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Commit d7b5a4c9 authored by Cornelia Huck's avatar Cornelia Huck Committed by Martin Schwidefsky
Browse files

[S390] Support for disconnected devices reappearing on another subchannel. 



- create a 'pseudo_subchannel' per channel subsystem (the 'orphanage')
- use the orphanage as a shelter for ccw_devices that can't remain on the same
  subchannel

Signed-off-by: default avatarCornelia Huck <cornelia.huck@de.ibm.com>
Cc: Greg KH <greg@kroah.com>
Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
Signed-off-by: default avatarMartin Schwidefsky <schwidefsky@de.ibm.com>
parent 2ec22984

drivers/s390/cio/cio.c

+5 −1
Original line number Diff line number Diff line
@@ -415,6 +415,8 @@ cio_enable_subchannel (struct subchannel *sch, unsigned int isc) 
	CIO_TRACE_EVENT (2, "ensch");

	CIO_TRACE_EVENT (2, sch->dev.bus_id);



	if (sch_is_pseudo_sch(sch))

		return -EINVAL;

	ccode = stsch (sch->schid, &sch->schib);

	if (ccode)

		return -ENODEV;
@@ -462,6 +464,8 @@ cio_disable_subchannel (struct subchannel *sch) 
	CIO_TRACE_EVENT (2, "dissch");

	CIO_TRACE_EVENT (2, sch->dev.bus_id);



	if (sch_is_pseudo_sch(sch))

		return 0;

	ccode = stsch (sch->schid, &sch->schib);

	if (ccode == 3)		/* Not operational. */

		return -ENODEV;
@@ -496,7 +500,7 @@ cio_disable_subchannel (struct subchannel *sch) 
	return ret;

}



static int cio_create_sch_lock(struct subchannel *sch)

int cio_create_sch_lock(struct subchannel *sch)

{

	sch->lock = kmalloc(sizeof(spinlock_t), GFP_KERNEL);

	if (!sch->lock)

drivers/s390/cio/cio.h

+2 −0
Original line number Diff line number Diff line
@@ -131,6 +131,8 @@ extern int cio_set_options (struct subchannel *, int); 
extern int cio_get_options (struct subchannel *);

extern int cio_modify (struct subchannel *);



int cio_create_sch_lock(struct subchannel *);



/* Use with care. */

#ifdef CONFIG_CCW_CONSOLE

extern struct subchannel *cio_probe_console(void);

drivers/s390/cio/css.c

+33 −4
Original line number Diff line number Diff line
@@ -580,12 +580,24 @@ css_cm_enable_store(struct device *dev, struct device_attribute *attr, 


static DEVICE_ATTR(cm_enable, 0644, css_cm_enable_show, css_cm_enable_store);



static inline void __init

setup_css(int nr)

static inline int __init setup_css(int nr)

{

	u32 tod_high;

	int ret;



	memset(css[nr], 0, sizeof(struct channel_subsystem));

	css[nr]->pseudo_subchannel =

		kzalloc(sizeof(*css[nr]->pseudo_subchannel), GFP_KERNEL);

	if (!css[nr]->pseudo_subchannel)

		return -ENOMEM;

	css[nr]->pseudo_subchannel->dev.parent = &css[nr]->device;

	css[nr]->pseudo_subchannel->dev.release = css_subchannel_release;

	sprintf(css[nr]->pseudo_subchannel->dev.bus_id, "defunct");

	ret = cio_create_sch_lock(css[nr]->pseudo_subchannel);

	if (ret) {

		kfree(css[nr]->pseudo_subchannel);

		return ret;

	}

	mutex_init(&css[nr]->mutex);

	css[nr]->valid = 1;

	css[nr]->cssid = nr;
@@ -593,6 +605,7 @@ setup_css(int nr) 
	css[nr]->device.release = channel_subsystem_release;

	tod_high = (u32) (get_clock() >> 32);

	css_generate_pgid(css[nr], tod_high);

	return 0;

}



/*
@@ -629,10 +642,12 @@ init_channel_subsystem (void) 
			ret = -ENOMEM;

			goto out_unregister;

		}

		setup_css(i);

		ret = device_register(&css[i]->device);

		ret = setup_css(i);

		if (ret)

			goto out_free;

		ret = device_register(&css[i]->device);

		if (ret)

			goto out_free_all;

		if (css_characteristics_avail &&

		    css_chsc_characteristics.secm) {

			ret = device_create_file(&css[i]->device,
@@ -640,6 +655,9 @@ init_channel_subsystem (void) 
			if (ret)

				goto out_device;

		}

		ret = device_register(&css[i]->pseudo_subchannel->dev);

		if (ret)

			goto out_file;

	}

	css_init_done = 1;
@@ -647,13 +665,19 @@ init_channel_subsystem (void) 


	for_each_subchannel(__init_channel_subsystem, NULL);

	return 0;

out_file:

	device_remove_file(&css[i]->device, &dev_attr_cm_enable);

out_device:

	device_unregister(&css[i]->device);

out_free_all:

	kfree(css[i]->pseudo_subchannel->lock);

	kfree(css[i]->pseudo_subchannel);

out_free:

	kfree(css[i]);

out_unregister:

	while (i > 0) {

		i--;

		device_unregister(&css[i]->pseudo_subchannel->dev);

		if (css_characteristics_avail && css_chsc_characteristics.secm)

			device_remove_file(&css[i]->device,

					   &dev_attr_cm_enable);
@@ -665,6 +689,11 @@ init_channel_subsystem (void) 
	return ret;

}



int sch_is_pseudo_sch(struct subchannel *sch)

{

	return sch == to_css(sch->dev.parent)->pseudo_subchannel;

}



/*

 * find a driver for a subchannel. They identify by the subchannel

 * type with the exception that the console subchannel driver has its own

drivers/s390/cio/css.h

+4 −0
Original line number Diff line number Diff line
@@ -160,6 +160,8 @@ struct channel_subsystem { 
	int cm_enabled;

	void *cub_addr1;

	void *cub_addr2;

	/* for orphaned ccw devices */

	struct subchannel *pseudo_subchannel;

};

#define to_css(dev) container_of(dev, struct channel_subsystem, device)
@@ -187,6 +189,8 @@ void css_clear_subchannel_slow_list(void); 
int css_slow_subchannels_exist(void);

extern int need_rescan;



int sch_is_pseudo_sch(struct subchannel *);



extern struct workqueue_struct *slow_path_wq;

extern struct work_struct slow_path_work;

drivers/s390/cio/device.c

+237 −50
Original line number Diff line number Diff line
@@ -23,6 +23,7 @@ 
#include <asm/param.h>		/* HZ */



#include "cio.h"

#include "cio_debug.h"

#include "css.h"

#include "device.h"

#include "ioasm.h"
@@ -294,6 +295,11 @@ online_show (struct device *dev, struct device_attribute *attr, char *buf) 
	return sprintf(buf, cdev->online ? "1\n" : "0\n");

}



int ccw_device_is_orphan(struct ccw_device *cdev)

{

	return sch_is_pseudo_sch(to_subchannel(cdev->dev.parent));

}



static void ccw_device_unregister(struct work_struct *work)

{

	struct ccw_device_private *priv;
@@ -310,10 +316,23 @@ static void 
ccw_device_remove_disconnected(struct ccw_device *cdev)

{

	struct subchannel *sch;

	unsigned long flags;

	/*

	 * Forced offline in disconnected state means

	 * 'throw away device'.

	 */

	if (ccw_device_is_orphan(cdev)) {

		/* Deregister ccw device. */

		spin_lock_irqsave(cdev->ccwlock, flags);

		cdev->private->state = DEV_STATE_NOT_OPER;

		spin_unlock_irqrestore(cdev->ccwlock, flags);

		if (get_device(&cdev->dev)) {

			PREPARE_WORK(&cdev->private->kick_work,

				     ccw_device_unregister);

			queue_work(ccw_device_work, &cdev->private->kick_work);

		}

		return ;

	}

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

	css_sch_device_unregister(sch);

	/* Reset intparm to zeroes. */
@@ -474,6 +493,8 @@ available_show (struct device *dev, struct device_attribute *attr, char *buf) 
	struct ccw_device *cdev = to_ccwdev(dev);

	struct subchannel *sch;



	if (ccw_device_is_orphan(cdev))

		return sprintf(buf, "no device\n");

	switch (cdev->private->state) {

	case DEV_STATE_BOXED:

		return sprintf(buf, "boxed\n");
@@ -574,11 +595,10 @@ match_devno(struct device * dev, void * data) 


	cdev = to_ccwdev(dev);

	if ((cdev->private->state == DEV_STATE_DISCONNECTED) &&

	    !ccw_device_is_orphan(cdev) &&

	    ccw_dev_id_is_equal(&cdev->private->dev_id, &d->dev_id) &&

	    (cdev != d->sibling)) {

		cdev->private->state = DEV_STATE_NOT_OPER;

	    (cdev != d->sibling))

		return 1;

	}

	return 0;

}
@@ -595,6 +615,28 @@ static struct ccw_device * get_disc_ccwdev_by_dev_id(struct ccw_dev_id *dev_id, 
	return dev ? to_ccwdev(dev) : NULL;

}



static int match_orphan(struct device *dev, void *data)

{

	struct ccw_dev_id *dev_id;

	struct ccw_device *cdev;



	dev_id = data;

	cdev = to_ccwdev(dev);

	return ccw_dev_id_is_equal(&cdev->private->dev_id, dev_id);

}



static struct ccw_device *

get_orphaned_ccwdev_by_dev_id(struct channel_subsystem *css,

			      struct ccw_dev_id *dev_id)

{

	struct device *dev;



	dev = device_find_child(&css->pseudo_subchannel->dev, dev_id,

				match_orphan);



	return dev ? to_ccwdev(dev) : NULL;

}



static void

ccw_device_add_changed(struct work_struct *work)

{
@@ -614,64 +656,19 @@ ccw_device_add_changed(struct work_struct *work) 
	}

}



extern int css_get_ssd_info(struct subchannel *sch);



void

ccw_device_do_unreg_rereg(struct work_struct *work)

void ccw_device_do_unreg_rereg(struct work_struct *work)

{

	struct ccw_device_private *priv;

	struct ccw_device *cdev;

	struct subchannel *sch;

	int need_rename;



	priv = container_of(work, struct ccw_device_private, kick_work);

	cdev = priv->cdev;

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

	if (cdev->private->dev_id.devno != sch->schib.pmcw.dev) {

		/*

		 * The device number has changed. This is usually only when

		 * a device has been detached under VM and then re-appeared

		 * on another subchannel because of a different attachment

		 * order than before. Ideally, we should should just switch

		 * subchannels, but unfortunately, this is not possible with

		 * the current implementation.

		 * Instead, we search for the old subchannel for this device

		 * number and deregister so there are no collisions with the

		 * newly registered ccw_device.

		 * FIXME: Find another solution so the block layer doesn't

		 *        get possibly sick...

		 */

		struct ccw_device *other_cdev;

		struct ccw_dev_id dev_id;



		need_rename = 1;

		dev_id.devno = sch->schib.pmcw.dev;

		dev_id.ssid = sch->schid.ssid;

		other_cdev = get_disc_ccwdev_by_dev_id(&dev_id, cdev);

		if (other_cdev) {

			struct subchannel *other_sch;



			other_sch = to_subchannel(other_cdev->dev.parent);

			if (get_device(&other_sch->dev)) {

				stsch(other_sch->schid, &other_sch->schib);

				if (other_sch->schib.pmcw.dnv) {

					other_sch->schib.pmcw.intparm = 0;

					cio_modify(other_sch);

				}

				css_sch_device_unregister(other_sch);

			}

		}

		/* Update ssd info here. */

		css_get_ssd_info(sch);

		cdev->private->dev_id.devno = sch->schib.pmcw.dev;

	} else

		need_rename = 0;

	device_remove_files(&cdev->dev);

	if (test_and_clear_bit(1, &cdev->private->registered))

		device_del(&cdev->dev);

	if (need_rename)

		snprintf (cdev->dev.bus_id, BUS_ID_SIZE, "0.%x.%04x",

			  sch->schid.ssid, sch->schib.pmcw.dev);

	PREPARE_WORK(&cdev->private->kick_work,

		     ccw_device_add_changed);

	queue_work(ccw_device_work, &cdev->private->kick_work);
@@ -736,6 +733,131 @@ static struct ccw_device * io_subchannel_create_ccwdev(struct subchannel *sch) 
	return cdev;

}



static int io_subchannel_recog(struct ccw_device *, struct subchannel *);



static void sch_attach_device(struct subchannel *sch,

			      struct ccw_device *cdev)

{

	spin_lock_irq(sch->lock);

	sch->dev.driver_data = cdev;

	cdev->private->schid = sch->schid;

	cdev->ccwlock = sch->lock;

	device_trigger_reprobe(sch);

	spin_unlock_irq(sch->lock);

}



static void sch_attach_disconnected_device(struct subchannel *sch,

					   struct ccw_device *cdev)

{

	struct subchannel *other_sch;

	int ret;



	other_sch = to_subchannel(get_device(cdev->dev.parent));

	ret = device_move(&cdev->dev, &sch->dev);

	if (ret) {

		CIO_MSG_EVENT(2, "Moving disconnected device 0.%x.%04x failed "

			      "(ret=%d)!\n", cdev->private->dev_id.ssid,

			      cdev->private->dev_id.devno, ret);

		put_device(&other_sch->dev);

		return;

	}

	other_sch->dev.driver_data = NULL;

	/* No need to keep a subchannel without ccw device around. */

	css_sch_device_unregister(other_sch);

	put_device(&other_sch->dev);

	sch_attach_device(sch, cdev);

}



static void sch_attach_orphaned_device(struct subchannel *sch,

				       struct ccw_device *cdev)

{

	int ret;



	/* Try to move the ccw device to its new subchannel. */

	ret = device_move(&cdev->dev, &sch->dev);

	if (ret) {

		CIO_MSG_EVENT(0, "Moving device 0.%x.%04x from orphanage "

			      "failed (ret=%d)!\n",

			      cdev->private->dev_id.ssid,

			      cdev->private->dev_id.devno, ret);

		return;

	}

	sch_attach_device(sch, cdev);

}



static void sch_create_and_recog_new_device(struct subchannel *sch)

{

	struct ccw_device *cdev;



	/* Need to allocate a new ccw device. */

	cdev = io_subchannel_create_ccwdev(sch);

	if (IS_ERR(cdev)) {

		/* OK, we did everything we could... */

		css_sch_device_unregister(sch);

		return;

	}

	spin_lock_irq(sch->lock);

	sch->dev.driver_data = cdev;

	spin_unlock_irq(sch->lock);

	/* Start recognition for the new ccw device. */

	if (io_subchannel_recog(cdev, sch)) {

		spin_lock_irq(sch->lock);

		sch->dev.driver_data = NULL;

		spin_unlock_irq(sch->lock);

		if (cdev->dev.release)

			cdev->dev.release(&cdev->dev);

		css_sch_device_unregister(sch);

	}

}





void ccw_device_move_to_orphanage(struct work_struct *work)

{

	struct ccw_device_private *priv;

	struct ccw_device *cdev;

	struct ccw_device *replacing_cdev;

	struct subchannel *sch;

	int ret;

	struct channel_subsystem *css;

	struct ccw_dev_id dev_id;



	priv = container_of(work, struct ccw_device_private, kick_work);

	cdev = priv->cdev;

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

	css = to_css(sch->dev.parent);

	dev_id.devno = sch->schib.pmcw.dev;

	dev_id.ssid = sch->schid.ssid;



	/*

	 * Move the orphaned ccw device to the orphanage so the replacing

	 * ccw device can take its place on the subchannel.

	 */

	ret = device_move(&cdev->dev, &css->pseudo_subchannel->dev);

	if (ret) {

		CIO_MSG_EVENT(0, "Moving device 0.%x.%04x to orphanage failed "

			      "(ret=%d)!\n", cdev->private->dev_id.ssid,

			      cdev->private->dev_id.devno, ret);

		return;

	}

	cdev->ccwlock = css->pseudo_subchannel->lock;

	/*

	 * Search for the replacing ccw device

	 * - among the disconnected devices

	 * - in the orphanage

	 */

	replacing_cdev = get_disc_ccwdev_by_dev_id(&dev_id, cdev);

	if (replacing_cdev) {

		sch_attach_disconnected_device(sch, replacing_cdev);

		return;

	}

	replacing_cdev = get_orphaned_ccwdev_by_dev_id(css, &dev_id);

	if (replacing_cdev) {

		sch_attach_orphaned_device(sch, replacing_cdev);

		return;

	}

	sch_create_and_recog_new_device(sch);

}



/*

 * Register recognized device.

 */
@@ -890,12 +1012,55 @@ io_subchannel_recog(struct ccw_device *cdev, struct subchannel *sch) 
	return rc;

}



static void ccw_device_move_to_sch(struct work_struct *work)

{

	struct ccw_device_private *priv;

	int rc;

	struct subchannel *sch;

	struct ccw_device *cdev;

	struct subchannel *former_parent;



	priv = container_of(work, struct ccw_device_private, kick_work);

	sch = priv->sch;

	cdev = priv->cdev;

	former_parent = ccw_device_is_orphan(cdev) ?

		NULL : to_subchannel(get_device(cdev->dev.parent));

	mutex_lock(&sch->reg_mutex);

	/* Try to move the ccw device to its new subchannel. */

	rc = device_move(&cdev->dev, &sch->dev);

	mutex_unlock(&sch->reg_mutex);

	if (rc) {

		CIO_MSG_EVENT(2, "Moving device 0.%x.%04x to subchannel "

			      "0.%x.%04x failed (ret=%d)!\n",

			      cdev->private->dev_id.ssid,

			      cdev->private->dev_id.devno, sch->schid.ssid,

			      sch->schid.sch_no, rc);

		css_sch_device_unregister(sch);

		goto out;

	}

	if (former_parent) {

		spin_lock_irq(former_parent->lock);

		former_parent->dev.driver_data = NULL;

		spin_unlock_irq(former_parent->lock);

		css_sch_device_unregister(former_parent);

		/* Reset intparm to zeroes. */

		former_parent->schib.pmcw.intparm = 0;

		cio_modify(former_parent);

	}

	sch_attach_device(sch, cdev);

out:

	if (former_parent)

		put_device(&former_parent->dev);

	put_device(&cdev->dev);

}



static int

io_subchannel_probe (struct subchannel *sch)

{

	struct ccw_device *cdev;

	int rc;

	unsigned long flags;

	struct ccw_dev_id dev_id;



	if (sch->dev.driver_data) {

		/*
@@ -918,6 +1083,28 @@ io_subchannel_probe (struct subchannel *sch) 
			get_device(&cdev->dev);

		return 0;

	}

	/*

	 * First check if a fitting device may be found amongst the

	 * disconnected devices or in the orphanage.

	 */

	dev_id.devno = sch->schib.pmcw.dev;

	dev_id.ssid = sch->schid.ssid;

	cdev = get_disc_ccwdev_by_dev_id(&dev_id, NULL);

	if (!cdev)

		cdev = get_orphaned_ccwdev_by_dev_id(to_css(sch->dev.parent),

						     &dev_id);

	if (cdev) {

		/*

		 * Schedule moving the device until when we have a registered

		 * subchannel to move to and succeed the probe. We can

		 * unregister later again, when the probe is through.

		 */

		cdev->private->sch = sch;

		PREPARE_WORK(&cdev->private->kick_work,

			     ccw_device_move_to_sch);

		queue_work(slow_path_wq, &cdev->private->kick_work);

		return 0;

	}

	cdev = io_subchannel_create_ccwdev(sch);

	if (IS_ERR(cdev))

		return PTR_ERR(cdev);