Re: [PATCH] remove ide-scsi

Bartlomiej Zolnierkiewicz
2008-12-06T14:54:44Z

On Saturday 06 December 2008, Pete Zaitcev wrote:
> On Wed, 03 Dec 2008 09:09:00 -0600, James Bottomley <James.Bottomley@HansenPartnership.com> wrote:
>
> > git log tells me ide-scsi has been updated quite a bit recently, but it
> > mostly looks to be fallout around the drivers/ide churn. Can we get ide
> > maintainer's buy in for this (I think they've been maintaining ide-tape
> > and ide-cd in preference to ide-scsi)?
>
> They must be bonkers to do it. I fixed a couple of bugs in ide-tape
> and it was one of the worst drivers I worked on, ever (worse than
> floppy.c, I kid you not). It definitely must die before ide-scsi.
> Fortunately, I solved this issue by hooking my tape to USB bridge,
> or else I'd be up in arms and wanting Tomo's blood.

Pete, I don't mean any disrespect or to deny your credit for your past
contributions but it must have been "quite a some" time ago since you were
last working on ide-tape. ;-)

[ To be sure I checked both Linus' tree (which goes back to Apr 2005,
2.6.12 timeframe) and Thomas' historical git tree (Feb 2002 / 2.4.1)
-- I don't see any IDE changes from you there. ]

In the recent years Borislav and me put substantial work into putting
ide-tape into a sane state (mainly as a by-product of working on generic
ATAPI support) and although many improvements are still possible (BTW
patches are always warmly welcomed) it doesn't contain any horrors like
idescsi_eh_abort() / idescsi_eh_reset() in ide-scsi. Moreover ide-tape
is of much less complexity than SCSI st driver (afterall ide-tape.c is
now almost half of the size / lines of code of st.c).

See for yourself, ide-tape.c from Linus' tree:

/*
* IDE ATAPI streaming tape driver.
*
* Copyright (C) 1995-1999 Gadi Oxman <gadio@netvision.net.il>
* Copyright (C) 2003-2005 Bartlomiej Zolnierkiewicz
*
* This driver was constructed as a student project in the software laboratory
* of the faculty of electrical engineering in the Technion - Israel's
* Institute Of Technology, with the guide of Avner Lottem and Dr. Ilana David.
*
* It is hereby placed under the terms of the GNU general public license.
* (See linux/COPYING).
*
* For a historical changelog see
* Documentation/ide/ChangeLog.ide-tape.1995-2002
*/

#define DRV_NAME "ide-tape"

#define IDETAPE_VERSION "1.20"

#include <linux/module.h>
#include <linux/types.h>
#include <linux/string.h>
#include <linux/kernel.h>
#include <linux/delay.h>
#include <linux/timer.h>
#include <linux/mm.h>
#include <linux/interrupt.h>
#include <linux/jiffies.h>
#include <linux/major.h>
#include <linux/errno.h>
#include <linux/genhd.h>
#include <linux/slab.h>
#include <linux/pci.h>
#include <linux/ide.h>
#include <linux/smp_lock.h>
#include <linux/completion.h>
#include <linux/bitops.h>
#include <linux/mutex.h>
#include <scsi/scsi.h>

#include <asm/byteorder.h>
#include <linux/irq.h>
#include <linux/uaccess.h>
#include <linux/io.h>
#include <asm/unaligned.h>
#include <linux/mtio.h>

enum {
/* output errors only */
DBG_ERR = (1 << 0),
/* output all sense key/asc */
DBG_SENSE = (1 << 1),
/* info regarding all chrdev-related procedures */
DBG_CHRDEV = (1 << 2),
/* all remaining procedures */
DBG_PROCS = (1 << 3),
};

/* define to see debug info */
#define IDETAPE_DEBUG_LOG 0

#if IDETAPE_DEBUG_LOG
#define debug_log(lvl, fmt, args...) \
{ \
if (tape->debug_mask & lvl) \
printk(KERN_INFO "ide-tape: " fmt, ## args); \
}
#else
#define debug_log(lvl, fmt, args...) do {} while (0)
#endif

/**************************** Tunable parameters *****************************/
/*
* After each failed packet command we issue a request sense command and retry
* the packet command IDETAPE_MAX_PC_RETRIES times.
*
* Setting IDETAPE_MAX_PC_RETRIES to 0 will disable retries.
*/
#define IDETAPE_MAX_PC_RETRIES 3

/*
* The following parameter is used to select the point in the internal tape fifo
* in which we will start to refill the buffer. Decreasing the following
* parameter will improve the system's latency and interactive response, while
* using a high value might improve system throughput.
*/
#define IDETAPE_FIFO_THRESHOLD 2

/*
* DSC polling parameters.
*
* Polling for DSC (a single bit in the status register) is a very important
* function in ide-tape. There are two cases in which we poll for DSC:
*
* 1. Before a read/write packet command, to ensure that we can transfer data
* from/to the tape's data buffers, without causing an actual media access.
* In case the tape is not ready yet, we take out our request from the device
* request queue, so that ide.c could service requests from the other device
* on the same interface in the meantime.
*
* 2. After the successful initialization of a "media access packet command",
* which is a command that can take a long time to complete (the interval can
* range from several seconds to even an hour). Again, we postpone our request
* in the middle to free the bus for the other device. The polling frequency
* here should be lower than the read/write frequency since those media access
* commands are slow. We start from a "fast" frequency - IDETAPE_DSC_MA_FAST
* (1 second), and if we don't receive DSC after IDETAPE_DSC_MA_THRESHOLD
* (5 min), we switch it to a lower frequency - IDETAPE_DSC_MA_SLOW (1 min).
*
* We also set a timeout for the timer, in case something goes wrong. The
* timeout should be longer then the maximum execution time of a tape operation.
*/

/* DSC timings. */
#define IDETAPE_DSC_RW_MIN 5*HZ/100 /* 50 msec */
#define IDETAPE_DSC_RW_MAX 40*HZ/100 /* 400 msec */
#define IDETAPE_DSC_RW_TIMEOUT 2*60*HZ /* 2 minutes */
#define IDETAPE_DSC_MA_FAST 2*HZ /* 2 seconds */
#define IDETAPE_DSC_MA_THRESHOLD 5*60*HZ /* 5 minutes */
#define IDETAPE_DSC_MA_SLOW 30*HZ /* 30 seconds */
#define IDETAPE_DSC_MA_TIMEOUT 2*60*60*HZ /* 2 hours */

/*************************** End of tunable parameters ***********************/

/* tape directions */
enum {
IDETAPE_DIR_NONE = (1 << 0),
IDETAPE_DIR_READ = (1 << 1),
IDETAPE_DIR_WRITE = (1 << 2),
};

struct idetape_bh {
u32 b_size;
atomic_t b_count;
struct idetape_bh *b_reqnext;
char *b_data;
};

/* Tape door status */
#define DOOR_UNLOCKED 0
#define DOOR_LOCKED 1
#define DOOR_EXPLICITLY_LOCKED 2

/* Some defines for the SPACE command */
#define IDETAPE_SPACE_OVER_FILEMARK 1
#define IDETAPE_SPACE_TO_EOD 3

/* Some defines for the LOAD UNLOAD command */
#define IDETAPE_LU_LOAD_MASK 1
#define IDETAPE_LU_RETENSION_MASK 2
#define IDETAPE_LU_EOT_MASK 4

/* Error codes returned in rq->errors to the higher part of the driver. */
#define IDETAPE_ERROR_GENERAL 101
#define IDETAPE_ERROR_FILEMARK 102
#define IDETAPE_ERROR_EOD 103

/* Structures related to the SELECT SENSE / MODE SENSE packet commands. */
#define IDETAPE_BLOCK_DESCRIPTOR 0
#define IDETAPE_CAPABILITIES_PAGE 0x2a

/*
* Most of our global data which we need to save even as we leave the driver due
* to an interrupt or a timer event is stored in the struct defined below.
*/
typedef struct ide_tape_obj {
ide_drive_t *drive;
ide_driver_t *driver;
struct gendisk *disk;
struct kref kref;

/*
* failed_pc points to the last failed packet command, or contains
* NULL if we do not need to retry any packet command. This is
* required since an additional packet command is needed before the
* retry, to get detailed information on what went wrong.
*/
/* Last failed packet command */
struct ide_atapi_pc *failed_pc;
/* used by REQ_IDETAPE_{READ,WRITE} requests */
struct ide_atapi_pc queued_pc;

/*
* DSC polling variables.
*
* While polling for DSC we use postponed_rq to postpone the current
* request so that ide.c will be able to service pending requests on the
* other device. Note that at most we will have only one DSC (usually
* data transfer) request in the device request queue.
*/
struct request *postponed_rq;
/* The time in which we started polling for DSC */
unsigned long dsc_polling_start;
/* Timer used to poll for dsc */
struct timer_list dsc_timer;
/* Read/Write dsc polling frequency */
unsigned long best_dsc_rw_freq;
unsigned long dsc_poll_freq;
unsigned long dsc_timeout;

/* Read position information */
u8 partition;
/* Current block */
unsigned int first_frame;

/* Last error information */
u8 sense_key, asc, ascq;

/* Character device operation */
unsigned int minor;
/* device name */
char name[4];
/* Current character device data transfer direction */
u8 chrdev_dir;

/* tape block size, usually 512 or 1024 bytes */
unsigned short blk_size;
int user_bs_factor;

/* Copy of the tape's Capabilities and Mechanical Page */
u8 caps[20];

/*
* Active data transfer request parameters.
*
* At most, there is only one ide-tape originated data transfer request
* in the device request queue. This allows ide.c to easily service
* requests from the other device when we postpone our active request.
*/

/* Data buffer size chosen based on the tape's recommendation */
int buffer_size;
/* merge buffer */
struct idetape_bh *merge_bh;
/* size of the merge buffer */
int merge_bh_size;
/* pointer to current buffer head within the merge buffer */
struct idetape_bh *bh;
char *b_data;
int b_count;

int pages_per_buffer;
/* Wasted space in each stage */
int excess_bh_size;

/* protects the ide-tape queue */
spinlock_t lock;

/* Measures average tape speed */
unsigned long avg_time;
int avg_size;
int avg_speed;

/* the door is currently locked */
int door_locked;
/* the tape hardware is write protected */
char drv_write_prot;
/* the tape is write protected (hardware or opened as read-only) */
char write_prot;

u32 debug_mask;
} idetape_tape_t;

static DEFINE_MUTEX(idetape_ref_mutex);

static struct class *idetape_sysfs_class;

static void ide_tape_release(struct kref *);

static struct ide_tape_obj *ide_tape_get(struct gendisk *disk)
{
struct ide_tape_obj *tape = NULL;

mutex_lock(&idetape_ref_mutex);
tape = ide_drv_g(disk, ide_tape_obj);
if (tape) {
if (ide_device_get(tape->drive))
tape = NULL;
else
kref_get(&tape->kref);
}
mutex_unlock(&idetape_ref_mutex);
return tape;
}

static void ide_tape_put(struct ide_tape_obj *tape)
{
ide_drive_t *drive = tape->drive;

mutex_lock(&idetape_ref_mutex);
kref_put(&tape->kref, ide_tape_release);
ide_device_put(drive);
mutex_unlock(&idetape_ref_mutex);
}

/*
* The variables below are used for the character device interface. Additional
* state variables are defined in our ide_drive_t structure.
*/
static struct ide_tape_obj *idetape_devs[MAX_HWIFS * MAX_DRIVES];

static struct ide_tape_obj *ide_tape_chrdev_get(unsigned int i)
{
struct ide_tape_obj *tape = NULL;

mutex_lock(&idetape_ref_mutex);
tape = idetape_devs[i];
if (tape)
kref_get(&tape->kref);
mutex_unlock(&idetape_ref_mutex);
return tape;
}

static void idetape_input_buffers(ide_drive_t *drive, struct ide_atapi_pc *pc,
unsigned int bcount)
{
struct idetape_bh *bh = pc->bh;
int count;

while (bcount) {
if (bh == NULL) {
printk(KERN_ERR "ide-tape: bh == NULL in "
"idetape_input_buffers\n");
ide_pad_transfer(drive, 0, bcount);
return;
}
count = min(
(unsigned int)(bh->b_size - atomic_read(&bh->b_count)),
bcount);
drive->hwif->tp_ops->input_data(drive, NULL, bh->b_data +
atomic_read(&bh->b_count), count);
bcount -= count;
atomic_add(count, &bh->b_count);
if (atomic_read(&bh->b_count) == bh->b_size) {
bh = bh->b_reqnext;
if (bh)
atomic_set(&bh->b_count, 0);
}
}
pc->bh = bh;
}

static void idetape_output_buffers(ide_drive_t *drive, struct ide_atapi_pc *pc,
unsigned int bcount)
{
struct idetape_bh *bh = pc->bh;
int count;

while (bcount) {
if (bh == NULL) {
printk(KERN_ERR "ide-tape: bh == NULL in %s\n",
__func__);
return;
}
count = min((unsigned int)pc->b_count, (unsigned int)bcount);
drive->hwif->tp_ops->output_data(drive, NULL, pc->b_data, count);
bcount -= count;
pc->b_data += count;
pc->b_count -= count;
if (!pc->b_count) {
bh = bh->b_reqnext;
pc->bh = bh;
if (bh) {
pc->b_data = bh->b_data;
pc->b_count = atomic_read(&bh->b_count);
}
}
}
}

static void idetape_update_buffers(ide_drive_t *drive, struct ide_atapi_pc *pc)
{
struct idetape_bh *bh = pc->bh;
int count;
unsigned int bcount = pc->xferred;

if (pc->flags & PC_FLAG_WRITING)
return;
while (bcount) {
if (bh == NULL) {
printk(KERN_ERR "ide-tape: bh == NULL in %s\n",
__func__);
return;
}
count = min((unsigned int)bh->b_size, (unsigned int)bcount);
atomic_set(&bh->b_count, count);
if (atomic_read(&bh->b_count) == bh->b_size)
bh = bh->b_reqnext;
bcount -= count;
}
pc->bh = bh;
}

/*
* called on each failed packet command retry to analyze the request sense. We
* currently do not utilize this information.
*/
static void idetape_analyze_error(ide_drive_t *drive, u8 *sense)
{
idetape_tape_t *tape = drive->driver_data;
struct ide_atapi_pc *pc = tape->failed_pc;

tape->sense_key = sense[2] & 0xF;
tape->asc = sense[12];
tape->ascq = sense[13];

debug_log(DBG_ERR, "pc = %x, sense key = %x, asc = %x, ascq = %x\n",
pc->c[0], tape->sense_key, tape->asc, tape->ascq);

/* Correct pc->xferred by asking the tape. */
if (pc->flags & PC_FLAG_DMA_ERROR) {
pc->xferred = pc->req_xfer -
tape->blk_size *
get_unaligned_be32(&sense[3]);
idetape_update_buffers(drive, pc);
}

/*
* If error was the result of a zero-length read or write command,
* with sense key=5, asc=0x22, ascq=0, let it slide. Some drives
* (i.e. Seagate STT3401A Travan) don't support 0-length read/writes.
*/
if ((pc->c[0] == READ_6 || pc->c[0] == WRITE_6)
/* length == 0 */
&& pc->c[4] == 0 && pc->c[3] == 0 && pc->c[2] == 0) {
if (tape->sense_key == 5) {
/* don't report an error, everything's ok */
pc->error = 0;
/* don't retry read/write */
pc->flags |= PC_FLAG_ABORT;
}
}
if (pc->c[0] == READ_6 && (sense[2] & 0x80)) {
pc->error = IDETAPE_ERROR_FILEMARK;
pc->flags |= PC_FLAG_ABORT;
}
if (pc->c[0] == WRITE_6) {
if ((sense[2] & 0x40) || (tape->sense_key == 0xd
&& tape->asc == 0x0 && tape->ascq == 0x2)) {
pc->error = IDETAPE_ERROR_EOD;
pc->flags |= PC_FLAG_ABORT;
}
}
if (pc->c[0] == READ_6 || pc->c[0] == WRITE_6) {
if (tape->sense_key == 8) {
pc->error = IDETAPE_ERROR_EOD;
pc->flags |= PC_FLAG_ABORT;
}
if (!(pc->flags & PC_FLAG_ABORT) &&
pc->xferred)
pc->retries = IDETAPE_MAX_PC_RETRIES + 1;
}
}

/* Free data buffers completely. */
static void ide_tape_kfree_buffer(idetape_tape_t *tape)
{
struct idetape_bh *prev_bh, *bh = tape->merge_bh;

while (bh) {
u32 size = bh->b_size;

while (size) {
unsigned int order = fls(size >> PAGE_SHIFT)-1;

if (bh->b_data)
free_pages((unsigned long)bh->b_data, order);

size &= (order-1);
bh->b_data += (1 << order) * PAGE_SIZE;
}
prev_bh = bh;
bh = bh->b_reqnext;
kfree(prev_bh);
}
}

static int idetape_end_request(ide_drive_t *drive, int uptodate, int nr_sects)
{
struct request *rq = HWGROUP(drive)->rq;
idetape_tape_t *tape = drive->driver_data;
unsigned long flags;
int error;

debug_log(DBG_PROCS, "Enter %s\n", __func__);

switch (uptodate) {
case 0: error = IDETAPE_ERROR_GENERAL; break;
case 1: error = 0; break;
default: error = uptodate;
}
rq->errors = error;
if (error)
tape->failed_pc = NULL;

if (!blk_special_request(rq)) {
ide_end_request(drive, uptodate, nr_sects);
return 0;
}

spin_lock_irqsave(&tape->lock, flags);

ide_end_drive_cmd(drive, 0, 0);

spin_unlock_irqrestore(&tape->lock, flags);
return 0;
}

static void ide_tape_handle_dsc(ide_drive_t *);

static void ide_tape_callback(ide_drive_t *drive, int dsc)
{
idetape_tape_t *tape = drive->driver_data;
struct ide_atapi_pc *pc = drive->pc;
int uptodate = pc->error ? 0 : 1;

debug_log(DBG_PROCS, "Enter %s\n", __func__);

if (dsc)
ide_tape_handle_dsc(drive);

if (tape->failed_pc == pc)
tape->failed_pc = NULL;

if (pc->c[0] == REQUEST_SENSE) {
if (uptodate)
idetape_analyze_error(drive, pc->buf);
else
printk(KERN_ERR "ide-tape: Error in REQUEST SENSE "
"itself - Aborting request!\n");
} else if (pc->c[0] == READ_6 || pc->c[0] == WRITE_6) {
struct request *rq = drive->hwif->hwgroup->rq;
int blocks = pc->xferred / tape->blk_size;

tape->avg_size += blocks * tape->blk_size;

if (time_after_eq(jiffies, tape->avg_time + HZ)) {
tape->avg_speed = tape->avg_size * HZ /
(jiffies - tape->avg_time) / 1024;
tape->avg_size = 0;
tape->avg_time = jiffies;
}

tape->first_frame += blocks;
rq->current_nr_sectors -= blocks;

if (pc->error)
uptodate = pc->error;
} else if (pc->c[0] == READ_POSITION && uptodate) {
u8 *readpos = pc->buf;

debug_log(DBG_SENSE, "BOP - %s\n",
(readpos[0] & 0x80) ? "Yes" : "No");
debug_log(DBG_SENSE, "EOP - %s\n",
(readpos[0] & 0x40) ? "Yes" : "No");

if (readpos[0] & 0x4) {
printk(KERN_INFO "ide-tape: Block location is unknown"
"to the tape\n");
clear_bit(IDE_AFLAG_ADDRESS_VALID, &drive->atapi_flags);
uptodate = 0;
} else {
debug_log(DBG_SENSE, "Block Location - %u\n",
be32_to_cpup((__be32 *)&readpos[4]));

tape->partition = readpos[1];
tape->first_frame = be32_to_cpup((__be32 *)&readpos[4]);
set_bit(IDE_AFLAG_ADDRESS_VALID, &drive->atapi_flags);
}
}

idetape_end_request(drive, uptodate, 0);
}

/*
* Postpone the current request so that ide.c will be able to service requests
* from another device on the same hwgroup while we are polling for DSC.
*/
static void idetape_postpone_request(ide_drive_t *drive)
{
idetape_tape_t *tape = drive->driver_data;

debug_log(DBG_PROCS, "Enter %s\n", __func__);

tape->postponed_rq = HWGROUP(drive)->rq;
ide_stall_queue(drive, tape->dsc_poll_freq);
}

static void ide_tape_handle_dsc(ide_drive_t *drive)
{
idetape_tape_t *tape = drive->driver_data;

/* Media access command */
tape->dsc_polling_start = jiffies;
tape->dsc_poll_freq = IDETAPE_DSC_MA_FAST;
tape->dsc_timeout = jiffies + IDETAPE_DSC_MA_TIMEOUT;
/* Allow ide.c to handle other requests */
idetape_postpone_request(drive);
}

static int ide_tape_io_buffers(ide_drive_t *drive, struct ide_atapi_pc *pc,
unsigned int bcount, int write)
{
if (write)
idetape_output_buffers(drive, pc, bcount);
else
idetape_input_buffers(drive, pc, bcount);

return bcount;
}

/*
* Packet Command Interface
*
* The current Packet Command is available in drive->pc, and will not change
* until we finish handling it. Each packet command is associated with a
* callback function that will be called when the command is finished.
*
* The handling will be done in three stages:
*
* 1. idetape_issue_pc will send the packet command to the drive, and will set
* the interrupt handler to ide_pc_intr.
*
* 2. On each interrupt, ide_pc_intr will be called. This step will be
* repeated until the device signals us that no more interrupts will be issued.
*
* 3. ATAPI Tape media access commands have immediate status with a delayed
* process. In case of a successful initiation of a media access packet command,
* the DSC bit will be set when the actual execution of the command is finished.
* Since the tape drive will not issue an interrupt, we have to poll for this
* event. In this case, we define the request as "low priority request" by
* setting rq_status to IDETAPE_RQ_POSTPONED, set a timer to poll for DSC and
* exit the driver.
*
* ide.c will then give higher priority to requests which originate from the
* other device, until will change rq_status to RQ_ACTIVE.
*
* 4. When the packet command is finished, it will be checked for errors.
*
* 5. In case an error was found, we queue a request sense packet command in
* front of the request queue and retry the operation up to
* IDETAPE_MAX_PC_RETRIES times.
*
* 6. In case no error was found, or we decided to give up and not to retry
* again, the callback function will be called and then we will handle the next
* request.
*/

static ide_startstop_t idetape_issue_pc(ide_drive_t *drive,
struct ide_atapi_pc *pc)
{
idetape_tape_t *tape = drive->driver_data;

if (drive->pc->c[0] == REQUEST_SENSE &&
pc->c[0] == REQUEST_SENSE) {
printk(KERN_ERR "ide-tape: possible ide-tape.c bug - "
"Two request sense in serial were issued\n");
}

if (tape->failed_pc == NULL && pc->c[0] != REQUEST_SENSE)
tape->failed_pc = pc;

/* Set the current packet command */
drive->pc = pc;

if (pc->retries > IDETAPE_MAX_PC_RETRIES ||
(pc->flags & PC_FLAG_ABORT)) {
/*
* We will "abort" retrying a packet command in case legitimate
* error code was received (crossing a filemark, or end of the
* media, for example).
*/
if (!(pc->flags & PC_FLAG_ABORT)) {
if (!(pc->c[0] == TEST_UNIT_READY &&
tape->sense_key == 2 && tape->asc == 4 &&
(tape->ascq == 1 || tape->ascq == 8))) {
printk(KERN_ERR "ide-tape: %s: I/O error, "
"pc = %2x, key = %2x, "
"asc = %2x, ascq = %2x\n",
tape->name, pc->c[0],
tape->sense_key, tape->asc,
tape->ascq);
}
/* Giving up */
pc->error = IDETAPE_ERROR_GENERAL;
}
tape->failed_pc = NULL;
drive->pc_callback(drive, 0);
return ide_stopped;
}
debug_log(DBG_SENSE, "Retry #%d, cmd = %02X\n", pc->retries, pc->c[0]);

pc->retries++;

return ide_issue_pc(drive, WAIT_TAPE_CMD, NULL);
}

/* A mode sense command is used to "sense" tape parameters. */
static void idetape_create_mode_sense_cmd(struct ide_atapi_pc *pc, u8 page_code)
{
ide_init_pc(pc);
pc->c[0] = MODE_SENSE;
if (page_code != IDETAPE_BLOCK_DESCRIPTOR)
/* DBD = 1 - Don't return block descriptors */
pc->c[1] = 8;
pc->c[2] = page_code;
/*
* Changed pc->c[3] to 0 (255 will at best return unused info).
*
* For SCSI this byte is defined as subpage instead of high byte
* of length and some IDE drives seem to interpret it this way
* and return an error when 255 is used.
*/
pc->c[3] = 0;
/* We will just discard data in that case */
pc->c[4] = 255;
if (page_code == IDETAPE_BLOCK_DESCRIPTOR)
pc->req_xfer = 12;
else if (page_code == IDETAPE_CAPABILITIES_PAGE)
pc->req_xfer = 24;
else
pc->req_xfer = 50;
}

static ide_startstop_t idetape_media_access_finished(ide_drive_t *drive)
{
ide_hwif_t *hwif = drive->hwif;
idetape_tape_t *tape = drive->driver_data;
struct ide_atapi_pc *pc = drive->pc;
u8 stat;

stat = hwif->tp_ops->read_status(hwif);

if (stat & ATA_DSC) {
if (stat & ATA_ERR) {
/* Error detected */
if (pc->c[0] != TEST_UNIT_READY)
printk(KERN_ERR "ide-tape: %s: I/O error, ",
tape->name);
/* Retry operation */
ide_retry_pc(drive, tape->disk);
return ide_stopped;
}
pc->error = 0;
} else {
pc->error = IDETAPE_ERROR_GENERAL;
tape->failed_pc = NULL;
}
drive->pc_callback(drive, 0);
return ide_stopped;
}

static void ide_tape_create_rw_cmd(idetape_tape_t *tape,
struct ide_atapi_pc *pc, struct request *rq,
u8 opcode)
{
struct idetape_bh *bh = (struct idetape_bh *)rq->special;
unsigned int length = rq->current_nr_sectors;

ide_init_pc(pc);
put_unaligned(cpu_to_be32(length), (unsigned int *) &pc->c[1]);
pc->c[1] = 1;
pc->bh = bh;
pc->buf = NULL;
pc->buf_size = length * tape->blk_size;
pc->req_xfer = pc->buf_size;
if (pc->req_xfer == tape->buffer_size)
pc->flags |= PC_FLAG_DMA_OK;

if (opcode == READ_6) {
pc->c[0] = READ_6;
atomic_set(&bh->b_count, 0);
} else if (opcode == WRITE_6) {
pc->c[0] = WRITE_6;
pc->flags |= PC_FLAG_WRITING;
pc->b_data = bh->b_data;
pc->b_count = atomic_read(&bh->b_count);
}

memcpy(rq->cmd, pc->c, 12);
}

static ide_startstop_t idetape_do_request(ide_drive_t *drive,
struct request *rq, sector_t block)
{
ide_hwif_t *hwif = drive->hwif;
idetape_tape_t *tape = drive->driver_data;
struct ide_atapi_pc *pc = NULL;
struct request *postponed_rq = tape->postponed_rq;
u8 stat;

debug_log(DBG_SENSE, "sector: %llu, nr_sectors: %lu,"
" current_nr_sectors: %u\n",
(unsigned long long)rq->sector, rq->nr_sectors,
rq->current_nr_sectors);

if (!blk_special_request(rq)) {
/* We do not support buffer cache originated requests. */
printk(KERN_NOTICE "ide-tape: %s: Unsupported request in "
"request queue (%d)\n", drive->name, rq->cmd_type);
ide_end_request(drive, 0, 0);
return ide_stopped;
}

/* Retry a failed packet command */
if (tape->failed_pc && drive->pc->c[0] == REQUEST_SENSE) {
pc = tape->failed_pc;
goto out;
}

if (postponed_rq != NULL)
if (rq != postponed_rq) {
printk(KERN_ERR "ide-tape: ide-tape.c bug - "
"Two DSC requests were queued\n");
idetape_end_request(drive, 0, 0);
return ide_stopped;
}

tape->postponed_rq = NULL;

/*
* If the tape is still busy, postpone our request and service
* the other device meanwhile.
*/
stat = hwif->tp_ops->read_status(hwif);

if ((drive->dev_flags & IDE_DFLAG_DSC_OVERLAP) == 0 &&
(rq->cmd[13] & REQ_IDETAPE_PC2) == 0)
set_bit(IDE_AFLAG_IGNORE_DSC, &drive->atapi_flags);

if (drive->dev_flags & IDE_DFLAG_POST_RESET) {
set_bit(IDE_AFLAG_IGNORE_DSC, &drive->atapi_flags);
drive->dev_flags &= ~IDE_DFLAG_POST_RESET;
}

if (!test_and_clear_bit(IDE_AFLAG_IGNORE_DSC, &drive->atapi_flags) &&
(stat & ATA_DSC) == 0) {
if (postponed_rq == NULL) {
tape->dsc_polling_start = jiffies;
tape->dsc_poll_freq = tape->best_dsc_rw_freq;
tape->dsc_timeout = jiffies + IDETAPE_DSC_RW_TIMEOUT;
} else if (time_after(jiffies, tape->dsc_timeout)) {
printk(KERN_ERR "ide-tape: %s: DSC timeout\n",
tape->name);
if (rq->cmd[13] & REQ_IDETAPE_PC2) {
idetape_media_access_finished(drive);
return ide_stopped;
} else {
return ide_do_reset(drive);
}
} else if (time_after(jiffies,
tape->dsc_polling_start +
IDETAPE_DSC_MA_THRESHOLD))
tape->dsc_poll_freq = IDETAPE_DSC_MA_SLOW;
idetape_postpone_request(drive);
return ide_stopped;
}
if (rq->cmd[13] & REQ_IDETAPE_READ) {
pc = &tape->queued_pc;
ide_tape_create_rw_cmd(tape, pc, rq, READ_6);
goto out;
}
if (rq->cmd[13] & REQ_IDETAPE_WRITE) {
pc = &tape->queued_pc;
ide_tape_create_rw_cmd(tape, pc, rq, WRITE_6);
goto out;
}
if (rq->cmd[13] & REQ_IDETAPE_PC1) {
pc = (struct ide_atapi_pc *) rq->buffer;
rq->cmd[13] &= ~(REQ_IDETAPE_PC1);
rq->cmd[13] |= REQ_IDETAPE_PC2;
goto out;
}
if (rq->cmd[13] & REQ_IDETAPE_PC2) {
idetape_media_access_finished(drive);
return ide_stopped;
}
BUG();

out:
return idetape_issue_pc(drive, pc);
}

/*
* The function below uses __get_free_pages to allocate a data buffer of size
* tape->buffer_size (or a bit more). We attempt to combine sequential pages as
* much as possible.
*
* It returns a pointer to the newly allocated buffer, or NULL in case of
* failure.
*/
static struct idetape_bh *ide_tape_kmalloc_buffer(idetape_tape_t *tape,
int full, int clear)
{
struct idetape_bh *prev_bh, *bh, *merge_bh;
int pages = tape->pages_per_buffer;
unsigned int order, b_allocd;
char *b_data = NULL;

merge_bh = kmalloc(sizeof(struct idetape_bh), GFP_KERNEL);
bh = merge_bh;
if (bh == NULL)
goto abort;

order = fls(pages) - 1;
bh->b_data = (char *) __get_free_pages(GFP_KERNEL, order);
if (!bh->b_data)
goto abort;
b_allocd = (1 << order) * PAGE_SIZE;
pages &= (order-1);

if (clear)
memset(bh->b_data, 0, b_allocd);
bh->b_reqnext = NULL;
bh->b_size = b_allocd;
atomic_set(&bh->b_count, full ? bh->b_size : 0);

while (pages) {
order = fls(pages) - 1;
b_data = (char *) __get_free_pages(GFP_KERNEL, order);
if (!b_data)
goto abort;
b_allocd = (1 << order) * PAGE_SIZE;

if (clear)
memset(b_data, 0, b_allocd);

/* newly allocated page frames below buffer header or ...*/
if (bh->b_data == b_data + b_allocd) {
bh->b_size += b_allocd;
bh->b_data -= b_allocd;
if (full)
atomic_add(b_allocd, &bh->b_count);
continue;
}
/* they are above the header */
if (b_data == bh->b_data + bh->b_size) {
bh->b_size += b_allocd;
if (full)
atomic_add(b_allocd, &bh->b_count);
continue;
}
prev_bh = bh;
bh = kmalloc(sizeof(struct idetape_bh), GFP_KERNEL);
if (!bh) {
free_pages((unsigned long) b_data, order);
goto abort;
}
bh->b_reqnext = NULL;
bh->b_data = b_data;
bh->b_size = b_allocd;
atomic_set(&bh->b_count, full ? bh->b_size : 0);
prev_bh->b_reqnext = bh;

pages &= (order-1);
}

bh->b_size -= tape->excess_bh_size;
if (full)
atomic_sub(tape->excess_bh_size, &bh->b_count);
return merge_bh;
abort:
ide_tape_kfree_buffer(tape);
return NULL;
}

static int idetape_copy_stage_from_user(idetape_tape_t *tape,
const char __user *buf, int n)
{
struct idetape_bh *bh = tape->bh;
int count;
int ret = 0;

while (n) {
if (bh == NULL) {
printk(KERN_ERR "ide-tape: bh == NULL in %s\n",
__func__);
return 1;
}
count = min((unsigned int)
(bh->b_size - atomic_read(&bh->b_count)),
(unsigned int)n);
if (copy_from_user(bh->b_data + atomic_read(&bh->b_count), buf,
count))
ret = 1;
n -= count;
atomic_add(count, &bh->b_count);
buf += count;
if (atomic_read(&bh->b_count) == bh->b_size) {
bh = bh->b_reqnext;
if (bh)
atomic_set(&bh->b_count, 0);
}
}
tape->bh = bh;
return ret;
}

static int idetape_copy_stage_to_user(idetape_tape_t *tape, char __user *buf,
int n)
{
struct idetape_bh *bh = tape->bh;
int count;
int ret = 0;

while (n) {
if (bh == NULL) {
printk(KERN_ERR "ide-tape: bh == NULL in %s\n",
__func__);
return 1;
}
count = min(tape->b_count, n);
if (copy_to_user(buf, tape->b_data, count))
ret = 1;
n -= count;
tape->b_data += count;
tape->b_count -= count;
buf += count;
if (!tape->b_count) {
bh = bh->b_reqnext;
tape->bh = bh;
if (bh) {
tape->b_data = bh->b_data;
tape->b_count = atomic_read(&bh->b_count);
}
}
}
return ret;
}

static void idetape_init_merge_buffer(idetape_tape_t *tape)
{
struct idetape_bh *bh = tape->merge_bh;
tape->bh = tape->merge_bh;

if (tape->chrdev_dir == IDETAPE_DIR_WRITE)
atomic_set(&bh->b_count, 0);
else {
tape->b_data = bh->b_data;
tape->b_count = atomic_read(&bh->b_count);
}
}

/*
* Write a filemark if write_filemark=1. Flush the device buffers without
* writing a filemark otherwise.
*/
static void idetape_create_write_filemark_cmd(ide_drive_t *drive,
struct ide_atapi_pc *pc, int write_filemark)
{
ide_init_pc(pc);
pc->c[0] = WRITE_FILEMARKS;
pc->c[4] = write_filemark;
pc->flags |= PC_FLAG_WAIT_FOR_DSC;
}

static int idetape_wait_ready(ide_drive_t *drive, unsigned long timeout)
{
idetape_tape_t *tape = drive->driver_data;
struct gendisk *disk = tape->disk;
int load_attempted = 0;

/* Wait for the tape to become ready */
set_bit(IDE_AFLAG_MEDIUM_PRESENT, &drive->atapi_flags);
timeout += jiffies;
while (time_before(jiffies, timeout)) {
if (ide_do_test_unit_ready(drive, disk) == 0)
return 0;
if ((tape->sense_key == 2 && tape->asc == 4 && tape->ascq == 2)
|| (tape->asc == 0x3A)) {
/* no media */
if (load_attempted)
return -ENOMEDIUM;
ide_do_start_stop(drive, disk, IDETAPE_LU_LOAD_MASK);
load_attempted = 1;
/* not about to be ready */
} else if (!(tape->sense_key == 2 && tape->asc == 4 &&
(tape->ascq == 1 || tape->ascq == 8)))
return -EIO;
msleep(100);
}
return -EIO;
}

static int idetape_flush_tape_buffers(ide_drive_t *drive)
{
struct ide_tape_obj *tape = drive->driver_data;
struct ide_atapi_pc pc;
int rc;

idetape_create_write_filemark_cmd(drive, &pc, 0);
rc = ide_queue_pc_tail(drive, tape->disk, &pc);
if (rc)
return rc;
idetape_wait_ready(drive, 60 * 5 * HZ);
return 0;
}

static void idetape_create_read_position_cmd(struct ide_atapi_pc *pc)
{
ide_init_pc(pc);
pc->c[0] = READ_POSITION;
pc->req_xfer = 20;
}

static int idetape_read_position(ide_drive_t *drive)
{
idetape_tape_t *tape = drive->driver_data;
struct ide_atapi_pc pc;
int position;

debug_log(DBG_PROCS, "Enter %s\n", __func__);

idetape_create_read_position_cmd(&pc);
if (ide_queue_pc_tail(drive, tape->disk, &pc))
return -1;
position = tape->first_frame;
return position;
}

static void idetape_create_locate_cmd(ide_drive_t *drive,
struct ide_atapi_pc *pc,
unsigned int block, u8 partition, int skip)
{
ide_init_pc(pc);
pc->c[0] = POSITION_TO_ELEMENT;
pc->c[1] = 2;
put_unaligned(cpu_to_be32(block), (unsigned int *) &pc->c[3]);
pc->c[8] = partition;
pc->flags |= PC_FLAG_WAIT_FOR_DSC;
}

static void __ide_tape_discard_merge_buffer(ide_drive_t *drive)
{
idetape_tape_t *tape = drive->driver_data;

if (tape->chrdev_dir != IDETAPE_DIR_READ)
return;

clear_bit(IDE_AFLAG_FILEMARK, &drive->atapi_flags);
tape->merge_bh_size = 0;
if (tape->merge_bh != NULL) {
ide_tape_kfree_buffer(tape);
tape->merge_bh = NULL;
}

tape->chrdev_dir = IDETAPE_DIR_NONE;
}

/*
* Position the tape to the requested block using the LOCATE packet command.
* A READ POSITION command is then issued to check where we are positioned. Like
* all higher level operations, we queue the commands at the tail of the request
* queue and wait for their completion.
*/
static int idetape_position_tape(ide_drive_t *drive, unsigned int block,
u8 partition, int skip)
{
idetape_tape_t *tape = drive->driver_data;
struct gendisk *disk = tape->disk;
int retval;
struct ide_atapi_pc pc;

if (tape->chrdev_dir == IDETAPE_DIR_READ)
__ide_tape_discard_merge_buffer(drive);
idetape_wait_ready(drive, 60 * 5 * HZ);
idetape_create_locate_cmd(drive, &pc, block, partition, skip);
retval = ide_queue_pc_tail(drive, disk, &pc);
if (retval)
return (retval);

idetape_create_read_position_cmd(&pc);
return ide_queue_pc_tail(drive, disk, &pc);
}

static void ide_tape_discard_merge_buffer(ide_drive_t *drive,
int restore_position)
{
idetape_tape_t *tape = drive->driver_data;
int seek, position;

__ide_tape_discard_merge_buffer(drive);
if (restore_position) {
position = idetape_read_position(drive);
seek = position > 0 ? position : 0;
if (idetape_position_tape(drive, seek, 0, 0)) {
printk(KERN_INFO "ide-tape: %s: position_tape failed in"
" %s\n", tape->name, __func__);
return;
}
}
}

/*
* Generate a read/write request for the block device interface and wait for it
* to be serviced.
*/
static int idetape_queue_rw_tail(ide_drive_t *drive, int cmd, int blocks,
struct idetape_bh *bh)
{
idetape_tape_t *tape = drive->driver_data;
struct request *rq;
int ret, errors;

debug_log(DBG_SENSE, "%s: cmd=%d\n", __func__, cmd);

rq = blk_get_request(drive->queue, READ, __GFP_WAIT);
rq->cmd_type = REQ_TYPE_SPECIAL;
rq->cmd[13] = cmd;
rq->rq_disk = tape->disk;
rq->special = (void *)bh;
rq->sector = tape->first_frame;
rq->nr_sectors = blocks;
rq->current_nr_sectors = blocks;
blk_execute_rq(drive->queue, tape->disk, rq, 0);

errors = rq->errors;
ret = tape->blk_size * (blocks - rq->current_nr_sectors);
blk_put_request(rq);

if ((cmd & (REQ_IDETAPE_READ | REQ_IDETAPE_WRITE)) == 0)
return 0;

if (tape->merge_bh)
idetape_init_merge_buffer(tape);
if (errors == IDETAPE_ERROR_GENERAL)
return -EIO;
return ret;
}

static void idetape_create_inquiry_cmd(struct ide_atapi_pc *pc)
{
ide_init_pc(pc);
pc->c[0] = INQUIRY;
pc->c[4] = 254;
pc->req_xfer = 254;
}

static void idetape_create_rewind_cmd(ide_drive_t *drive,
struct ide_atapi_pc *pc)
{
ide_init_pc(pc);
pc->c[0] = REZERO_UNIT;
pc->flags |= PC_FLAG_WAIT_FOR_DSC;
}

static void idetape_create_erase_cmd(struct ide_atapi_pc *pc)
{
ide_init_pc(pc);
pc->c[0] = ERASE;
pc->c[1] = 1;
pc->flags |= PC_FLAG_WAIT_FOR_DSC;
}

static void idetape_create_space_cmd(struct ide_atapi_pc *pc, int count, u8 cmd)
{
ide_init_pc(pc);
pc->c[0] = SPACE;
put_unaligned(cpu_to_be32(count), (unsigned int *) &pc->c[1]);
pc->c[1] = cmd;
pc->flags |= PC_FLAG_WAIT_FOR_DSC;
}

/* Queue up a character device originated write request. */
static int idetape_add_chrdev_write_request(ide_drive_t *drive, int blocks)
{
idetape_tape_t *tape = drive->driver_data;

debug_log(DBG_CHRDEV, "Enter %s\n", __func__);

return idetape_queue_rw_tail(drive, REQ_IDETAPE_WRITE,
blocks, tape->merge_bh);
}

static void ide_tape_flush_merge_buffer(ide_drive_t *drive)
{
idetape_tape_t *tape = drive->driver_data;
int blocks, min;
struct idetape_bh *bh;

if (tape->chrdev_dir != IDETAPE_DIR_WRITE) {
printk(KERN_ERR "ide-tape: bug: Trying to empty merge buffer"
" but we are not writing.\n");
return;
}
if (tape->merge_bh_size > tape->buffer_size) {
printk(KERN_ERR "ide-tape: bug: merge_buffer too big\n");
tape->merge_bh_size = tape->buffer_size;
}
if (tape->merge_bh_size) {
blocks = tape->merge_bh_size / tape->blk_size;
if (tape->merge_bh_size % tape->blk_size) {
unsigned int i;

blocks++;
i = tape->blk_size - tape->merge_bh_size %
tape->blk_size;
bh = tape->bh->b_reqnext;
while (bh) {
atomic_set(&bh->b_count, 0);
bh = bh->b_reqnext;
}
bh = tape->bh;
while (i) {
if (bh == NULL) {
printk(KERN_INFO "ide-tape: bug,"
" bh NULL\n");
break;
}
min = min(i, (unsigned int)(bh->b_size -
atomic_read(&bh->b_count)));
memset(bh->b_data + atomic_read(&bh->b_count),
0, min);
atomic_add(min, &bh->b_count);
i -= min;
bh = bh->b_reqnext;
}
}
(void) idetape_add_chrdev_write_request(drive, blocks);
tape->merge_bh_size = 0;
}
if (tape->merge_bh != NULL) {
ide_tape_kfree_buffer(tape);
tape->merge_bh = NULL;
}
tape->chrdev_dir = IDETAPE_DIR_NONE;
}

static int idetape_init_read(ide_drive_t *drive)
{
idetape_tape_t *tape = drive->driver_data;
int bytes_read;

/* Initialize read operation */
if (tape->chrdev_dir != IDETAPE_DIR_READ) {
if (tape->chrdev_dir == IDETAPE_DIR_WRITE) {
ide_tape_flush_merge_buffer(drive);
idetape_flush_tape_buffers(drive);
}
if (tape->merge_bh || tape->merge_bh_size) {
printk(KERN_ERR "ide-tape: merge_bh_size should be"
" 0 now\n");
tape->merge_bh_size = 0;
}
tape->merge_bh = ide_tape_kmalloc_buffer(tape, 0, 0);
if (!tape->merge_bh)
return -ENOMEM;
tape->chrdev_dir = IDETAPE_DIR_READ;

/*
* Issue a read 0 command to ensure that DSC handshake is
* switched from completion mode to buffer available mode.
* No point in issuing this if DSC overlap isn't supported, some
* drives (Seagate STT3401A) will return an error.
*/
if (drive->dev_flags & IDE_DFLAG_DSC_OVERLAP) {
bytes_read = idetape_queue_rw_tail(drive,
REQ_IDETAPE_READ, 0,
tape->merge_bh);
if (bytes_read < 0) {
ide_tape_kfree_buffer(tape);
tape->merge_bh = NULL;
tape->chrdev_dir = IDETAPE_DIR_NONE;
return bytes_read;
}
}
}

return 0;
}

/* called from idetape_chrdev_read() to service a chrdev read request. */
static int idetape_add_chrdev_read_request(ide_drive_t *drive, int blocks)
{
idetape_tape_t *tape = drive->driver_data;

debug_log(DBG_PROCS, "Enter %s, %d blocks\n", __func__, blocks);

/* If we are at a filemark, return a read length of 0 */
if (test_bit(IDE_AFLAG_FILEMARK, &drive->atapi_flags))
return 0;

idetape_init_read(drive);

return idetape_queue_rw_tail(drive, REQ_IDETAPE_READ, blocks,
tape->merge_bh);
}

static void idetape_pad_zeros(ide_drive_t *drive, int bcount)
{
idetape_tape_t *tape = drive->driver_data;
struct idetape_bh *bh;
int blocks;

while (bcount) {
unsigned int count;

bh = tape->merge_bh;
count = min(tape->buffer_size, bcount);
bcount -= count;
blocks = count / tape->blk_size;
while (count) {
atomic_set(&bh->b_count,
min(count, (unsigned int)bh->b_size));
memset(bh->b_data, 0, atomic_read(&bh->b_count));
count -= atomic_read(&bh->b_count);
bh = bh->b_reqnext;
}
idetape_queue_rw_tail(drive, REQ_IDETAPE_WRITE, blocks,
tape->merge_bh);
}
}

/*
* Rewinds the tape to the Beginning Of the current Partition (BOP). We
* currently support only one partition.
*/
static int idetape_rewind_tape(ide_drive_t *drive)
{
struct ide_tape_obj *tape = drive->driver_data;
struct gendisk *disk = tape->disk;
int retval;
struct ide_atapi_pc pc;

debug_log(DBG_SENSE, "Enter %s\n", __func__);

idetape_create_rewind_cmd(drive, &pc);
retval = ide_queue_pc_tail(drive, disk, &pc);
if (retval)
return retval;

idetape_create_read_position_cmd(&pc);
retval = ide_queue_pc_tail(drive, disk, &pc);
if (retval)
return retval;
return 0;
}

/* mtio.h compatible commands should be issued to the chrdev interface. */
static int idetape_blkdev_ioctl(ide_drive_t *drive, unsigned int cmd,
unsigned long arg)
{
idetape_tape_t *tape = drive->driver_data;
void __user *argp = (void __user *)arg;

struct idetape_config {
int dsc_rw_frequency;
int dsc_media_access_frequency;
int nr_stages;
} config;

debug_log(DBG_PROCS, "Enter %s\n", __func__);

switch (cmd) {
case 0x0340:
if (copy_from_user(&config, argp, sizeof(config)))
return -EFAULT;
tape->best_dsc_rw_freq = config.dsc_rw_frequency;
break;
case 0x0350:
config.dsc_rw_frequency = (int) tape->best_dsc_rw_freq;
config.nr_stages = 1;
if (copy_to_user(argp, &config, sizeof(config)))
return -EFAULT;
break;
default:
return -EIO;
}
return 0;
}

static int idetape_space_over_filemarks(ide_drive_t *drive, short mt_op,
int mt_count)
{
idetape_tape_t *tape = drive->driver_data;
struct gendisk *disk = tape->disk;
struct ide_atapi_pc pc;
int retval, count = 0;
int sprev = !!(tape->caps[4] & 0x20);

if (mt_count == 0)
return 0;
if (MTBSF == mt_op || MTBSFM == mt_op) {
if (!sprev)
return -EIO;
mt_count = -mt_count;
}

if (tape->chrdev_dir == IDETAPE_DIR_READ) {
tape->merge_bh_size = 0;
if (test_and_clear_bit(IDE_AFLAG_FILEMARK, &drive->atapi_flags))
++count;
ide_tape_discard_merge_buffer(drive, 0);
}

switch (mt_op) {
case MTFSF:
case MTBSF:
idetape_create_space_cmd(&pc, mt_count - count,
IDETAPE_SPACE_OVER_FILEMARK);
return ide_queue_pc_tail(drive, disk, &pc);
case MTFSFM:
case MTBSFM:
if (!sprev)
return -EIO;
retval = idetape_space_over_filemarks(drive, MTFSF,
mt_count - count);
if (retval)
return retval;
count = (MTBSFM == mt_op ? 1 : -1);
return idetape_space_over_filemarks(drive, MTFSF, count);
default:
printk(KERN_ERR "ide-tape: MTIO operation %d not supported\n",
mt_op);
return -EIO;
}
}

/*
* Our character device read / write functions.
*
* The tape is optimized to maximize throughput when it is transferring an
* integral number of the "continuous transfer limit", which is a parameter of
* the specific tape (26kB on my particular tape, 32kB for Onstream).
*
* As of version 1.3 of the driver, the character device provides an abstract
* continuous view of the media - any mix of block sizes (even 1 byte) on the
* same backup/restore procedure is supported. The driver will internally
* convert the requests to the recommended transfer unit, so that an unmatch
* between the user's block size to the recommended size will only result in a
* (slightly) increased driver overhead, but will no longer hit performance.
* This is not applicable to Onstream.
*/
static ssize_t idetape_chrdev_read(struct file *file, char __user *buf,
size_t count, loff_t *ppos)
{
struct ide_tape_obj *tape = file->private_data;
ide_drive_t *drive = tape->drive;
ssize_t bytes_read, temp, actually_read = 0, rc;
ssize_t ret = 0;
u16 ctl = *(u16 *)&tape->caps[12];

debug_log(DBG_CHRDEV, "Enter %s, count %Zd\n", __func__, count);

if (tape->chrdev_dir != IDETAPE_DIR_READ) {
if (test_bit(IDE_AFLAG_DETECT_BS, &drive->atapi_flags))
if (count > tape->blk_size &&
(count % tape->blk_size) == 0)
tape->user_bs_factor = count / tape->blk_size;
}
rc = idetape_init_read(drive);
if (rc < 0)
return rc;
if (count == 0)
return (0);
if (tape->merge_bh_size) {
actually_read = min((unsigned int)(tape->merge_bh_size),
(unsigned int)count);
if (idetape_copy_stage_to_user(tape, buf, actually_read))
ret = -EFAULT;
buf += actually_read;
tape->merge_bh_size -= actually_read;
count -= actually_read;
}
while (count >= tape->buffer_size) {
bytes_read = idetape_add_chrdev_read_request(drive, ctl);
if (bytes_read <= 0)
goto finish;
if (idetape_copy_stage_to_user(tape, buf, bytes_read))
ret = -EFAULT;
buf += bytes_read;
count -= bytes_read;
actually_read += bytes_read;
}
if (count) {
bytes_read = idetape_add_chrdev_read_request(drive, ctl);
if (bytes_read <= 0)
goto finish;
temp = min((unsigned long)count, (unsigned long)bytes_read);
if (idetape_copy_stage_to_user(tape, buf, temp))
ret = -EFAULT;
actually_read += temp;
tape->merge_bh_size = bytes_read-temp;
}
finish:
if (!actually_read && test_bit(IDE_AFLAG_FILEMARK, &drive->atapi_flags)) {
debug_log(DBG_SENSE, "%s: spacing over filemark\n", tape->name);

idetape_space_over_filemarks(drive, MTFSF, 1);
return 0;
}

return ret ? ret : actually_read;
}

static ssize_t idetape_chrdev_write(struct file *file, const char __user *buf,
size_t count, loff_t *ppos)
{
struct ide_tape_obj *tape = file->private_data;
ide_drive_t *drive = tape->drive;
ssize_t actually_written = 0;
ssize_t ret = 0;
u16 ctl = *(u16 *)&tape->caps[12];

/* The drive is write protected. */
if (tape->write_prot)
return -EACCES;

debug_log(DBG_CHRDEV, "Enter %s, count %Zd\n", __func__, count);

/* Initialize write operation */
if (tape->chrdev_dir != IDETAPE_DIR_WRITE) {
if (tape->chrdev_dir == IDETAPE_DIR_READ)
ide_tape_discard_merge_buffer(drive, 1);
if (tape->merge_bh || tape->merge_bh_size) {
printk(KERN_ERR "ide-tape: merge_bh_size "
"should be 0 now\n");
tape->merge_bh_size = 0;
}
tape->merge_bh = ide_tape_kmalloc_buffer(tape, 0, 0);
if (!tape->merge_bh)
return -ENOMEM;
tape->chrdev_dir = IDETAPE_DIR_WRITE;
idetape_init_merge_buffer(tape);

/*
* Issue a write 0 command to ensure that DSC handshake is
* switched from completion mode to buffer available mode. No
* point in issuing this if DSC overlap isn't supported, some
* drives (Seagate STT3401A) will return an error.
*/
if (drive->dev_flags & IDE_DFLAG_DSC_OVERLAP) {
ssize_t retval = idetape_queue_rw_tail(drive,
REQ_IDETAPE_WRITE, 0,
tape->merge_bh);
if (retval < 0) {
ide_tape_kfree_buffer(tape);
tape->merge_bh = NULL;
tape->chrdev_dir = IDETAPE_DIR_NONE;
return retval;
}
}
}
if (count == 0)
return (0);
if (tape->merge_bh_size) {
if (tape->merge_bh_size >= tape->buffer_size) {
printk(KERN_ERR "ide-tape: bug: merge buf too big\n");
tape->merge_bh_size = 0;
}
actually_written = min((unsigned int)
(tape->buffer_size - tape->merge_bh_size),
(unsigned int)count);
if (idetape_copy_stage_from_user(tape, buf, actually_written))
ret = -EFAULT;
buf += actually_written;
tape->merge_bh_size += actually_written;
count -= actually_written;

if (tape->merge_bh_size == tape->buffer_size) {
ssize_t retval;
tape->merge_bh_size = 0;
retval = idetape_add_chrdev_write_request(drive, ctl);
if (retval <= 0)
return (retval);
}
}
while (count >= tape->buffer_size) {
ssize_t retval;
if (idetape_copy_stage_from_user(tape, buf, tape->buffer_size))
ret = -EFAULT;
buf += tape->buffer_size;
count -= tape->buffer_size;
retval = idetape_add_chrdev_write_request(drive, ctl);
actually_written += tape->buffer_size;
if (retval <= 0)
return (retval);
}
if (count) {
actually_written += count;
if (idetape_copy_stage_from_user(tape, buf, count))
ret = -EFAULT;
tape->merge_bh_size += count;
}
return ret ? ret : actually_written;
}

static int idetape_write_filemark(ide_drive_t *drive)
{
struct ide_tape_obj *tape = drive->driver_data;
struct ide_atapi_pc pc;

/* Write a filemark */
idetape_create_write_filemark_cmd(drive, &pc, 1);
if (ide_queue_pc_tail(drive, tape->disk, &pc)) {
printk(KERN_ERR "ide-tape: Couldn't write a filemark\n");
return -EIO;
}
return 0;
}

/*
* Called from idetape_chrdev_ioctl when the general mtio MTIOCTOP ioctl is
* requested.
*
* Note: MTBSF and MTBSFM are not supported when the tape doesn't support
* spacing over filemarks in the reverse direction. In this case, MTFSFM is also
* usually not supported.
*
* The following commands are currently not supported:
*
* MTFSS, MTBSS, MTWSM, MTSETDENSITY, MTSETDRVBUFFER, MT_ST_BOOLEANS,
* MT_ST_WRITE_THRESHOLD.
*/
static int idetape_mtioctop(ide_drive_t *drive, short mt_op, int mt_count)
{
idetape_tape_t *tape = drive->driver_data;
struct gendisk *disk = tape->disk;
struct ide_atapi_pc pc;
int i, retval;

debug_log(DBG_ERR, "Handling MTIOCTOP ioctl: mt_op=%d, mt_count=%d\n",
mt_op, mt_count);

switch (mt_op) {
case MTFSF:
case MTFSFM:
case MTBSF:
case MTBSFM:
if (!mt_count)
return 0;
return idetape_space_over_filemarks(drive, mt_op, mt_count);
default:
break;
}

switch (mt_op) {
case MTWEOF:
if (tape->write_prot)
return -EACCES;
ide_tape_discard_merge_buffer(drive, 1);
for (i = 0; i < mt_count; i++) {
retval = idetape_write_filemark(drive);
if (retval)
return retval;
}
return 0;
case MTREW:
ide_tape_discard_merge_buffer(drive, 0);
if (idetape_rewind_tape(drive))
return -EIO;
return 0;
case MTLOAD:
ide_tape_discard_merge_buffer(drive, 0);
return ide_do_start_stop(drive, disk, IDETAPE_LU_LOAD_MASK);
case MTUNLOAD:
case MTOFFL:
/*
* If door is locked, attempt to unlock before
* attempting to eject.
*/
if (tape->door_locked) {
if (!ide_set_media_lock(drive, disk, 0))
tape->door_locked = DOOR_UNLOCKED;
}
ide_tape_discard_merge_buffer(drive, 0);
retval = ide_do_start_stop(drive, disk, !IDETAPE_LU_LOAD_MASK);
if (!retval)
clear_bit(IDE_AFLAG_MEDIUM_PRESENT, &drive->atapi_flags);
return retval;
case MTNOP:
ide_tape_discard_merge_buffer(drive, 0);
return idetape_flush_tape_buffers(drive);
case MTRETEN:
ide_tape_discard_merge_buffer(drive, 0);
return ide_do_start_stop(drive, disk,
IDETAPE_LU_RETENSION_MASK | IDETAPE_LU_LOAD_MASK);
case MTEOM:
idetape_create_space_cmd(&pc, 0, IDETAPE_SPACE_TO_EOD);
return ide_queue_pc_tail(drive, disk, &pc);
case MTERASE:
(void)idetape_rewind_tape(drive);
idetape_create_erase_cmd(&pc);
return ide_queue_pc_tail(drive, disk, &pc);
case MTSETBLK:
if (mt_count) {
if (mt_count < tape->blk_size ||
mt_count % tape->blk_size)
return -EIO;
tape->user_bs_factor = mt_count / tape->blk_size;
clear_bit(IDE_AFLAG_DETECT_BS, &drive->atapi_flags);
} else
set_bit(IDE_AFLAG_DETECT_BS, &drive->atapi_flags);
return 0;
case MTSEEK:
ide_tape_discard_merge_buffer(drive, 0);
return idetape_position_tape(drive,
mt_count * tape->user_bs_factor, tape->partition, 0);
case MTSETPART:
ide_tape_discard_merge_buffer(drive, 0);
return idetape_position_tape(drive, 0, mt_count, 0);
case MTFSR:
case MTBSR:
case MTLOCK:
retval = ide_set_media_lock(drive, disk, 1);
if (retval)
return retval;
tape->door_locked = DOOR_EXPLICITLY_LOCKED;
return 0;
case MTUNLOCK:
retval = ide_set_media_lock(drive, disk, 0);
if (retval)
return retval;
tape->door_locked = DOOR_UNLOCKED;
return 0;
default:
printk(KERN_ERR "ide-tape: MTIO operation %d not supported\n",
mt_op);
return -EIO;
}
}

/*
* Our character device ioctls. General mtio.h magnetic io commands are
* supported here, and not in the corresponding block interface. Our own
* ide-tape ioctls are supported on both interfaces.
*/
static int idetape_chrdev_ioctl(struct inode *inode, struct file *file,
unsigned int cmd, unsigned long arg)
{
struct ide_tape_obj *tape = file->private_data;
ide_drive_t *drive = tape->drive;
struct mtop mtop;
struct mtget mtget;
struct mtpos mtpos;
int block_offset = 0, position = tape->first_frame;
void __user *argp = (void __user *)arg;

debug_log(DBG_CHRDEV, "Enter %s, cmd=%u\n", __func__, cmd);

if (tape->chrdev_dir == IDETAPE_DIR_WRITE) {
ide_tape_flush_merge_buffer(drive);
idetape_flush_tape_buffers(drive);
}
if (cmd == MTIOCGET || cmd == MTIOCPOS) {
block_offset = tape->merge_bh_size /
(tape->blk_size * tape->user_bs_factor);
position = idetape_read_position(drive);
if (position < 0)
return -EIO;
}
switch (cmd) {
case MTIOCTOP:
if (copy_from_user(&mtop, argp, sizeof(struct mtop)))
return -EFAULT;
return idetape_mtioctop(drive, mtop.mt_op, mtop.mt_count);
case MTIOCGET:
memset(&mtget, 0, sizeof(struct mtget));
mtget.mt_type = MT_ISSCSI2;
mtget.mt_blkno = position / tape->user_bs_factor - block_offset;
mtget.mt_dsreg =
((tape->blk_size * tape->user_bs_factor)
<< MT_ST_BLKSIZE_SHIFT) & MT_ST_BLKSIZE_MASK;

if (tape->drv_write_prot)
mtget.mt_gstat |= GMT_WR_PROT(0xffffffff);

if (copy_to_user(argp, &mtget, sizeof(struct mtget)))
return -EFAULT;
return 0;
case MTIOCPOS:
mtpos.mt_blkno = position / tape->user_bs_factor - block_offset;
if (copy_to_user(argp, &mtpos, sizeof(struct mtpos)))
return -EFAULT;
return 0;
default:
if (tape->chrdev_dir == IDETAPE_DIR_READ)
ide_tape_discard_merge_buffer(drive, 1);
return idetape_blkdev_ioctl(drive, cmd, arg);
}
}

/*
* Do a mode sense page 0 with block descriptor and if it succeeds set the tape
* block size with the reported value.
*/
static void ide_tape_get_bsize_from_bdesc(ide_drive_t *drive)
{
idetape_tape_t *tape = drive->driver_data;
struct ide_atapi_pc pc;

idetape_create_mode_sense_cmd(&pc, IDETAPE_BLOCK_DESCRIPTOR);
if (ide_queue_pc_tail(drive, tape->disk, &pc)) {
printk(KERN_ERR "ide-tape: Can't get block descriptor\n");
if (tape->blk_size == 0) {
printk(KERN_WARNING "ide-tape: Cannot deal with zero "
"block size, assuming 32k\n");
tape->blk_size = 32768;
}
return;
}
tape->blk_size = (pc.buf[4 + 5] << 16) +
(pc.buf[4 + 6] << 8) +
pc.buf[4 + 7];
tape->drv_write_prot = (pc.buf[2] & 0x80) >> 7;
}

static int idetape_chrdev_open(struct inode *inode, struct file *filp)
{
unsigned int minor = iminor(inode), i = minor & ~0xc0;
ide_drive_t *drive;
idetape_tape_t *tape;
int retval;

if (i >= MAX_HWIFS * MAX_DRIVES)
return -ENXIO;

lock_kernel();
tape = ide_tape_chrdev_get(i);
if (!tape) {
unlock_kernel();
return -ENXIO;
}

debug_log(DBG_CHRDEV, "Enter %s\n", __func__);

/*
* We really want to do nonseekable_open(inode, filp); here, but some
* versions of tar incorrectly call lseek on tapes and bail out if that
* fails. So we disallow pread() and pwrite(), but permit lseeks.
*/
filp->f_mode &= ~(FMODE_PREAD | FMODE_PWRITE);

drive = tape->drive;

filp->private_data = tape;

if (test_and_set_bit(IDE_AFLAG_BUSY, &drive->atapi_flags)) {
retval = -EBUSY;
goto out_put_tape;
}

retval = idetape_wait_ready(drive, 60 * HZ);
if (retval) {
clear_bit(IDE_AFLAG_BUSY, &drive->atapi_flags);
printk(KERN_ERR "ide-tape: %s: drive not ready\n", tape->name);
goto out_put_tape;
}

idetape_read_position(drive);
if (!test_bit(IDE_AFLAG_ADDRESS_VALID, &drive->atapi_flags))
(void)idetape_rewind_tape(drive);

/* Read block size and write protect status from drive. */
ide_tape_get_bsize_from_bdesc(drive);

/* Set write protect flag if device is opened as read-only. */
if ((filp->f_flags & O_ACCMODE) == O_RDONLY)
tape->write_prot = 1;
else
tape->write_prot = tape->drv_write_prot;

/* Make sure drive isn't write protected if user wants to write. */
if (tape->write_prot) {
if ((filp->f_flags & O_ACCMODE) == O_WRONLY ||
(filp->f_flags & O_ACCMODE) == O_RDWR) {
clear_bit(IDE_AFLAG_BUSY, &drive->atapi_flags);
retval = -EROFS;
goto out_put_tape;
}
}

/* Lock the tape drive door so user can't eject. */
if (tape->chrdev_dir == IDETAPE_DIR_NONE) {
if (!ide_set_media_lock(drive, tape->disk, 1)) {
if (tape->door_locked != DOOR_EXPLICITLY_LOCKED)
tape->door_locked = DOOR_LOCKED;
}
}
unlock_kernel();
return 0;

out_put_tape:
ide_tape_put(tape);
unlock_kernel();
return retval;
}

static void idetape_write_release(ide_drive_t *drive, unsigned int minor)
{
idetape_tape_t *tape = drive->driver_data;

ide_tape_flush_merge_buffer(drive);
tape->merge_bh = ide_tape_kmalloc_buffer(tape, 1, 0);
if (tape->merge_bh != NULL) {
idetape_pad_zeros(drive, tape->blk_size *
(tape->user_bs_factor - 1));
ide_tape_kfree_buffer(tape);
tape->merge_bh = NULL;
}
idetape_write_filemark(drive);
idetape_flush_tape_buffers(drive);
idetape_flush_tape_buffers(drive);
}

static int idetape_chrdev_release(struct inode *inode, struct file *filp)
{
struct ide_tape_obj *tape = filp->private_data;
ide_drive_t *drive = tape->drive;
unsigned int minor = iminor(inode);

lock_kernel();
tape = drive->driver_data;

debug_log(DBG_CHRDEV, "Enter %s\n", __func__);

if (tape->chrdev_dir == IDETAPE_DIR_WRITE)
idetape_write_release(drive, minor);
if (tape->chrdev_dir == IDETAPE_DIR_READ) {
if (minor < 128)
ide_tape_discard_merge_buffer(drive, 1);
}

if (minor < 128 && test_bit(IDE_AFLAG_MEDIUM_PRESENT, &drive->atapi_flags))
(void) idetape_rewind_tape(drive);
if (tape->chrdev_dir == IDETAPE_DIR_NONE) {
if (tape->door_locked == DOOR_LOCKED) {
if (!ide_set_media_lock(drive, tape->disk, 0))
tape->door_locked = DOOR_UNLOCKED;
}
}
clear_bit(IDE_AFLAG_BUSY, &drive->atapi_flags);
ide_tape_put(tape);
unlock_kernel();
return 0;
}

static void idetape_get_inquiry_results(ide_drive_t *drive)
{
idetape_tape_t *tape = drive->driver_data;
struct ide_atapi_pc pc;
char fw_rev[4], vendor_id[8], product_id[16];

idetape_create_inquiry_cmd(&pc);
if (ide_queue_pc_tail(drive, tape->disk, &pc)) {
printk(KERN_ERR "ide-tape: %s: can't get INQUIRY results\n",
tape->name);
return;
}
memcpy(vendor_id, &pc.buf[8], 8);
memcpy(product_id, &pc.buf[16], 16);
memcpy(fw_rev, &pc.buf[32], 4);

ide_fixstring(vendor_id, 8, 0);
ide_fixstring(product_id, 16, 0);
ide_fixstring(fw_rev, 4, 0);

printk(KERN_INFO "ide-tape: %s <-> %s: %.8s %.16s rev %.4s\n",
drive->name, tape->name, vendor_id, product_id, fw_rev);
}

/*
* Ask the tape about its various parameters. In particular, we will adjust our
* data transfer buffer size to the recommended value as returned by the tape.
*/
static void idetape_get_mode_sense_results(ide_drive_t *drive)
{
idetape_tape_t *tape = drive->driver_data;
struct ide_atapi_pc pc;
u8 *caps;
u8 speed, max_speed;

idetape_create_mode_sense_cmd(&pc, IDETAPE_CAPABILITIES_PAGE);
if (ide_queue_pc_tail(drive, tape->disk, &pc)) {
printk(KERN_ERR "ide-tape: Can't get tape parameters - assuming"
" some default values\n");
tape->blk_size = 512;
put_unaligned(52, (u16 *)&tape->caps[12]);
put_unaligned(540, (u16 *)&tape->caps[14]);
put_unaligned(6*52, (u16 *)&tape->caps[16]);
return;
}
caps = pc.buf + 4 + pc.buf[3];

/* convert to host order and save for later use */
speed = be16_to_cpup((__be16 *)&caps[14]);
max_speed = be16_to_cpup((__be16 *)&caps[8]);

*(u16 *)&caps[8] = max_speed;
*(u16 *)&caps[12] = be16_to_cpup((__be16 *)&caps[12]);
*(u16 *)&caps[14] = speed;
*(u16 *)&caps[16] = be16_to_cpup((__be16 *)&caps[16]);

if (!speed) {
printk(KERN_INFO "ide-tape: %s: invalid tape speed "
"(assuming 650KB/sec)\n", drive->name);
*(u16 *)&caps[14] = 650;
}
if (!max_speed) {
printk(KERN_INFO "ide-tape: %s: invalid max_speed "
"(assuming 650KB/sec)\n", drive->name);
*(u16 *)&caps[8] = 650;
}

memcpy(&tape->caps, caps, 20);

/* device lacks locking support according to capabilities page */
if ((caps[6] & 1) == 0)
drive->dev_flags &= ~IDE_DFLAG_DOORLOCKING;

if (caps[7] & 0x02)
tape->blk_size = 512;
else if (caps[7] & 0x04)
tape->blk_size = 1024;
}

#ifdef CONFIG_IDE_PROC_FS
#define ide_tape_devset_get(name, field) \
static int get_##name(ide_drive_t *drive) \
{ \
idetape_tape_t *tape = drive->driver_data; \
return tape->field; \
}

#define ide_tape_devset_set(name, field) \
static int set_##name(ide_drive_t *drive, int arg) \
{ \
idetape_tape_t *tape = drive->driver_data; \
tape->field = arg; \
return 0; \
}

#define ide_tape_devset_rw_field(_name, _field) \
ide_tape_devset_get(_name, _field) \
ide_tape_devset_set(_name, _field) \
IDE_DEVSET(_name, DS_SYNC, get_##_name, set_##_name)

#define ide_tape_devset_r_field(_name, _field) \
ide_tape_devset_get(_name, _field) \
IDE_DEVSET(_name, 0, get_##_name, NULL)

static int mulf_tdsc(ide_drive_t *drive) { return 1000; }
static int divf_tdsc(ide_drive_t *drive) { return HZ; }
static int divf_buffer(ide_drive_t *drive) { return 2; }
static int divf_buffer_size(ide_drive_t *drive) { return 1024; }

ide_devset_rw_flag(dsc_overlap, IDE_DFLAG_DSC_OVERLAP);

ide_tape_devset_rw_field(debug_mask, debug_mask);
ide_tape_devset_rw_field(tdsc, best_dsc_rw_freq);

ide_tape_devset_r_field(avg_speed, avg_speed);
ide_tape_devset_r_field(speed, caps[14]);
ide_tape_devset_r_field(buffer, caps[16]);
ide_tape_devset_r_field(buffer_size, buffer_size);

static const struct ide_proc_devset idetape_settings[] = {
__IDE_PROC_DEVSET(avg_speed, 0, 0xffff, NULL, NULL),
__IDE_PROC_DEVSET(buffer, 0, 0xffff, NULL, divf_buffer),
__IDE_PROC_DEVSET(buffer_size, 0, 0xffff, NULL, divf_buffer_size),
__IDE_PROC_DEVSET(debug_mask, 0, 0xffff, NULL, NULL),
__IDE_PROC_DEVSET(dsc_overlap, 0, 1, NULL, NULL),
__IDE_PROC_DEVSET(speed, 0, 0xffff, NULL, NULL),
__IDE_PROC_DEVSET(tdsc, IDETAPE_DSC_RW_MIN, IDETAPE_DSC_RW_MAX,
mulf_tdsc, divf_tdsc),
{ 0 },
};
#endif

/*
* The function below is called to:
*
* 1. Initialize our various state variables.
* 2. Ask the tape for its capabilities.
* 3. Allocate a buffer which will be used for data transfer. The buffer size
* is chosen based on the recommendation which we received in step 2.
*
* Note that at this point ide.c already assigned us an irq, so that we can
* queue requests here and wait for their completion.
*/
static void idetape_setup(ide_drive_t *drive, idetape_tape_t *tape, int minor)
{
unsigned long t;
int speed;
int buffer_size;
u16 *ctl = (u16 *)&tape->caps[12];

drive->pc_callback = ide_tape_callback;
drive->pc_update_buffers = idetape_update_buffers;
drive->pc_io_buffers = ide_tape_io_buffers;

spin_lock_init(&tape->lock);

drive->dev_flags |= IDE_DFLAG_DSC_OVERLAP;

if (drive->hwif->host_flags & IDE_HFLAG_NO_DSC) {
printk(KERN_INFO "ide-tape: %s: disabling DSC overlap\n",
tape->name);
drive->dev_flags &= ~IDE_DFLAG_DSC_OVERLAP;
}

/* Seagate Travan drives do not support DSC overlap. */
if (strstr((char *)&drive->id[ATA_ID_PROD], "Seagate STT3401"))
drive->dev_flags &= ~IDE_DFLAG_DSC_OVERLAP;

tape->minor = minor;
tape->name[0] = 'h';
tape->name[1] = 't';
tape->name[2] = '0' + minor;
tape->chrdev_dir = IDETAPE_DIR_NONE;

idetape_get_inquiry_results(drive);
idetape_get_mode_sense_results(drive);
ide_tape_get_bsize_from_bdesc(drive);
tape->user_bs_factor = 1;
tape->buffer_size = *ctl * tape->blk_size;
while (tape->buffer_size > 0xffff) {
printk(KERN_NOTICE "ide-tape: decreasing stage size\n");
*ctl /= 2;
tape->buffer_size = *ctl * tape->blk_size;
}
buffer_size = tape->buffer_size;
tape->pages_per_buffer = buffer_size / PAGE_SIZE;
if (buffer_size % PAGE_SIZE) {
tape->pages_per_buffer++;
tape->excess_bh_size = PAGE_SIZE - buffer_size % PAGE_SIZE;
}

/* select the "best" DSC read/write polling freq */
speed = max(*(u16 *)&tape->caps[14], *(u16 *)&tape->caps[8]);

t = (IDETAPE_FIFO_THRESHOLD * tape->buffer_size * HZ) / (speed * 1000);

/*
* Ensure that the number we got makes sense; limit it within
* IDETAPE_DSC_RW_MIN and IDETAPE_DSC_RW_MAX.
*/
tape->best_dsc_rw_freq = clamp_t(unsigned long, t, IDETAPE_DSC_RW_MIN,
IDETAPE_DSC_RW_MAX);
printk(KERN_INFO "ide-tape: %s <-> %s: %dKBps, %d*%dkB buffer, "
"%lums tDSC%s\n",
drive->name, tape->name, *(u16 *)&tape->caps[14],
(*(u16 *)&tape->caps[16] * 512) / tape->buffer_size,
tape->buffer_size / 1024,
tape->best_dsc_rw_freq * 1000 / HZ,
(drive->dev_flags & IDE_DFLAG_USING_DMA) ? ", DMA" : "");

ide_proc_register_driver(drive, tape->driver);
}

static void ide_tape_remove(ide_drive_t *drive)
{
idetape_tape_t *tape = drive->driver_data;

ide_proc_unregister_driver(drive, tape->driver);

ide_unregister_region(tape->disk);

ide_tape_put(tape);
}

static void ide_tape_release(struct kref *kref)
{
struct ide_tape_obj *tape = to_ide_drv(kref, ide_tape_obj);
ide_drive_t *drive = tape->drive;
struct gendisk *g = tape->disk;

BUG_ON(tape->merge_bh_size);

drive->dev_flags &= ~IDE_DFLAG_DSC_OVERLAP;
drive->driver_data = NULL;
device_destroy(idetape_sysfs_class, MKDEV(IDETAPE_MAJOR, tape->minor));
device_destroy(idetape_sysfs_class,
MKDEV(IDETAPE_MAJOR, tape->minor + 128));
idetape_devs[tape->minor] = NULL;
g->private_data = NULL;
put_disk(g);
kfree(tape);
}

#ifdef CONFIG_IDE_PROC_FS
static int proc_idetape_read_name
(char *page, char **start, off_t off, int count, int *eof, void *data)
{
ide_drive_t *drive = (ide_drive_t *) data;
idetape_tape_t *tape = drive->driver_data;
char *out = page;
int len;

len = sprintf(out, "%s\n", tape->name);
PROC_IDE_READ_RETURN(page, start, off, count, eof, len);
}

static ide_proc_entry_t idetape_proc[] = {
{ "capacity", S_IFREG|S_IRUGO, proc_ide_read_capacity, NULL },
{ "name", S_IFREG|S_IRUGO, proc_idetape_read_name, NULL },
{ NULL, 0, NULL, NULL }
};

static ide_proc_entry_t *ide_tape_proc_entries(ide_drive_t *drive)
{
return idetape_proc;
}

static const struct ide_proc_devset *ide_tape_proc_devsets(ide_drive_t *drive)
{
return idetape_settings;
}
#endif

static int ide_tape_probe(ide_drive_t *);

static ide_driver_t idetape_driver = {
.gen_driver = {
.owner = THIS_MODULE,
.name = "ide-tape",
.bus = &ide_bus_type,
},
.probe = ide_tape_probe,
.remove = ide_tape_remove,
.version = IDETAPE_VERSION,
.do_request = idetape_do_request,
.end_request = idetape_end_request,
.error = __ide_error,
#ifdef CONFIG_IDE_PROC_FS
.proc_entries = ide_tape_proc_entries,
.proc_devsets = ide_tape_proc_devsets,
#endif
};

/* Our character device supporting functions, passed to register_chrdev. */
static const struct file_operations idetape_fops = {
.owner = THIS_MODULE,
.read = idetape_chrdev_read,
.write = idetape_chrdev_write,
.ioctl = idetape_chrdev_ioctl,
.open = idetape_chrdev_open,
.release = idetape_chrdev_release,
};

static int idetape_open(struct block_device *bdev, fmode_t mode)
{
struct ide_tape_obj *tape = ide_tape_get(bdev->bd_disk);

if (!tape)
return -ENXIO;

return 0;
}

static int idetape_release(struct gendisk *disk, fmode_t mode)
{
struct ide_tape_obj *tape = ide_drv_g(disk, ide_tape_obj);

ide_tape_put(tape);
return 0;
}

static int idetape_ioctl(struct block_device *bdev, fmode_t mode,
unsigned int cmd, unsigned long arg)
{
struct ide_tape_obj *tape = ide_drv_g(bdev->bd_disk, ide_tape_obj);
ide_drive_t *drive = tape->drive;
int err = generic_ide_ioctl(drive, bdev, cmd, arg);
if (err == -EINVAL)
err = idetape_blkdev_ioctl(drive, cmd, arg);
return err;
}

static struct block_device_operations idetape_block_ops = {
.owner = THIS_MODULE,
.open = idetape_open,
.release = idetape_release,
.locked_ioctl = idetape_ioctl,
};

static int ide_tape_probe(ide_drive_t *drive)
{
idetape_tape_t *tape;
struct gendisk *g;
int minor;

if (!strstr("ide-tape", drive->driver_req))
goto failed;

if (drive->media != ide_tape)
goto failed;

if ((drive->dev_flags & IDE_DFLAG_ID_READ) &&
ide_check_atapi_device(drive, DRV_NAME) == 0) {
printk(KERN_ERR "ide-tape: %s: not supported by this version of"
" the driver\n", drive->name);
goto failed;
}
tape = kzalloc(sizeof(idetape_tape_t), GFP_KERNEL);
if (tape == NULL) {
printk(KERN_ERR "ide-tape: %s: Can't allocate a tape struct\n",
drive->name);
goto failed;
}

g = alloc_disk(1 << PARTN_BITS);
if (!g)
goto out_free_tape;

ide_init_disk(g, drive);

kref_init(&tape->kref);

tape->drive = drive;
tape->driver = &idetape_driver;
tape->disk = g;

g->private_data = &tape->driver;

drive->driver_data = tape;

mutex_lock(&idetape_ref_mutex);
for (minor = 0; idetape_devs[minor]; minor++)
;
idetape_devs[minor] = tape;
mutex_unlock(&idetape_ref_mutex);

idetape_setup(drive, tape, minor);

device_create(idetape_sysfs_class, &drive->gendev,
MKDEV(IDETAPE_MAJOR, minor), NULL, "%s", tape->name);
device_create(idetape_sysfs_class, &drive->gendev,
MKDEV(IDETAPE_MAJOR, minor + 128), NULL,
"n%s", tape->name);

g->fops = &idetape_block_ops;
ide_register_region(g);

return 0;

out_free_tape:
kfree(tape);
failed:
return -ENODEV;
}

static void __exit idetape_exit(void)
{
driver_unregister(&idetape_driver.gen_driver);
class_destroy(idetape_sysfs_class);
unregister_chrdev(IDETAPE_MAJOR, "ht");
}

static int __init idetape_init(void)
{
int error = 1;
idetape_sysfs_class = class_create(THIS_MODULE, "ide_tape");
if (IS_ERR(idetape_sysfs_class)) {
idetape_sysfs_class = NULL;
printk(KERN_ERR "Unable to create sysfs class for ide tapes\n");
error = -EBUSY;
goto out;
}

if (register_chrdev(IDETAPE_MAJOR, "ht", &idetape_fops)) {
printk(KERN_ERR "ide-tape: Failed to register chrdev"
" interface\n");
error = -EBUSY;
goto out_free_class;
}

error = driver_register(&idetape_driver.gen_driver);
if (error)
goto out_free_driver;

return 0;

out_free_driver:
driver_unregister(&idetape_driver.gen_driver);
out_free_class:
class_destroy(idetape_sysfs_class);
out:
return error;
}

MODULE_ALIAS("ide:*m-tape*");
module_init(idetape_init);
module_exit(idetape_exit);
MODULE_ALIAS_CHARDEV_MAJOR(IDETAPE_MAJOR);
MODULE_DESCRIPTION("ATAPI Streaming TAPE Driver");
MODULE_LICENSE("GPL");
\0