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Subject[patch 19/32] [PATCH] ccw_device_notify: improve return codes
From: Sebastian Ott <sebott@linux.vnet.ibm.com>

Callers of ccw_device_notify could not distinguish between a driver
who has no notifier registered and a driver who doesn't want to keep
a device after a certain event. Change this by adding proper return
codes.

Signed-off-by: Sebastian Ott <sebott@linux.vnet.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
---

drivers/s390/cio/device.c | 10 +++++-----
drivers/s390/cio/device.h | 2 +-
drivers/s390/cio/device_fsm.c | 39 +++++++++++++++++++++++++++++++--------
3 files changed, 37 insertions(+), 14 deletions(-)

Index: quilt-2.6/drivers/s390/cio/device.c
===================================================================
--- quilt-2.6.orig/drivers/s390/cio/device.c 2010-02-24 09:44:23.000000000 +0100
+++ quilt-2.6/drivers/s390/cio/device.c 2010-02-24 09:44:26.000000000 +0100
@@ -1338,7 +1338,7 @@
/* Not operational. */
if (!cdev)
return IO_SCH_UNREG;
- if (!ccw_device_notify(cdev, CIO_GONE))
+ if (ccw_device_notify(cdev, CIO_GONE) != NOTIFY_OK)
return IO_SCH_UNREG;
return IO_SCH_ORPH_UNREG;
}
@@ -1346,12 +1346,12 @@
if (!cdev)
return IO_SCH_ATTACH;
if (sch->schib.pmcw.dev != cdev->private->dev_id.devno) {
- if (!ccw_device_notify(cdev, CIO_GONE))
+ if (ccw_device_notify(cdev, CIO_GONE) != NOTIFY_OK)
return IO_SCH_UNREG_ATTACH;
return IO_SCH_ORPH_ATTACH;
}
if ((sch->schib.pmcw.pam & sch->opm) == 0) {
- if (!ccw_device_notify(cdev, CIO_NO_PATH))
+ if (ccw_device_notify(cdev, CIO_NO_PATH) != NOTIFY_OK)
return IO_SCH_UNREG;
return IO_SCH_DISC;
}
@@ -1788,7 +1788,7 @@
static int resume_handle_boxed(struct ccw_device *cdev)
{
cdev->private->state = DEV_STATE_BOXED;
- if (ccw_device_notify(cdev, CIO_BOXED))
+ if (ccw_device_notify(cdev, CIO_BOXED) == NOTIFY_OK)
return 0;
ccw_device_sched_todo(cdev, CDEV_TODO_UNREG);
return -ENODEV;
@@ -1797,7 +1797,7 @@
static int resume_handle_disc(struct ccw_device *cdev)
{
cdev->private->state = DEV_STATE_DISCONNECTED;
- if (ccw_device_notify(cdev, CIO_GONE))
+ if (ccw_device_notify(cdev, CIO_GONE) == NOTIFY_OK)
return 0;
ccw_device_sched_todo(cdev, CDEV_TODO_UNREG);
return -ENODEV;
Index: quilt-2.6/drivers/s390/cio/device_fsm.c
===================================================================
--- quilt-2.6.orig/drivers/s390/cio/device_fsm.c 2010-02-24 09:28:13.000000000 +0100
+++ quilt-2.6/drivers/s390/cio/device_fsm.c 2010-02-24 09:44:26.000000000 +0100
@@ -313,21 +313,43 @@
}
}

+/**
+ * ccw_device_notify() - inform the device's driver about an event
+ * @cdev: device for which an event occured
+ * @event: event that occurred
+ *
+ * Returns:
+ * -%EINVAL if the device is offline or has no driver.
+ * -%EOPNOTSUPP if the device's driver has no notifier registered.
+ * %NOTIFY_OK if the driver wants to keep the device.
+ * %NOTIFY_BAD if the driver doesn't want to keep the device.
+ */
int ccw_device_notify(struct ccw_device *cdev, int event)
{
+ int ret = -EINVAL;
+
if (!cdev->drv)
- return 0;
+ goto out;
if (!cdev->online)
- return 0;
+ goto out;
CIO_MSG_EVENT(2, "notify called for 0.%x.%04x, event=%d\n",
cdev->private->dev_id.ssid, cdev->private->dev_id.devno,
event);
- return cdev->drv->notify ? cdev->drv->notify(cdev, event) : 0;
+ if (!cdev->drv->notify) {
+ ret = -EOPNOTSUPP;
+ goto out;
+ }
+ if (cdev->drv->notify(cdev, event))
+ ret = NOTIFY_OK;
+ else
+ ret = NOTIFY_BAD;
+out:
+ return ret;
}

static void ccw_device_oper_notify(struct ccw_device *cdev)
{
- if (ccw_device_notify(cdev, CIO_OPER)) {
+ if (ccw_device_notify(cdev, CIO_OPER) == NOTIFY_OK) {
/* Reenable channel measurements, if needed. */
ccw_device_sched_todo(cdev, CDEV_TODO_ENABLE_CMF);
return;
@@ -361,14 +383,15 @@
case DEV_STATE_BOXED:
CIO_MSG_EVENT(0, "Boxed device %04x on subchannel %04x\n",
cdev->private->dev_id.devno, sch->schid.sch_no);
- if (cdev->online && !ccw_device_notify(cdev, CIO_BOXED))
+ if (cdev->online &&
+ ccw_device_notify(cdev, CIO_BOXED) != NOTIFY_OK)
ccw_device_sched_todo(cdev, CDEV_TODO_UNREG);
cdev->private->flags.donotify = 0;
break;
case DEV_STATE_NOT_OPER:
CIO_MSG_EVENT(0, "Device %04x gone on subchannel %04x\n",
cdev->private->dev_id.devno, sch->schid.sch_no);
- if (!ccw_device_notify(cdev, CIO_GONE))
+ if (ccw_device_notify(cdev, CIO_GONE) != NOTIFY_OK)
ccw_device_sched_todo(cdev, CDEV_TODO_UNREG);
else
ccw_device_set_disconnected(cdev);
@@ -378,7 +401,7 @@
CIO_MSG_EVENT(0, "Disconnected device %04x on subchannel "
"%04x\n", cdev->private->dev_id.devno,
sch->schid.sch_no);
- if (!ccw_device_notify(cdev, CIO_NO_PATH))
+ if (ccw_device_notify(cdev, CIO_NO_PATH) != NOTIFY_OK)
ccw_device_sched_todo(cdev, CDEV_TODO_UNREG);
else
ccw_device_set_disconnected(cdev);
@@ -586,7 +609,7 @@
static void ccw_device_generic_notoper(struct ccw_device *cdev,
enum dev_event dev_event)
{
- if (!ccw_device_notify(cdev, CIO_GONE))
+ if (ccw_device_notify(cdev, CIO_GONE) != NOTIFY_OK)
ccw_device_sched_todo(cdev, CDEV_TODO_UNREG);
else
ccw_device_set_disconnected(cdev);
Index: quilt-2.6/drivers/s390/cio/device.h
===================================================================
--- quilt-2.6.orig/drivers/s390/cio/device.h 2010-02-24 09:44:23.000000000 +0100
+++ quilt-2.6/drivers/s390/cio/device.h 2010-02-24 09:44:26.000000000 +0100
@@ -4,7 +4,7 @@
#include <asm/ccwdev.h>
#include <asm/atomic.h>
#include <linux/wait.h>
-
+#include <linux/notifier.h>
#include "io_sch.h"

/*


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