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Commit 6ab4879a authored by Cornelia Huck's avatar Cornelia Huck Committed by Martin Schwidefsky
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[S390] subchannel register/unregister mutex. 



Add a reg_mutex to prevent unregistering a subchannel before it has been
registered. Since 2.6.17, we've seen oopses in kslowcrw when a device is
found to be not operational during sense id when doing initial device
recognition; it is not clear yet why that particular problem was not (yet)
observed with earlier kernels...

Signed-off-by: default avatarCornelia Huck <cornelia.huck@de.ibm.com>
Signed-off-by: default avatarMartin Schwidefsky <schwidefsky@de.ibm.com>
parent 63f4f9e1

drivers/s390/cio/cio.c

+1 −0
Original line number Diff line number Diff line
@@ -519,6 +519,7 @@ cio_validate_subchannel (struct subchannel *sch, struct subchannel_id schid) 
	memset(sch, 0, sizeof(struct subchannel));



	spin_lock_init(&sch->lock);

	mutex_init(&sch->reg_mutex);



	/* Set a name for the subchannel */

	snprintf (sch->dev.bus_id, BUS_ID_SIZE, "0.%x.%04x", schid.ssid,

drivers/s390/cio/cio.h

+2 −1
Original line number Diff line number Diff line
@@ -2,6 +2,7 @@ 
#define S390_CIO_H



#include "schid.h"

#include <linux/mutex.h>



/*

 * where we put the ssd info
@@ -87,7 +88,7 @@ struct orb { 
struct subchannel {

	struct subchannel_id schid;

	spinlock_t lock;	/* subchannel lock */



	struct mutex reg_mutex;

	enum {

		SUBCHANNEL_TYPE_IO = 0,

		SUBCHANNEL_TYPE_CHSC = 1,

drivers/s390/cio/css.c

+21 −3
Original line number Diff line number Diff line
@@ -108,6 +108,24 @@ css_subchannel_release(struct device *dev) 


extern int css_get_ssd_info(struct subchannel *sch);





int css_sch_device_register(struct subchannel *sch)

{

	int ret;



	mutex_lock(&sch->reg_mutex);

	ret = device_register(&sch->dev);

	mutex_unlock(&sch->reg_mutex);

	return ret;

}



void css_sch_device_unregister(struct subchannel *sch)

{

	mutex_lock(&sch->reg_mutex);

	device_unregister(&sch->dev);

	mutex_unlock(&sch->reg_mutex);

}



static int

css_register_subchannel(struct subchannel *sch)

{
@@ -119,7 +137,7 @@ css_register_subchannel(struct subchannel *sch) 
	sch->dev.release = &css_subchannel_release;

	

	/* make it known to the system */

	ret = device_register(&sch->dev);

	ret = css_sch_device_register(sch);

	if (ret)

		printk (KERN_WARNING "%s: could not register %s\n",

			__func__, sch->dev.bus_id);
@@ -250,7 +268,7 @@ css_evaluate_subchannel(struct subchannel_id schid, int slow) 
		 * The device will be killed automatically.

		 */

		cio_disable_subchannel(sch);

		device_unregister(&sch->dev);

		css_sch_device_unregister(sch);

		/* Reset intparm to zeroes. */

		sch->schib.pmcw.intparm = 0;

		cio_modify(sch);
@@ -264,7 +282,7 @@ css_evaluate_subchannel(struct subchannel_id schid, int slow) 
		 * away in any case.

		 */

		if (!disc) {

			device_unregister(&sch->dev);

			css_sch_device_unregister(sch);

			/* Reset intparm to zeroes. */

			sch->schib.pmcw.intparm = 0;

			cio_modify(sch);

drivers/s390/cio/css.h

+2 −0
Original line number Diff line number Diff line
@@ -136,6 +136,8 @@ extern struct bus_type css_bus_type; 
extern struct css_driver io_subchannel_driver;



extern int css_probe_device(struct subchannel_id);

extern int css_sch_device_register(struct subchannel *);

extern void css_sch_device_unregister(struct subchannel *);

extern struct subchannel * get_subchannel_by_schid(struct subchannel_id);

extern int css_init_done;

extern int for_each_subchannel(int(*fn)(struct subchannel_id, void *), void *);

drivers/s390/cio/device.c

+3 −3
Original line number Diff line number Diff line
@@ -280,7 +280,7 @@ ccw_device_remove_disconnected(struct ccw_device *cdev) 
	 * 'throw away device'.

	 */

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

	device_unregister(&sch->dev);

	css_sch_device_unregister(sch);

	/* Reset intparm to zeroes. */

	sch->schib.pmcw.intparm = 0;

	cio_modify(sch);
@@ -625,7 +625,7 @@ ccw_device_do_unreg_rereg(void *data) 
					other_sch->schib.pmcw.intparm = 0;

					cio_modify(other_sch);

				}

				device_unregister(&other_sch->dev);

				css_sch_device_unregister(other_sch);

			}

		}

		/* Update ssd info here. */
@@ -709,7 +709,7 @@ ccw_device_call_sch_unregister(void *data) 
	struct subchannel *sch;



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

	device_unregister(&sch->dev);

	css_sch_device_unregister(sch);

	/* Reset intparm to zeroes. */

	sch->schib.pmcw.intparm = 0;

	cio_modify(sch);