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Commit d7d12ef2 authored by Peter Oberparleiter's avatar Peter Oberparleiter Committed by Martin Schwidefsky
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[S390] cio: make steal lock procedure more robust 



An Unconditional Reserve + Release operation (steal lock) for a
boxed device may fail when encountering special error cases
(e.g. unit checks or path errors). Fix this by using the more
robust ccw_request infrastructure for performing the steal lock
CCW program.

Signed-off-by: default avatarPeter Oberparleiter <peter.oberparleiter@de.ibm.com>
Signed-off-by: default avatarMartin Schwidefsky <schwidefsky@de.ibm.com>
parent 52ef0608

drivers/s390/cio/device.h

+4 −0
Original line number Diff line number Diff line
@@ -28,6 +28,7 @@ enum dev_state { 
	DEV_STATE_DISCONNECTED_SENSE_ID,

	DEV_STATE_CMFCHANGE,

	DEV_STATE_CMFUPDATE,

	DEV_STATE_STEAL_LOCK,

	/* last element! */

	NR_DEV_STATES

};
@@ -116,6 +117,9 @@ void ccw_device_verify_done(struct ccw_device *, int); 
void ccw_device_disband_start(struct ccw_device *);

void ccw_device_disband_done(struct ccw_device *, int);



void ccw_device_stlck_start(struct ccw_device *, void *, void *, void *);

void ccw_device_stlck_done(struct ccw_device *, void *, int);



int ccw_device_call_handler(struct ccw_device *);



int ccw_device_stlck(struct ccw_device *);

drivers/s390/cio/device_fsm.c

+26 −29
Original line number Diff line number Diff line
@@ -640,6 +640,23 @@ ccw_device_online_verify(struct ccw_device *cdev, enum dev_event dev_event) 
	ccw_device_verify_start(cdev);

}



/*

 * Handle path verification event in boxed state.

 */

static void ccw_device_boxed_verify(struct ccw_device *cdev,

				    enum dev_event dev_event)

{

	struct subchannel *sch = to_subchannel(cdev->dev.parent);



	if (cdev->online) {

		if (cio_enable_subchannel(sch, (u32) (addr_t) sch))

			ccw_device_done(cdev, DEV_STATE_NOT_OPER);

		else

			ccw_device_online_verify(cdev, dev_event);

	} else

		css_schedule_eval(sch->schid);

}



/*

 * Got an interrupt for a normal io (state online).

 */
@@ -816,32 +833,6 @@ ccw_device_delay_verify(struct ccw_device *cdev, enum dev_event dev_event) 
	cdev->private->flags.doverify = 1;

}



static void

ccw_device_stlck_done(struct ccw_device *cdev, enum dev_event dev_event)

{

	struct irb *irb;



	switch (dev_event) {

	case DEV_EVENT_INTERRUPT:

		irb = (struct irb *) __LC_IRB;

		/* Check for unsolicited interrupt. */

		if ((scsw_stctl(&irb->scsw) ==

		     (SCSW_STCTL_STATUS_PEND | SCSW_STCTL_ALERT_STATUS)) &&

		    (!scsw_cc(&irb->scsw)))

			/* FIXME: we should restart stlck here, but this

			 * is extremely unlikely ... */

			goto out_wakeup;



		ccw_device_accumulate_irb(cdev, irb);

		/* We don't care about basic sense etc. */

		break;

	default: /* timeout */

		break;

	}

out_wakeup:

	wake_up(&cdev->private->wait_q);

}



static void

ccw_device_start_id(struct ccw_device *cdev, enum dev_event dev_event)

{
@@ -1010,9 +1001,9 @@ fsm_func_t *dev_jumptable[NR_DEV_STATES][NR_DEV_EVENTS] = { 
	},

	[DEV_STATE_BOXED] = {

		[DEV_EVENT_NOTOPER]	= ccw_device_generic_notoper,

		[DEV_EVENT_INTERRUPT]	= ccw_device_stlck_done,

		[DEV_EVENT_TIMEOUT]	= ccw_device_stlck_done,

		[DEV_EVENT_VERIFY]	= ccw_device_nop,

		[DEV_EVENT_INTERRUPT]	= ccw_device_nop,

		[DEV_EVENT_TIMEOUT]	= ccw_device_nop,

		[DEV_EVENT_VERIFY]	= ccw_device_boxed_verify,

	},

	/* states to wait for i/o completion before doing something */

	[DEV_STATE_TIMEOUT_KILL] = {
@@ -1052,6 +1043,12 @@ fsm_func_t *dev_jumptable[NR_DEV_STATES][NR_DEV_EVENTS] = { 
		[DEV_EVENT_TIMEOUT]	= ccw_device_update_cmfblock,

		[DEV_EVENT_VERIFY]	= ccw_device_update_cmfblock,

	},

	[DEV_STATE_STEAL_LOCK] = {

		[DEV_EVENT_NOTOPER]	= ccw_device_request_event,

		[DEV_EVENT_INTERRUPT]	= ccw_device_request_event,

		[DEV_EVENT_TIMEOUT]	= ccw_device_request_event,

		[DEV_EVENT_VERIFY]	= ccw_device_nop,

	},

};



EXPORT_SYMBOL_GPL(ccw_device_set_timeout);

drivers/s390/cio/device_ops.c

+52 −60
Original line number Diff line number Diff line
@@ -11,6 +11,7 @@ 
#include <linux/list.h>

#include <linux/device.h>

#include <linux/delay.h>

#include <linux/completion.h>



#include <asm/ccwdev.h>

#include <asm/idals.h>
@@ -504,74 +505,65 @@ __u8 ccw_device_get_path_mask(struct ccw_device *cdev) 
	return sch->lpm;

}



struct stlck_data {

	struct completion done;

	int rc;

};



void ccw_device_stlck_done(struct ccw_device *cdev, void *data, int rc)

{

	struct stlck_data *sdata = data;



	sdata->rc = rc;

	complete(&sdata->done);

}



/*

 * Try to break the lock on a boxed device.

 * Perform unconditional reserve + release.

 */

int

ccw_device_stlck(struct ccw_device *cdev)

int ccw_device_stlck(struct ccw_device *cdev)

{

	void *buf, *buf2;

	unsigned long flags;

	struct subchannel *sch;

	int ret;



	if (!cdev)

		return -ENODEV;

	struct subchannel *sch = to_subchannel(cdev->dev.parent);

	struct stlck_data data;

	u8 *buffer;

	int rc;



	if (cdev->drv && !cdev->private->options.force)

	/* Check if steal lock operation is valid for this device. */

	if (cdev->drv) {

		if (!cdev->private->options.force)

			return -EINVAL;



	sch = to_subchannel(cdev->dev.parent);

	

	CIO_TRACE_EVENT(2, "stl lock");

	CIO_TRACE_EVENT(2, dev_name(&cdev->dev));



	buf = kmalloc(32*sizeof(char), GFP_DMA|GFP_KERNEL);

	if (!buf)

		return -ENOMEM;

	buf2 = kmalloc(32*sizeof(char), GFP_DMA|GFP_KERNEL);

	if (!buf2) {

		kfree(buf);

		return -ENOMEM;

	}

	spin_lock_irqsave(sch->lock, flags);

	ret = cio_enable_subchannel(sch, (u32)(addr_t)sch);

	if (ret)

		goto out_unlock;

	/*

	 * Setup ccw. We chain an unconditional reserve and a release so we

	 * only break the lock.

	 */

	cdev->private->iccws[0].cmd_code = CCW_CMD_STLCK;

	cdev->private->iccws[0].cda = (__u32) __pa(buf);

	cdev->private->iccws[0].count = 32;

	cdev->private->iccws[0].flags = CCW_FLAG_CC;

	cdev->private->iccws[1].cmd_code = CCW_CMD_RELEASE;

	cdev->private->iccws[1].cda = (__u32) __pa(buf2);

	cdev->private->iccws[1].count = 32;

	cdev->private->iccws[1].flags = 0;

	ret = cio_start(sch, cdev->private->iccws, 0);

	if (ret) {

		cio_disable_subchannel(sch); //FIXME: return code?

	buffer = kzalloc(64, GFP_DMA | GFP_KERNEL);

	if (!buffer)

		return -ENOMEM;

	init_completion(&data.done);

	data.rc = -EIO;

	spin_lock_irq(sch->lock);

	rc = cio_enable_subchannel(sch, (u32) (addr_t) sch);

	if (rc)

		goto out_unlock;

	/* Perform operation. */

	cdev->private->state = DEV_STATE_STEAL_LOCK,

	ccw_device_stlck_start(cdev, &data, &buffer[0], &buffer[32]);

	spin_unlock_irq(sch->lock);

	/* Wait for operation to finish. */

	if (wait_for_completion_interruptible(&data.done)) {

		/* Got a signal. */

		spin_lock_irq(sch->lock);

		ccw_request_cancel(cdev);

		spin_unlock_irq(sch->lock);

		wait_for_completion(&data.done);

	}

	cdev->private->irb.scsw.cmd.actl |= SCSW_ACTL_START_PEND;

	spin_unlock_irqrestore(sch->lock, flags);

	wait_event(cdev->private->wait_q,

		   cdev->private->irb.scsw.cmd.actl == 0);

	spin_lock_irqsave(sch->lock, flags);

	cio_disable_subchannel(sch); //FIXME: return code?

	if ((cdev->private->irb.scsw.cmd.dstat !=

	     (DEV_STAT_CHN_END|DEV_STAT_DEV_END)) ||

	    (cdev->private->irb.scsw.cmd.cstat != 0))

		ret = -EIO;

	/* Clear irb. */

	memset(&cdev->private->irb, 0, sizeof(struct irb));

	rc = data.rc;

	/* Check results. */

	spin_lock_irq(sch->lock);

	cio_disable_subchannel(sch);

	cdev->private->state = DEV_STATE_BOXED;

out_unlock:

	kfree(buf);

	kfree(buf2);

	spin_unlock_irqrestore(sch->lock, flags);

	return ret;

	spin_unlock_irq(sch->lock);

	kfree(buffer);



	return rc;

}



void *ccw_device_get_chp_desc(struct ccw_device *cdev, int chp_no)

drivers/s390/cio/device_pgid.c

+52 −0
Original line number Diff line number Diff line
@@ -507,3 +507,55 @@ void ccw_device_disband_start(struct ccw_device *cdev) 
	spid_build_cp(cdev, fn);

	ccw_request_start(cdev);

}



static void stlck_build_cp(struct ccw_device *cdev, void *buf1, void *buf2)

{

	struct ccw_request *req = &cdev->private->req;

	struct ccw1 *cp = cdev->private->iccws;



	cp[0].cmd_code = CCW_CMD_STLCK;

	cp[0].cda = (u32) (addr_t) buf1;

	cp[0].count = 32;

	cp[0].flags = CCW_FLAG_CC;

	cp[1].cmd_code = CCW_CMD_RELEASE;

	cp[1].cda = (u32) (addr_t) buf2;

	cp[1].count = 32;

	cp[1].flags = 0;

	req->cp = cp;

}



static void stlck_callback(struct ccw_device *cdev, void *data, int rc)

{

	ccw_device_stlck_done(cdev, data, rc);

}



/**

 * ccw_device_stlck_start - perform unconditional release

 * @cdev: ccw device

 * @data: data pointer to be passed to ccw_device_stlck_done

 * @buf1: data pointer used in channel program

 * @buf2: data pointer used in channel program

 *

 * Execute a channel program on @cdev to release an existing PGID reservation.

 * When finished, call ccw_device_stlck_done with a return code specifying the

 * result.

 */

void ccw_device_stlck_start(struct ccw_device *cdev, void *data, void *buf1,

			    void *buf2)

{

	struct subchannel *sch = to_subchannel(cdev->dev.parent);

	struct ccw_request *req = &cdev->private->req;



	CIO_TRACE_EVENT(4, "stlck");

	CIO_HEX_EVENT(4, &cdev->private->dev_id, sizeof(cdev->private->dev_id));

	/* Request setup. */

	memset(req, 0, sizeof(*req));

	req->timeout	= PGID_TIMEOUT;

	req->maxretries	= PGID_RETRIES;

	req->lpm	= sch->schib.pmcw.pam & sch->opm;

	req->data	= data;

	req->callback	= stlck_callback;

	stlck_build_cp(cdev, buf1, buf2);

	ccw_request_start(cdev);

}