALSE;
else{
 STps->last_block_valid = TRUE;
 STps->last_block_visited = blk;
#if DEBUG
if(debugging)
printk(ST_DEB_MSG "st%d: Visited block %d for partition %d saved.\n",
 dev, blk, STp->partition);
#endif
}
}

memset(scmd,0,10);
if((STp->device)->scsi_level < SCSI_2) {
 scmd[0] = QFA_SEEK_BLOCK;
 scmd[2] = (block >>16);
 scmd[3] = (block >>8);
 scmd[4] = block;
 scmd[5] =0;
}
else{
 scmd[0] = SEEK_10;
 scmd[3] = (block >>24);
 scmd[4] = (block >>16);
 scmd[5] = (block >>8);
 scmd[6] = block;
if(!logical && !STp->scsi2_logical)
 scmd[1] =4;
if(STp->partition != partition) {
 scmd[1] |=2;
 scmd[8] = partition;
#if DEBUG
if(debugging)
printk(ST_DEB_MSG "st%d: Trying to change partition from %d to %d\n",
 dev, STp->partition, partition);
#endif
}
}
#if ST_NOWAIT
 scmd[1] |=1;/* Don't wait for completion */
 timeout = STp->timeout;
#endif

 SCpnt =st_do_scsi(NULL, STp, scmd,20, timeout, MAX_READY_RETRIES);
if(!SCpnt)
return(-EBUSY);

 STps->drv_block = STps->drv_file = (-1);
 STps->eof = ST_NOEOF;
if((STp->buffer)->last_result_fatal !=0) {
 result = (-EIO);
if(STp->can_partitions &&
(STp->device)->scsi_level >= SCSI_2 &&
(p =find_partition(inode)) >=0)
 STp->partition = p;
}
else{
if(STp->can_partitions) {
 STp->partition = partition;
 STps = &(STp->ps[partition]);
if(!STps->last_block_valid ||
 STps->last_block_visited != block) {
 STps->at_sm =0;
 STps->rw = ST_IDLE;
}
}
else
 STps->at_sm =0;
if(block ==0)
 STps->drv_block = STps->drv_file =0;
 result =0;
}

scsi_release_command(SCpnt);
 SCpnt = NULL;

return result;
}


/* Find the current partition number for the drive status. Called from open and
 returns either partition number of negative error code. */
static int
find_partition(struct inode *inode)
{
int i, partition;
unsigned int block;

if((i =get_location(inode, &block, &partition,1)) <0)
return i;
if(partition >= ST_NBR_PARTITIONS)
return(-EIO);
return partition;
}


/* Change the partition if necessary */
static int
update_partition(struct inode * inode)
{
int dev =TAPE_NR(inode->i_rdev);
 Scsi_Tape *STp;
 ST_partstat *STps;

 STp = &(scsi_tapes[dev]);
if(STp->partition == STp->new_partition)
return0;
 STps = &(STp->ps[STp->new_partition]);
if(!STps->last_block_valid)
 STps->last_block_visited =0;
returnset_location(inode, STps->last_block_visited, STp->new_partition,1);
}

\f/* Functions for reading and writing the medium partition mode page. These
 seem to work with Wangtek 6200HS and HP C1533A. */

#define PART_PAGE 0x11
#define PART_PAGE_LENGTH 10

/* Get the number of partitions on the tape. As a side effect reads the
 mode page into the tape buffer. */
static int
nbr_partitions(struct inode * inode)
{
int dev =TAPE_NR(inode->i_rdev), result;
 Scsi_Tape *STp;
 Scsi_Cmnd * SCpnt = NULL;
unsigned char cmd[10];

 STp = &(scsi_tapes[dev]);
if(STp->ready != ST_READY)
return(-EIO);

memset((void*) &cmd[0],0,10);
 cmd[0] = MODE_SENSE;
 cmd[1] =8;/* Page format */
 cmd[2] = PART_PAGE;
 cmd[4] =200;

 SCpnt =st_do_scsi(SCpnt, STp, cmd,200, STp->timeout, MAX_READY_RETRIES);
if(SCpnt == NULL)
return(-EBUSY);
scsi_release_command(SCpnt);
 SCpnt = NULL;

if((STp->buffer)->last_result_fatal !=0) {
#if DEBUG
if(debugging)
printk(ST_DEB_MSG "st%d: Can't read medium partition page.\n", dev);
#endif
 result = (-EIO);
}
else{
 result = (STp->buffer)->b_data[MODE_HEADER_LENGTH +3] +1;
#if DEBUG
if(debugging)
printk(ST_DEB_MSG "st%d: Number of partitions %d.\n", dev, result);
#endif
}

return result;
}


/* Partition the tape into two partitions if size > 0 or one partition if
 size == 0 */
static int
partition_tape(struct inode * inode,int size)
{
int dev =TAPE_NR(inode->i_rdev), result;
int length;
 Scsi_Tape *STp;
 Scsi_Cmnd * SCpnt = NULL;
unsigned char cmd[10], *bp;

if((result =nbr_partitions(inode)) <0)
return result;
 STp = &(scsi_tapes[dev]);

/* The mode page is in the buffer. Let's modify it and write it. */
 bp = &((STp->buffer)->b_data[0]);
if(size <=0) {
 length =8;
 bp[MODE_HEADER_LENGTH +3] =0;
#if DEBUG
if(debugging)
printk(ST_DEB_MSG "st%d: Formatting tape with one partition.\n", dev);
#endif
}
else{
 length =10;
 bp[MODE_HEADER_LENGTH +3] =1;
 bp[MODE_HEADER_LENGTH +8] = (size >>8) &0xff;
 bp[MODE_HEADER_LENGTH +9] = size &0xff;
#if DEBUG
if(debugging)
printk(ST_DEB_MSG "st%d: Formatting tape with two partition (1 = %d MB).\n",
 dev, size);
#endif
}
 bp[MODE_HEADER_LENGTH +6] =0;
 bp[MODE_HEADER_LENGTH +7] =0;
 bp[MODE_HEADER_LENGTH +4] =0x30;/* IDP | PSUM = MB */

 bp[0] =0;
 bp[1] =0;
 bp[MODE_HEADER_LENGTH] &=0x3f;
 bp[MODE_HEADER_LENGTH +1] = length -2;

memset(cmd,0,10);
 cmd[0] = MODE_SELECT;
 cmd[1] =0x10;
 cmd[4] = length + MODE_HEADER_LENGTH;

 SCpnt =st_do_scsi(SCpnt, STp, cmd, cmd[4], STp->long_timeout, MAX_READY_RETRIES);
if(SCpnt == NULL)
return(-EBUSY);
scsi_release_command(SCpnt);
 SCpnt = NULL;

if((STp->buffer)->last_result_fatal !=0) {
printk(KERN_INFO "st%d: Partitioning of tape failed.\n", dev);
 result = (-EIO);
}
else
 result =0;

return result;
}


\f
/* The ioctl command */
static int
st_ioctl(struct inode * inode,struct file * file,
unsigned int cmd_in,unsigned long arg)
{
int i, cmd_nr, cmd_type, bt;
unsigned int blk;
struct mtop mtc;
struct mtpos mt_pos;
 Scsi_Tape *STp;
 ST_mode *STm;
 ST_partstat *STps;
int dev =TAPE_NR(inode->i_rdev);

 STp = &(scsi_tapes[dev]);
#if DEBUG
if(debugging && !STp->in_use) {
printk(ST_DEB_MSG "st%d: Incorrect device.\n", dev);
return(-EIO);
}
#endif
 STm = &(STp->modes[STp->current_mode]);
 STps = &(STp->ps[STp->partition]);

/*
 * If we are in the middle of error recovery, don't let anyone
 * else try and use this device. Also, if error recovery fails, it
 * may try and take the device offline, in which case all further
 * access to the device is prohibited.
 */
if( !scsi_block_when_processing_errors(STp->device) )
{
return-ENXIO;
}

 cmd_type =_IOC_TYPE(cmd_in);
 cmd_nr =_IOC_NR(cmd_in);

if(cmd_type ==_IOC_TYPE(MTIOCTOP) && cmd_nr ==_IOC_NR(MTIOCTOP)) {
if(_IOC_SIZE(cmd_in) !=sizeof(mtc))
return(-EINVAL);

 i =copy_from_user((char*) &mtc, (char*)arg,sizeof(struct mtop));
if(i)
return(-EFAULT);

if(mtc.mt_op == MTSETDRVBUFFER && !suser()) {
printk(KERN_WARNING "st%d: MTSETDRVBUFFER only allowed for root.\n", dev);
return(-EPERM);
}
if(!STm->defined &&
(mtc.mt_op != MTSETDRVBUFFER && (mtc.mt_count & MT_ST_OPTIONS) ==0))
return(-ENXIO);

if(!(STp->device)->was_reset) {

if(STps->eof == ST_FM_HIT) {
if(mtc.mt_op == MTFSF || mtc.mt_op == MTFSFM|| mtc.mt_op == MTEOM) {
 mtc.mt_count -=1;
if(STps->drv_file >=0)
 STps->drv_file +=1;
}
else if(mtc.mt_op == MTBSF || mtc.mt_op == MTBSFM) {
 mtc.mt_count +=1;
if(STps->drv_file >=0)
 STps->drv_file +=1;
}
}

if(mtc.mt_op == MTSEEK) {
/* Old position must be restored if partition will be changed */
 i = !STp->can_partitions ||
(STp->new_partition != STp->partition);
}
else{
 i = mtc.mt_op == MTREW || mtc.mt_op == MTOFFL ||
 mtc.mt_op == MTRETEN || mtc.mt_op == MTEOM ||
 mtc.mt_op == MTLOCK || mtc.mt_op == MTLOAD ||
 mtc.mt_op == MTCOMPRESSION;
}
 i =flush_buffer(inode, file, i);
if(i <0)
return i;
}
else{
/*
 * If there was a bus reset, block further access
 * to this device. If the user wants to rewind the tape,
 * then reset the flag and allow access again.
 */
if(mtc.mt_op != MTREW &&
 mtc.mt_op != MTOFFL &&
 mtc.mt_op != MTRETEN &&
 mtc.mt_op != MTERASE &&
 mtc.mt_op != MTSEEK &&
 mtc.mt_op != MTEOM)
return(-EIO);
 STp->device->was_reset =0;
if(STp->door_locked != ST_UNLOCKED &&
 STp->door_locked != ST_LOCK_FAILS) {
if(st_int_ioctl(inode, MTLOCK,0)) {
printk(KERN_NOTICE "st%d: Could not relock door after bus reset.\n",
 dev);
 STp->door_locked = ST_UNLOCKED;
}
}
}

if(mtc.mt_op != MTNOP && mtc.mt_op != MTSETBLK &&
 mtc.mt_op != MTSETDENSITY && mtc.mt_op != MTWSM &&
 mtc.mt_op != MTSETDRVBUFFER && mtc.mt_op != MTSETPART)
 STps->rw = ST_IDLE;/* Prevent automatic WEOF and fsf */

if(mtc.mt_op == MTOFFL && STp->door_locked != ST_UNLOCKED)
st_int_ioctl(inode, MTUNLOCK,0);/* Ignore result! */

if(mtc.mt_op == MTSETDRVBUFFER &&
(mtc.mt_count & MT_ST_OPTIONS) !=0)
returnst_set_options(inode, mtc.mt_count);
if(mtc.mt_op == MTSETPART) {
if(!STp->can_partitions ||
 mtc.mt_count <0|| mtc.mt_count >= ST_NBR_PARTITIONS)
return(-EINVAL);
if(mtc.mt_count >= STp->nbr_partitions &&
(STp->nbr_partitions =nbr_partitions(inode)) <0)
return(-EIO);
if(mtc.mt_count >= STp->nbr_partitions)
return(-EINVAL);
 STp->new_partition = mtc.mt_count;
return0;
}
if(mtc.mt_op == MTMKPART) {
if(!STp->can_partitions)
return(-EINVAL);
if((i =st_int_ioctl(inode, MTREW,0)) <0||
(i =partition_tape(inode, mtc.mt_count)) <0)
return i;
for(i=0; i < ST_NBR_PARTITIONS; i++) {
 STp->ps[i].rw = ST_IDLE;
 STp->ps[i].at_sm =0;
 STp->ps[i].last_block_valid = FALSE;
}
 STp->partition = STp->new_partition =0;
 STp->nbr_partitions =1;/* Bad guess ?-) */
 STps->drv_block = STps->drv_file =0;
return0;
}
if(mtc.mt_op == MTSEEK) {
 i =set_location(inode, mtc.mt_count, STp->new_partition,0);
if(!STp->can_partitions)
 STp->ps[0].rw = ST_IDLE;
return i;
}
if(STp->can_partitions && STp->ready == ST_READY &&
(i =update_partition(inode)) <0)
return i;
if(mtc.mt_op == MTCOMPRESSION)
returnst_compression(STp, (mtc.mt_count &1));
else
returnst_int_ioctl(inode, mtc.mt_op, mtc.mt_count);
}

if(!STm->defined)
return(-ENXIO);

if((i =flush_buffer(inode, file, FALSE)) <0)
return i;
if(STp->can_partitions &&
(i =update_partition(inode)) <0)
return i;

if(cmd_type ==_IOC_TYPE(MTIOCGET) && cmd_nr ==_IOC_NR(MTIOCGET)) {

if(_IOC_SIZE(cmd_in) !=sizeof(struct mtget))
return(-EINVAL);

(STp->mt_status)->mt_dsreg =
((STp->block_size << MT_ST_BLKSIZE_SHIFT) & MT_ST_BLKSIZE_MASK) |
((STp->density << MT_ST_DENSITY_SHIFT) & MT_ST_DENSITY_MASK);
(STp->mt_status)->mt_blkno = STps->drv_block;
(STp->mt_status)->mt_fileno = STps->drv_file;
if(STp->block_size !=0) {
if(STps->rw == ST_WRITING)
(STp->mt_status)->mt_blkno +=
(STp->buffer)->buffer_bytes / STp->block_size;
else if(STps->rw == ST_READING)
(STp->mt_status)->mt_blkno -= ((STp->buffer)->buffer_bytes +
 STp->block_size -1) / STp->block_size;
}

(STp->mt_status)->mt_gstat =0;
if(STp->drv_write_prot)
(STp->mt_status)->mt_gstat |=GMT_WR_PROT(0xffffffff);
if((STp->mt_status)->mt_blkno ==0) {
if((STp->mt_status)->mt_fileno ==0)
(STp->mt_status)->mt_gstat |=GMT_BOT(0xffffffff);
else
(STp->mt_status)->mt_gstat |=GMT_EOF(0xffffffff);
}
(STp->mt_status)->mt_resid = STp->partition;
if(STps->eof == ST_EOM_OK || STps->eof == ST_EOM_ERROR)
(STp->mt_status)->mt_gstat |=GMT_EOT(0xffffffff);
else if(STps->eof >= ST_EOM_OK)
(STp->mt_status)->mt_gstat |=GMT_EOD(0xffffffff);
if(STp->density ==1)
(STp->mt_status)->mt_gstat |=GMT_D_800(0xffffffff);
else if(STp->density ==2)
(STp->mt_status)->mt_gstat |=GMT_D_1600(0xffffffff);
else if(STp->density ==3)
(STp->mt_status)->mt_gstat |=GMT_D_6250(0xffffffff);
if(STp->ready == ST_READY)
(STp->mt_status)->mt_gstat |=GMT_ONLINE(0xffffffff);
if(STp->ready == ST_NO_TAPE)
(STp->mt_status)->mt_gstat |=GMT_DR_OPEN(0xffffffff);
if(STps->at_sm)
(STp->mt_status)->mt_gstat |=GMT_SM(0xffffffff);
if(STm->do_async_writes || (STm->do_buffer_writes && STp->block_size !=0) ||
 STp->drv_buffer !=0)
(STp->mt_status)->mt_gstat |=GMT_IM_REP_EN(0xffffffff);

 i =copy_to_user((char*)arg, (char*)(STp->mt_status),
sizeof(struct mtget));
if(i)
return(-EFAULT);

(STp->mt_status)->mt_erreg =0;/* Clear after read */
return0;
}/* End of MTIOCGET */

if(cmd_type ==_IOC_TYPE(MTIOCPOS) && cmd_nr ==_IOC_NR(MTIOCPOS)) {
if(_IOC_SIZE(cmd_in) !=sizeof(struct mtpos))
return(-EINVAL);
if((i =get_location(inode, &blk, &bt,0)) <0)
return i;
 mt_pos.mt_blkno = blk;
 i =copy_to_user((char*)arg, (char*) (&mt_pos),sizeof(struct mtpos));
if(i)
return(-EFAULT);
return0;
}

returnscsi_ioctl(STp->device, cmd_in, (void*) arg);
}

\f
/* Try to allocate a new tape buffer */
static ST_buffer *
new_tape_buffer(int from_initialization,int need_dma )
{
int priority, a_size;
 ST_buffer *tb;

if(st_nbr_buffers >= st_template.dev_max)
return NULL;/* Should never happen */

if(from_initialization) {
 priority = GFP_ATOMIC;
 a_size = st_buffer_size;
}
else{
 priority = GFP_KERNEL;
for(a_size = PAGE_SIZE; a_size < st_buffer_size; a_size <<=1)
;/* Make sure we allocate efficiently */
}
 tb = (ST_buffer *)scsi_init_malloc(sizeof(ST_buffer), priority);
if(tb) {
if(need_dma)
 priority |= GFP_DMA;
 tb->b_data = (unsigned char*)scsi_init_malloc(a_size, priority);
if(!tb->b_data) {
scsi_init_free((char*)tb,sizeof(ST_buffer));
 tb = NULL;
}
}
if(!tb) {
printk(KERN_NOTICE "st: Can't allocate new tape buffer (nbr %d).\n",
 st_nbr_buffers);
return NULL;
}
#if DEBUG
if(debugging)
printk(ST_DEB_MSG
"st: Allocated tape buffer %d (%d bytes, dma: %d, a: %p).\n",
 st_nbr_buffers, a_size, need_dma, tb->b_data);
#endif
 tb->in_use =0;
 tb->dma = need_dma;
 tb->buffer_size = a_size;
 tb->writing =0;
 tb->orig_b_data = NULL;
 st_buffers[st_nbr_buffers++] = tb;
return tb;
}


/* Try to allocate a temporary enlarged tape buffer */
static int
enlarge_buffer(ST_buffer *STbuffer,int new_size,int need_dma)
{
int a_size, priority;
unsigned char*tbd;

normalize_buffer(STbuffer);

for(a_size = PAGE_SIZE; a_size < new_size; a_size <<=1)
;/* Make sure that we allocate efficiently */

 priority = GFP_KERNEL;
if(need_dma)
 priority |= GFP_DMA;
 tbd = (unsigned char*)scsi_init_malloc(a_size, priority);
if(!tbd)
return FALSE;
#if DEBUG
if(debugging)
printk(ST_DEB_MSG
"st: Buffer at %p enlarged to %d bytes (dma: %d, a: %p).\n",
 STbuffer->b_data, a_size, need_dma, tbd);
#endif

 STbuffer->orig_b_data = STbuffer->b_data;
 STbuffer->orig_size = STbuffer->buffer_size;
 STbuffer->b_data = tbd;
 STbuffer->buffer_size = a_size;
return TRUE;
}


/* Release the extra buffer */
static void
normalize_buffer(ST_buffer *STbuffer)
{
if(STbuffer->orig_b_data == NULL)
return;

scsi_init_free(STbuffer->b_data, STbuffer->buffer_size);
 STbuffer->b_data = STbuffer->orig_b_data;
 STbuffer->orig_b_data = NULL;
 STbuffer->buffer_size = STbuffer->orig_size;

#if DEBUG
if(debugging)
printk(ST_DEB_MSG "st: Buffer at %p normalized to %d bytes.\n",
 STbuffer->b_data, STbuffer->buffer_size);
#endif
}


#ifndef MODULE
/* Set the boot options. Syntax: st=xxx,yyy
 where xxx is buffer size in 1024 byte blocks and yyy is write threshold
 in 1024 byte blocks. */
__initfunc(void
st_setup(char*str,int*ints))
{
if(ints[0] >0&& ints[1] >0)
 st_buffer_size = ints[1] * ST_KILOBYTE;
if(ints[0] >1&& ints[2] >0) {
 st_write_threshold = ints[2] * ST_KILOBYTE;
if(st_write_threshold > st_buffer_size)
 st_write_threshold = st_buffer_size;
}
if(ints[0] >2&& ints[3] >0)
 st_max_buffers = ints[3];
}
#endif


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 */
};

static intst_attach(Scsi_Device * SDp){
 Scsi_Tape * tpnt;
 ST_mode * STm;
 ST_partstat * STps;
int i;

if(SDp->type != TYPE_TAPE)return1;

if(st_template.nr_dev >= st_template.dev_max)
{
 SDp->attached--;
return1;
}

for(tpnt = scsi_tapes, i=0; i<st_template.dev_max; i++, tpnt++)
if(!tpnt->device)break;

if(i >= st_template.dev_max)panic("scsi_devices corrupt (st)");

 scsi_tapes[i].device = SDp;
if(SDp->scsi_level <=2)
 scsi_tapes[i].mt_status->mt_type = MT_ISSCSI1;
else
 scsi_tapes[i].mt_status->mt_type = MT_ISSCSI2;

 tpnt->devt =MKDEV(SCSI_TAPE_MAJOR, i);
 tpnt->dirty =0;
 tpnt->waiting = NULL;
 tpnt->in_use =0;
 tpnt->drv_buffer =1;/* Try buffering if no mode sense */
 tpnt->restr_dma = (SDp->host)->unchecked_isa_dma;
 tpnt->density =0;
 tpnt->do_auto_lock = ST_AUTO_LOCK;
 tpnt->can_bsr = ST_IN_FILE_POS;
 tpnt->can_partitions =0;
 tpnt->two_fm = ST_TWO_FM;
 tpnt->fast_mteom = ST_FAST_MTEOM;
 tpnt->scsi2_logical = ST_SCSI2LOGICAL;
 tpnt->write_threshold = st_write_threshold;
 tpnt->default_drvbuffer =0xff;/* No forced buffering */
 tpnt->partition =0;
 tpnt->new_partition =0;
 tpnt->nbr_partitions =0;
 tpnt->timeout = ST_TIMEOUT;
 tpnt->long_timeout = ST_LONG_TIMEOUT;

for(i=0; i < ST_NBR_MODES; i++) {
 STm = &(tpnt->modes[i]);
 STm->defined = FALSE;
 STm->sysv = ST_SYSV;
 STm->defaults_for_writes =0;
 STm->do_async_writes = ST_ASYNC_WRITES;
 STm->do_buffer_writes = ST_BUFFER_WRITES;
 STm->do_read_ahead = ST_READ_AHEAD;
 STm->default_compression = ST_DONT_TOUCH;
 STm->default_blksize = (-1);/* No forced size */
 STm->default_density = (-1);/* No forced density */
}

for(i=0; i < ST_NBR_PARTITIONS; i++) {
 STps = &(tpnt->ps[i]);
 STps->rw = ST_IDLE;
 STps->eof = ST_NOEOF;
 STps->at_sm =0;
 STps->last_block_valid = FALSE;
 STps->drv_block =0;
 STps->drv_file =0;
}

 tpnt->current_mode =0;
 tpnt->modes[0].defined = TRUE;

 tpnt->density_changed = tpnt->compression_changed =
 tpnt->blksize_changed = FALSE;

 st_template.nr_dev++;
return0;
};

static intst_detect(Scsi_Device * SDp)
{
if(SDp->type != TYPE_TAPE)return0;

printk(KERN_INFO
"Detected scsi tape st%d at scsi%d, channel %d, id %d, lun %d\n",
 st_template.dev_noticed++,
 SDp->host->host_no, SDp->channel, SDp->id, SDp->lun);

return1;
}

static int st_registered =0;

/* Driver initialization (not __initfunc because may be called later) */
static intst_init()
{
int i;
 Scsi_Tape * STp;
#if !ST_RUNTIME_BUFFERS
int target_nbr;
#endif

if(st_template.dev_noticed ==0)return0;

if(!st_registered) {
if(register_chrdev(SCSI_TAPE_MAJOR,"st",&st_fops)) {
printk(KERN_ERR "Unable to get major %d for SCSI tapes\n",MAJOR_NR);
return1;
}
 st_registered++;
}

if(scsi_tapes)return0;
 st_template.dev_max = st_template.dev_noticed + ST_EXTRA_DEVS;
if(st_template.dev_max < ST_MAX_TAPES)
 st_template.dev_max = ST_MAX_TAPES;
if(st_template.dev_max >128/ ST_NBR_MODES)
printk(KERN_INFO "st: Only %d tapes accessible.\n",128/ ST_NBR_MODES);
 scsi_tapes =
(Scsi_Tape *)scsi_init_malloc(st_template.dev_max *sizeof(Scsi_Tape),
 GFP_ATOMIC);
if(scsi_tapes == NULL) {
printk(KERN_ERR "Unable to allocate descriptors for SCSI tapes.\n");
unregister_chrdev(SCSI_TAPE_MAJOR,"st");
return1;
}

#if DEBUG
printk(ST_DEB_MSG "st: Buffer size %d bytes, write threshold %d bytes.\n",
 st_buffer_size, st_write_threshold);
#endif

memset(scsi_tapes,0, st_template.dev_max *sizeof(Scsi_Tape));
for(i=0; i < st_template.dev_max; ++i) {
 STp = &(scsi_tapes[i]);
 STp->capacity =0xfffff;
 STp->mt_status = (struct mtget *)scsi_init_malloc(sizeof(struct mtget),
 GFP_ATOMIC);
/* Initialize status */
memset((void*) scsi_tapes[i].mt_status,0,sizeof(struct mtget));
}

/* Allocate the buffers */
 st_buffers =
(ST_buffer **)scsi_init_malloc(st_template.dev_max *sizeof(ST_buffer *),
 GFP_ATOMIC);
if(st_buffers == NULL) {
printk(KERN_ERR "Unable to allocate tape buffer pointers.\n");
unregister_chrdev(SCSI_TAPE_MAJOR,"st");
scsi_init_free((char*) scsi_tapes,
 st_template.dev_max *sizeof(Scsi_Tape));
return1;
}

#if ST_RUNTIME_BUFFERS
 st_nbr_buffers =0;
#else
 target_nbr = st_template.dev_noticed;
if(target_nbr < ST_EXTRA_DEVS)
 target_nbr = ST_EXTRA_DEVS;
if(target_nbr > st_max_buffers)
 target_nbr = st_max_buffers;

for(i=st_nbr_buffers=0; i < target_nbr; i++) {
if(!new_tape_buffer(TRUE, TRUE)) {
if(i ==0) {
#if 0
printk(KERN_ERR "Can't continue without at least one tape buffer.\n");
unregister_chrdev(SCSI_TAPE_MAJOR,"st");
scsi_init_free((char*) st_buffers,
 st_template.dev_max *sizeof(ST_buffer *));
scsi_init_free((char*) scsi_tapes,
 st_template.dev_max *sizeof(Scsi_Tape));
return1;
#else
printk(KERN_INFO "No tape buffers allocated at initialization.\n");
break;
#endif
}
printk(KERN_INFO "Number of tape buffers adjusted.\n");
break;
}
}
#endif
return0;
}

static voidst_detach(Scsi_Device * SDp)
{
 Scsi_Tape * tpnt;
int i;

for(tpnt = scsi_tapes, i=0; i<st_template.dev_max; i++, tpnt++)
if(tpnt->device == SDp) {
 tpnt->device = NULL;
 SDp->attached--;
 st_template.nr_dev--;
 st_template.dev_noticed--;
return;
}
return;
}


#ifdef MODULE

intinit_module(void) {
int result;

 st_template.module = &__this_module;
 result =scsi_register_module(MODULE_SCSI_DEV, &st_template);
if(result)
return result;

if(buffer_kbs >0)
 st_buffer_size = buffer_kbs * ST_KILOBYTE;
if(write_threshold_kbs >0)
 st_write_threshold = write_threshold_kbs * ST_KILOBYTE;
if(st_write_threshold > st_buffer_size)
 st_write_threshold = st_buffer_size;
if(max_buffers >0)
 st_max_buffers = max_buffers;
printk(KERN_INFO "st: bufsize %d, wrt %d, max buffers %d.\n",
st_buffer_size, st_write_threshold, st_max_buffers);

return0;
}

voidcleanup_module(void)
{
int i;

scsi_unregister_module(MODULE_SCSI_DEV, &st_template);
unregister_chrdev(SCSI_TAPE_MAJOR,"st");
 st_registered--;
if(scsi_tapes != NULL) {
scsi_init_free((char*) scsi_tapes,
 st_template.dev_max *sizeof(Scsi_Tape));

if(st_buffers != NULL) {
for(i=0; i < st_nbr_buffers; i++)
if(st_buffers[i] != NULL) {
scsi_init_free((char*) st_buffers[i]->b_data,
 st_buffers[i]->buffer_size);
scsi_init_free((char*) st_buffers[i],sizeof(ST_buffer));
}

scsi_init_free((char*) st_buffers,
 st_template.dev_max *sizeof(ST_buffer *));
}
}
 st_template.dev_max =0;
printk(KERN_INFO "st: Unloaded.\n");
}
#endif/* MODULE */