From: Cornelia Huck <cohuck@de.ibm.com>
Common i/o layer changes:
- If a device driver tries to start I/O while the common I/O layer wants
to start path verification, don't reject the I/O with -EBUSY (which
might prompt the driver to retry the next tick) but seemingly accept
the I/O and deliver a fake irb with deferred cc 1 after path
verification has finished (prompting the driver to retry the I/O).
This prevents the device driver from doing useless retries while cio
is still busy with path verification.
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
---
25-akpm/drivers/s390/cio/chsc.c | 3 +++
25-akpm/drivers/s390/cio/css.h | 2 ++
25-akpm/drivers/s390/cio/device_fsm.c | 29 +++++++++++++++++++++++++++++
25-akpm/drivers/s390/cio/device_ops.c | 10 ++++++++++
4 files changed, 44 insertions(+)
diff -puN drivers/s390/cio/chsc.c~s390-irb-faking drivers/s390/cio/chsc.c
--- 25/drivers/s390/cio/chsc.c~s390-irb-faking 2005-03-02 17:55:23.000000000 -0800
+++ 25-akpm/drivers/s390/cio/chsc.c 2005-03-02 17:55:23.000000000 -0800
@@ -703,6 +703,9 @@ __check_for_io_and_kill(struct subchanne
{
int cc;
+ if (!device_is_online(sch))
+ /* cio could be doing I/O. */
+ return 0;
cc = stsch(sch->irq, &sch->schib);
if (cc)
return 0;
diff -puN drivers/s390/cio/css.h~s390-irb-faking drivers/s390/cio/css.h
--- 25/drivers/s390/cio/css.h~s390-irb-faking 2005-03-02 17:55:23.000000000 -0800
+++ 25-akpm/drivers/s390/cio/css.h 2005-03-02 17:55:23.000000000 -0800
@@ -84,6 +84,7 @@ struct ccw_device_private {
unsigned int doverify:1; /* delayed path verification */
unsigned int donotify:1; /* call notify function */
unsigned int recog_done:1; /* dev. recog. complete */
+ unsigned int fake_irb:1; /* deliver faked irb */
} __attribute__((packed)) flags;
unsigned long intparm; /* user interruption parameter */
struct qdio_irq *qdio_data;
@@ -136,6 +137,7 @@ void device_set_disconnected(struct subc
void device_trigger_reprobe(struct subchannel *);
/* Helper functions for vary on/off. */
+int device_is_online(struct subchannel *);
void device_set_waiting(struct subchannel *);
/* Machine check helper function. */
diff -puN drivers/s390/cio/device_fsm.c~s390-irb-faking drivers/s390/cio/device_fsm.c
--- 25/drivers/s390/cio/device_fsm.c~s390-irb-faking 2005-03-02 17:55:23.000000000 -0800
+++ 25-akpm/drivers/s390/cio/device_fsm.c 2005-03-02 17:55:23.000000000 -0800
@@ -24,6 +24,17 @@
#include "qdio.h"
int
+device_is_online(struct subchannel *sch)
+{
+ struct ccw_device *cdev;
+
+ if (!sch->dev.driver_data)
+ return 0;
+ cdev = sch->dev.driver_data;
+ return (cdev->private->state == DEV_STATE_ONLINE);
+}
+
+int
device_is_disconnected(struct subchannel *sch)
{
struct ccw_device *cdev;
@@ -44,6 +55,7 @@ device_set_disconnected(struct subchanne
return;
cdev = sch->dev.driver_data;
ccw_device_set_timeout(cdev, 0);
+ cdev->private->flags.fake_irb = 0;
cdev->private->state = DEV_STATE_DISCONNECTED;
}
@@ -474,6 +486,7 @@ ccw_device_nopath_notify(void *data)
} else {
cio_disable_subchannel(sch);
ccw_device_set_timeout(cdev, 0);
+ cdev->private->flags.fake_irb = 0;
cdev->private->state = DEV_STATE_DISCONNECTED;
wake_up(&cdev->private->wait_q);
}
@@ -488,6 +501,21 @@ ccw_device_verify_done(struct ccw_device
cdev->private->options.pgroup = 0;
case 0:
ccw_device_done(cdev, DEV_STATE_ONLINE);
+ /* Deliver fake irb to device driver, if needed. */
+ if (cdev->private->flags.fake_irb) {
+ memset(&cdev->private->irb, 0, sizeof(struct irb));
+ cdev->private->irb.scsw = (struct scsw) {
+ .cc = 1,
+ .fctl = SCSW_FCTL_START_FUNC,
+ .actl = SCSW_ACTL_START_PEND,
+ .stctl = SCSW_STCTL_STATUS_PEND,
+ };
+ cdev->private->flags.fake_irb = 0;
+ if (cdev->handler)
+ cdev->handler(cdev, cdev->private->intparm,
+ &cdev->private->irb);
+ memset(&cdev->private->irb, 0, sizeof(struct irb));
+ }
break;
case -ETIME:
ccw_device_done(cdev, DEV_STATE_BOXED);
@@ -639,6 +667,7 @@ ccw_device_online_notoper(struct ccw_dev
if (sch->driver->notify &&
sch->driver->notify(&sch->dev, sch->lpm ? CIO_GONE : CIO_NO_PATH)) {
ccw_device_set_timeout(cdev, 0);
+ cdev->private->flags.fake_irb = 0;
cdev->private->state = DEV_STATE_DISCONNECTED;
wake_up(&cdev->private->wait_q);
return;
diff -puN drivers/s390/cio/device_ops.c~s390-irb-faking drivers/s390/cio/device_ops.c
--- 25/drivers/s390/cio/device_ops.c~s390-irb-faking 2005-03-02 17:55:23.000000000 -0800
+++ 25-akpm/drivers/s390/cio/device_ops.c 2005-03-02 17:55:23.000000000 -0800
@@ -81,6 +81,16 @@ ccw_device_start_key(struct ccw_device *
return -ENODEV;
if (cdev->private->state == DEV_STATE_NOT_OPER)
return -ENODEV;
+ if (cdev->private->state == DEV_STATE_VERIFY) {
+ /* Remember to fake irb when finished. */
+ if (!cdev->private->flags.fake_irb) {
+ cdev->private->flags.fake_irb = 1;
+ cdev->private->intparm = intparm;
+ return 0;
+ } else
+ /* There's already a fake I/O around. */
+ return -EBUSY;
+ }
if (cdev->private->state != DEV_STATE_ONLINE ||
((sch->schib.scsw.stctl & SCSW_STCTL_PRIM_STATUS) &&
!(sch->schib.scsw.stctl & SCSW_STCTL_SEC_STATUS)) ||
_