static int blk_protect_register(request_queue_t *q);

static void blk_protect_unregister(request_queue_t *q);

void blk_queue_issue_protect_fn(request_queue_t *q, issue_protect_fn *ipf)

{

       q->issue_protect_fn = ipf;

}

EXPORT_SYMBOL(blk_queue_issue_protect_fn);

void blk_queue_issue_unprotect_fn(request_queue_t *q, issue_unprotect_fn *iuf)

{

       q->issue_unprotect_fn = iuf;

}

EXPORT_SYMBOL(blk_queue_issue_unprotect_fn);

	blk_protect_register(q);

		blk_protect_unregister(q);

/*

 * Restore the unplugging timer that we re-used

 * to implement the queue freeze timeout...

 */

static void blk_unfreeze_work(void *data)

{

       request_queue_t *q = (request_queue_t *) data;

       INIT_WORK(&q->unplug_work, blk_unplug_work, q);

       q->unplug_timer.function = blk_unplug_timeout;

       q->issue_unprotect_fn(q);

}

/*

 * Called when the queue freeze timeout expires...

 */

static void blk_unfreeze_timeout(unsigned long data)

{

       request_queue_t *q = (request_queue_t *) data;

       kblockd_schedule_work(&q->unplug_work);

}

/*

 * The lower level driver parks and freezes the queue, and this block layer

 *  function sets up the freeze timeout timer on return. If the queue is

 *  already frozen then this is called to extend the timer...

 */

void blk_freeze_queue(request_queue_t *q, int seconds)

{

       /* set/reset the timer */

       mod_timer(&q->unplug_timer, msecs_to_jiffies(seconds*1000) + jiffies);

       /* we do this every iteration - is this sane? */

       INIT_WORK(&q->unplug_work, blk_unfreeze_work, q);

       q->unplug_timer.function = blk_unfreeze_timeout;

}

/*

 * When reading the 'protect' attribute, we return boolean frozen or active

 * todo:

 * - maybe we should return seconds remaining instead?

 */

static ssize_t queue_protect_show(struct request_queue *q, char *page)

{

       return queue_var_show(blk_queue_stopped(q), (page));

}

/*

 * When writing the 'protect' attribute, input is the number of seconds

 * to freeze the queue for. We call a lower level helper function to

 * park the heads and freeze/block the queue, then we make a block layer

 * call to setup the thaw timeout. If input is 0, then we thaw the queue.

 */

static ssize_t queue_protect_store(struct request_queue *q, const char *page, size_t count)

{

       unsigned long freeze = 0;

       queue_var_store(&freeze, page, count);

       if(freeze>0) {

/* Park and freeze */

	       if (!blk_queue_stopped(q))

		       q->issue_protect_fn(q);

/* set / reset the thaw timer */

	       blk_freeze_queue(q, freeze);

       }

       else

	       blk_unfreeze_timeout((unsigned long) q);

       return count;

}

static struct queue_sysfs_entry queue_protect_entry = {

       .attr = {.name = "protect", .mode = S_IRUGO | S_IWUSR },

       .show = queue_protect_show,

       .store = queue_protect_store,

};

static int blk_protect_register(request_queue_t *q)

{

	int error = 0;

/* check that the lower level driver has a protect handler */

	if (!q->issue_protect_fn)

		return 1;

/* create the attribute */

	error = sysfs_create_file(&q->kobj, &queue_protect_entry.attr);

	if(error){

		printk(KERN_ERR

		       "blk_protect_register(): failed to create protect queue attribute!\n");

		return error;

	}

	kobject_get(&q->kobj);

	return 0;

}

static void blk_protect_unregister(request_queue_t *q)

{

/* check that the lower level driver has a protect handler */

	if (!q->issue_protect_fn)

		return;

/* remove the attribute */

	sysfs_remove_file(&q->kobj,&queue_protect_entry.attr);

	kobject_put(&q->kobj);

}

int idedisk_protect_method = 0;

module_param_named(protect_method, idedisk_protect_method, int, 0444);

MODULE_PARM_DESC(protect_method, "hdaps disk protection method (0=autodetect, 1=unload, 2=standby)");

 * todo:

 *  - we freeze the queue regardless of success and rely on the 

 *    ide_protect_queue function to thaw immediately if the command

 *    failed (to be consistent with the libata handler)... should 

 *    we also inspect here?

 */

void ide_end_protect_rq(struct request *rq, int error)

{

	struct completion *waiting = rq->waiting;

	/* spin lock already accquired */

	if (!blk_queue_stopped(rq->q))

		blk_stop_queue(rq->q);

	complete(waiting);

}

int ide_unprotect_queue(request_queue_t *q)

{

	struct request	rq;

	unsigned long flags;

	int		pending = 0, rc = 0;

	ide_drive_t 	*drive = q->queuedata;

	u8 		args[7], *argbuf = args;

	if (!blk_queue_stopped(q))

		return -EIO;

	/* Are there any pending jobs on the queue? */

	pending = ((q->rq.count[READ] > 0) || (q->rq.count[WRITE] > 0)) ? 1 : 0;

	spin_lock_irqsave(q->queue_lock, flags);

	blk_start_queue(q);

	spin_unlock_irqrestore(q->queue_lock, flags);

	/* The unload feature of the IDLE_IMMEDIATE command

	   temporarily disables HD power management from spinning down

	   the disk. Any other command will reenable HD pm, so, if

	   there are no pending jobs on the queue, another

	   CHECK_POWER_MODE1 command without the unload feature should do

	   just fine. */

	if (!pending) {

		printk(KERN_DEBUG "ide_unprotect_queue(): No pending I/O, re-enabling power management..\n");

		memset(args, 0, sizeof(args));

		argbuf[0] = 0xe5; /* CHECK_POWER_MODE1 */

		ide_init_drive_cmd(&rq);

		rq.flags = REQ_DRIVE_TASK;

		rq.buffer = argbuf;

		rc = ide_do_drive_cmd(drive, &rq, ide_head_wait);

	}

	return rc;

}

int ide_protect_queue(request_queue_t *q, int unload)

{

	ide_drive_t 	*drive = q->queuedata;

	struct request	rq;

	u8 		args[7], *argbuf = args;

	int		ret = 0;

	DECLARE_COMPLETION(wait);

	memset(&rq, 0, sizeof(rq));

	memset(args, 0, sizeof(args));

	if (blk_queue_stopped(q))

		return -EIO;

	if (unload) {

		argbuf[0] = 0xe1;

		argbuf[1] = 0x44;

		argbuf[3] = 0x4c;

		argbuf[4] = 0x4e;

		argbuf[5] = 0x55;

	} else

		argbuf[0] = 0xe0;

	/* Issue the park command & freeze */

	ide_init_drive_cmd(&rq);

	rq.flags = REQ_DRIVE_TASK;

	rq.buffer = argbuf;

	rq.waiting = &wait;

	rq.end_io = ide_end_protect_rq;

	ret = ide_do_drive_cmd(drive, &rq, ide_next);

	wait_for_completion(&wait);

	rq.waiting = NULL;

	if (ret)

	{

		printk(KERN_DEBUG "ide_protect_queue(): Warning: head NOT parked!..\n");

		ide_unprotect_queue(q);

		return ret;

	}

	if (unload) {

		if (args[3] == 0xc4)

			printk(KERN_DEBUG "ide_protect_queue(): head parked..\n");

		else {

			/* error parking the head */

			printk(KERN_DEBUG "ide_protect_queue(): head NOT parked!..\n");

			ret = -EIO;

			ide_unprotect_queue(q);

		}

	} else

		printk(KERN_DEBUG "ide_protect_queue(): head park not requested, used standby!..\n");

	return ret;

}	

int idedisk_issue_protect_fn(request_queue_t *q)

{

	ide_drive_t		*drive = q->queuedata;

	int unload;

	/*

	 * Check capability of the device -

	 *  - if "idle immediate with unload" is supported we use that, else

	 *    we use "standby immediate" and live with spinning down the drive..

	 *    (Word 84, bit 13 of IDENTIFY DEVICE data)

	 */

	if (idedisk_protect_method == 1) {

		unload = 1;	

		printk(KERN_DEBUG "idedisk_issue_protect_fn(): unload method requested, overriding drive capability check..\n");

	}

	else if (idedisk_protect_method == 2) {

		unload = 0;	

		printk(KERN_DEBUG "idedisk_issue_protect_fn(): standby method requested, overriding drive capability check..\n");

	}

	else if (drive->id->cfsse & (1 << 13)) {

		unload = 1;

		printk(KERN_DEBUG "idedisk_issue_protect_fn(): unload support reported by drive..\n");

	}

	else {

		unload = 0;

		printk(KERN_DEBUG "idedisk_issue_protect_fn(): unload support NOT reported by drive!..\n");

	}

	return ide_protect_queue(q, unload);

}

int idedisk_issue_unprotect_fn(request_queue_t *q)

{

	return ide_unprotect_queue(q);

}

/*

	blk_queue_issue_protect_fn(drive->queue, idedisk_issue_protect_fn);	

	blk_queue_issue_unprotect_fn(drive->queue, idedisk_issue_unprotect_fn);	

		 * Don't accept a request when the queue is stopped (unless we

		 * are resuming from suspend). Prevents existing queue entries 

		 * being processed after queue is stopped by the hard disk 

		 * protection mechanism...

		 */

		if (test_bit(QUEUE_FLAG_STOPPED, &drive->queue->queue_flags) && !blk_pm_resume_request(rq)) {

			hwgroup->busy = 0;

			break;

		}

		/*

	if (action == ide_next)

		where = ELEVATOR_INSERT_FRONT;

int libata_protect_method = 0;

module_param_named(protect_method, libata_protect_method, int, 0444);

MODULE_PARM_DESC(protect_method, "hdaps disk protection method (0=autodetect, 1=unload, 2=standby)");

extern int libata_protect_method;

extern int scsi_protect_queue(request_queue_t *q, int unload);

extern int scsi_unprotect_queue(request_queue_t *q);

static int ata_scsi_issue_protect_fn(request_queue_t *q)

{

	struct scsi_device *sdev = q->queuedata;

	struct ata_port *ap = (struct ata_port *) &sdev->host->hostdata[0];

	struct ata_device *dev = &ap->device[sdev->id];

	int unload;

	if (libata_protect_method == 1) {

		unload = 1;	

		printk(KERN_DEBUG "ata_scsi_issue_protect_fn(): unload method requested, overriding drive capability check..\n");

	}

	else if (libata_protect_method == 2) {

		unload = 0;	

		printk(KERN_DEBUG "ata_scsi_issue_protect_fn(): standby method requested, overriding drive capability check..\n");

	}

	else if (ata_id_has_unload(dev->id)) {

		unload = 1;

		printk(KERN_DEBUG "ata_scsi_issue_protect_fn(): unload support reported by drive..\n");

	}

	else {

		unload = 0;

		printk(KERN_DEBUG "ata_scsi_issue_protect_fn(): unload support NOT reported by drive!..\n");

	}

	/* call scsi_protect_queue, requesting either unload or standby */

	return scsi_protect_queue(q, unload);

}

static int ata_scsi_issue_unprotect_fn(request_queue_t *q)

{

	return scsi_unprotect_queue(q);

}

	blk_queue_issue_protect_fn(sdev->request_queue, ata_scsi_issue_protect_fn);	

	blk_queue_issue_unprotect_fn(sdev->request_queue, ata_scsi_issue_unprotect_fn);	

/*

 * As per scsi_wait_req_end_io(), which was removed in 2.6.15

 */

static void scsi_protect_wait_req_end_io(struct request *req, int error)

{

	BUG_ON(!req->waiting);

	complete(req->waiting);

}

/*

 * As per scsi_wait_done(), except calls scsi_device_block

 * to block the queue at command completion. Only called by

 * scsi_protect_wait().

 * todo:

 *  - we block the queue regardless of success and rely on the

 *    scsi_protect_queue function to unblock if the command

 *    failed... should we also inspect here?

 */

static void scsi_protect_wait_done(struct scsi_cmnd *cmd)

{

	struct request *req = cmd->request;

	struct request_queue *q = cmd->device->request_queue;

	struct scsi_device *sdev = cmd->device;

	unsigned long flags;

	req->rq_status = RQ_SCSI_DONE;	/* Busy, but indicate request done */

	spin_lock_irqsave(q->queue_lock, flags);

	if (blk_rq_tagged(req))

		blk_queue_end_tag(q, req);

	spin_unlock_irqrestore(q->queue_lock, flags);

	scsi_internal_device_block(sdev);

	if (req->waiting)

		complete(req->waiting);

}

/*

 * As per scsi_wait_req(), except sets the completion function

 * as scsi_protect_wait_done().

 */

void scsi_protect_wait_req(struct scsi_request *sreq, const void *cmnd, void *buffer,

			   unsigned bufflen, int timeout, int retries)

{

	DECLARE_COMPLETION(wait);

	sreq->sr_request->waiting = &wait;

	sreq->sr_request->rq_status = RQ_SCSI_BUSY;

	sreq->sr_request->end_io = scsi_protect_wait_req_end_io;

	scsi_do_req(sreq, cmnd, buffer, bufflen, scsi_protect_wait_done,

		    timeout, retries);

	wait_for_completion(&wait);

	sreq->sr_request->waiting = NULL;

	if (sreq->sr_request->rq_status != RQ_SCSI_DONE)

		sreq->sr_result |= (DRIVER_ERROR << 24);

	__scsi_release_request(sreq);

}

/*

 * scsi_unprotect_queue()

 *  - release the queue that was previously blocked

 */

int scsi_unprotect_queue(request_queue_t *q){

	struct scsi_device *sdev = q->queuedata;

	int rc = 0, pending = 0;

	u8 scsi_cmd[MAX_COMMAND_SIZE];

	struct scsi_sense_hdr sshdr;

	if (sdev->sdev_state != SDEV_BLOCK)

		return -ENXIO;

	/* Are there any pending jobs on the queue? */

			pending = ((q->rq.count[READ] > 0) || (q->rq.count[WRITE] > 0)) ? 1 : 0;

				rc = scsi_internal_device_unblock(sdev);

				if (rc)

					return rc;

				if (!pending) {

printk(KERN_DEBUG "scsi_unprotect_queue(): No pending I/O, re-enabling power management..\n");

memset(scsi_cmd, 0, sizeof(scsi_cmd));

scsi_cmd[0]  = ATA_16;

scsi_cmd[1]  = (3 << 1); /* Non-data */

/* scsi_cmd[2] is already 0 -- no off.line, cc, or data xfer */

scsi_cmd[14] = 0xe5; /* CHECK_POWER_MODE1 */

/* Good values for timeout and retries?  Values below

   from scsi_ioctl_send_command() for default case... */

if (scsi_execute_req(sdev, scsi_cmd, DMA_NONE, NULL, 0, &sshdr,

		     (10*HZ), 5))

	rc = -EIO;

				}

				return rc;

}

EXPORT_SYMBOL_GPL(scsi_unprotect_queue);

/*

 * scsi_protect_queue()

 *  - build and issue the park/standby command..

 *  - queue is blocked during command completion handler

 */

int scsi_protect_queue(request_queue_t *q, int unload)

{

	struct scsi_device *sdev = q->queuedata;

	int rc = 0;

	u8 scsi_cmd[MAX_COMMAND_SIZE];

	u8 args[7];

	struct scsi_request *sreq;

	unsigned char *sb, *desc;

	if (sdev->sdev_state != SDEV_RUNNING)

		return -ENXIO;

	memset(args, 0, sizeof(args));

	if (unload) {

		args[0] = 0xe1;

		args[1] = 0x44;

		args[3] = 0x4c;

		args[4] = 0x4e;

		args[5] = 0x55;

	} else

		args[0] = 0xe0;

	memset(scsi_cmd, 0, sizeof(scsi_cmd));

	scsi_cmd[0]  = ATA_16;

	scsi_cmd[1]  = (3 << 1); /* Non-data */

	scsi_cmd[2]  = 0x20;     /* no off.line, or data xfer, request cc */

	scsi_cmd[4]  = args[1];

	scsi_cmd[6]  = args[2];

	scsi_cmd[8]  = args[3];

	scsi_cmd[10] = args[4];

	scsi_cmd[12] = args[5];

	scsi_cmd[14] = args[0];

	sreq = scsi_allocate_request(sdev, GFP_KERNEL);

	if (!sreq) {

		rc = -EINTR;

		goto error;

	}

	sreq->sr_data_direction = DMA_NONE;

	scsi_protect_wait_req(sreq, scsi_cmd, NULL, 0, (10*HZ), 5);

	if (!sreq->sr_result == ((DRIVER_SENSE << 24) + SAM_STAT_CHECK_CONDITION)) {

		printk(KERN_DEBUG "scsi_protect_queue(): head NOT parked!..\n");

		scsi_unprotect_queue(q);		/* just in case we still managed to block */

		rc = -EIO;

		goto error;

	}

	sb = sreq->sr_sense_buffer;

	desc = sb + 8;

/* Retrieve data from check condition */

	args[1] = desc[3];

	args[2] = desc[5];

	args[3] = desc[7];

	args[4] = desc[9];

	args[5] = desc[11];

	args[0] = desc[13];

	if (unload) {

		if (args[3] == 0xc4)

			printk(KERN_DEBUG "scsi_protect_queue(): head parked..\n");

		else {

/* error parking the head */

			printk(KERN_DEBUG "scsi_protect_queue(): head NOT parked!..\n");

			rc = -EIO;

			scsi_unprotect_queue(q);

		}

	} else

		printk(KERN_DEBUG "scsi_protect_queue(): head park not requested, used standby!..\n");

error:

	scsi_release_request(sreq);

	return rc;

}

EXPORT_SYMBOL_GPL(scsi_protect_queue);

#define ata_id_has_unload(id)   ((id)[84] & (1 << 13))

typedef int (issue_protect_fn) (request_queue_t *);

typedef int (issue_unprotect_fn) (request_queue_t *);

	issue_protect_fn	*issue_protect_fn;

	issue_unprotect_fn	*issue_unprotect_fn;

extern void blk_queue_issue_protect_fn(request_queue_t *, issue_protect_fn *);

extern void blk_queue_issue_unprotect_fn(request_queue_t *, issue_unprotect_fn *);

	ide_next,	/* insert rq immediately after current request */