From 6ab4879a0d074c938fd17dba141dce042fc17bee Mon Sep 17 00:00:00 2001 From: Cornelia Huck Date: Wed, 12 Jul 2006 16:39:50 +0200 Subject: [PATCH] [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 Signed-off-by: Martin Schwidefsky --- 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 --git a/drivers/s390/cio/cio.c b/drivers/s390/cio/cio.c index 6fec90eab00e..f27b2b866f5a 100644 --- a/drivers/s390/cio/cio.c +++ b/drivers/s390/cio/cio.c @@ -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, diff --git a/drivers/s390/cio/cio.h b/drivers/s390/cio/cio.h index 0ca987344e07..4541c1af4b66 100644 --- a/drivers/s390/cio/cio.h +++ b/drivers/s390/cio/cio.h @@ -2,6 +2,7 @@ #define S390_CIO_H #include "schid.h" +#include /* * 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 --git a/drivers/s390/cio/css.c b/drivers/s390/cio/css.c index 1d3be80797f8..a09deea5d687 100644 --- a/drivers/s390/cio/css.c +++ b/drivers/s390/cio/css.c @@ -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); diff --git a/drivers/s390/cio/css.h b/drivers/s390/cio/css.h index e210f89a2449..15f7f7cb0ec2 100644 --- a/drivers/s390/cio/css.h +++ b/drivers/s390/cio/css.h @@ -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 --git a/drivers/s390/cio/device.c b/drivers/s390/cio/device.c index 67f0de6aed33..9db09870b2ae 100644 --- a/drivers/s390/cio/device.c +++ b/drivers/s390/cio/device.c @@ -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); -- 2.20.1