From: Cornelia Huck <[email protected]>
[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: Cornelia Huck <[email protected]>
Signed-off-by: Martin Schwidefsky <[email protected]>
---
drivers/s390/cio/cio.c | 1 +
drivers/s390/cio/cio.h | 3 ++-
drivers/s390/cio/css.c | 24 +++++++++++++++++++++---
drivers/s390/cio/css.h | 2 ++
drivers/s390/cio/device.c | 6 +++---
5 files changed, 29 insertions(+), 7 deletions(-)
diff -urpN linux-2.6/drivers/s390/cio/cio.c linux-2.6-patched/drivers/s390/cio/cio.c
--- linux-2.6/drivers/s390/cio/cio.c 2006-07-10 10:33:26.000000000 +0200
+++ linux-2.6-patched/drivers/s390/cio/cio.c 2006-07-10 10:33:41.000000000 +0200
@@ -519,6 +519,7 @@ cio_validate_subchannel (struct subchann
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,
diff -urpN linux-2.6/drivers/s390/cio/cio.h linux-2.6-patched/drivers/s390/cio/cio.h
--- linux-2.6/drivers/s390/cio/cio.h 2006-06-18 03:49:35.000000000 +0200
+++ linux-2.6-patched/drivers/s390/cio/cio.h 2006-07-10 10:33:41.000000000 +0200
@@ -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,
diff -urpN linux-2.6/drivers/s390/cio/css.c linux-2.6-patched/drivers/s390/cio/css.c
--- linux-2.6/drivers/s390/cio/css.c 2006-07-10 10:33:26.000000000 +0200
+++ linux-2.6-patched/drivers/s390/cio/css.c 2006-07-10 10:33:41.000000000 +0200
@@ -108,6 +108,24 @@ css_subchannel_release(struct device *de
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 subchanne
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 subchanne
* 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 subchanne
* 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);
diff -urpN linux-2.6/drivers/s390/cio/css.h linux-2.6-patched/drivers/s390/cio/css.h
--- linux-2.6/drivers/s390/cio/css.h 2006-06-18 03:49:35.000000000 +0200
+++ linux-2.6-patched/drivers/s390/cio/css.h 2006-07-10 10:33:41.000000000 +0200
@@ -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 *);
diff -urpN linux-2.6/drivers/s390/cio/device.c linux-2.6-patched/drivers/s390/cio/device.c
--- linux-2.6/drivers/s390/cio/device.c 2006-07-10 10:33:26.000000000 +0200
+++ linux-2.6-patched/drivers/s390/cio/device.c 2006-07-10 10:33:41.000000000 +0200
@@ -280,7 +280,7 @@ ccw_device_remove_disconnected(struct cc
* '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 *dat
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);
-
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