s390/cio: reorder initialization of ccw consoles

Drivers for ccw consoles use ccw_device_probe_console to receive
an initialized ccw device which is already enabled for interrupts.
After that the device driver does the initialization of its private
data. This can race with unsolicited interrupts which can happen
once the device is enabled for interrupts.

Split ccw_device_probe_console into ccw_device_create_console and
ccw_device_enable_console and reorder the initialization of the ccw
console drivers.

While at it mark these functions as __init.

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

4 files changed, 35 insertions, 15 deletions

diff --git a/arch/s390/include/asm/ccwdev.h b/arch/s390/include/asm/ccwdev.h
index 31b5ca8f8c3d..a9c2c0686177 100644
--- a/arch/s390/include/asm/ccwdev.h
+++ b/arch/s390/include/asm/ccwdev.h
@@ -219,7 +219,9 @@ extern void ccw_device_get_id(struct ccw_device *, struct ccw_dev_id *);
 #define to_ccwdev(n) container_of(n, struct ccw_device, dev)
 #define to_ccwdrv(n) container_of(n, struct ccw_driver, driver)
 
-extern struct ccw_device *ccw_device_probe_console(struct ccw_driver *);
+extern struct ccw_device *ccw_device_create_console(struct ccw_driver *);
+extern void ccw_device_destroy_console(struct ccw_device *);
+extern int ccw_device_enable_console(struct ccw_device *);
 extern void ccw_device_wait_idle(struct ccw_device *);
 extern int ccw_device_force_console(struct ccw_device *);
 
diff --git a/drivers/s390/char/con3215.c b/drivers/s390/char/con3215.c
index bb86494e2b7b..5af7f0bd6125 100644
--- a/drivers/s390/char/con3215.c
+++ b/drivers/s390/char/con3215.c
@@ -922,7 +922,7 @@ static int __init con3215_init(void)
 		raw3215_freelist = req;
 	}
 
-	cdev = ccw_device_probe_console(&raw3215_ccw_driver);
+	cdev = ccw_device_create_console(&raw3215_ccw_driver);
 	if (IS_ERR(cdev))
 		return -ENODEV;
 
@@ -932,6 +932,12 @@ static int __init con3215_init(void)
 	cdev->handler = raw3215_irq;
 
 	raw->flags |= RAW3215_FIXED;
+	if (ccw_device_enable_console(cdev)) {
+		ccw_device_destroy_console(cdev);
+		raw3215_free_info(raw);
+		raw3215[0] = NULL;
+		return -ENODEV;
+	}
 
 	/* Request the console irq */
 	if (raw3215_startup(raw) != 0) {
diff --git a/drivers/s390/char/raw3270.c b/drivers/s390/char/raw3270.c
index de2c0483949f..041c65bc7bb1 100644
--- a/drivers/s390/char/raw3270.c
+++ b/drivers/s390/char/raw3270.c
@@ -790,7 +790,7 @@ struct raw3270 __init *raw3270_setup_console(void)
 	char *ascebc;
 	int rc;
 
-	cdev = ccw_device_probe_console(&raw3270_ccw_driver);
+	cdev = ccw_device_create_console(&raw3270_ccw_driver);
 	if (IS_ERR(cdev))
 		return ERR_CAST(cdev);
 
@@ -800,6 +800,13 @@ struct raw3270 __init *raw3270_setup_console(void)
 	if (rc)
 		return ERR_PTR(rc);
 	set_bit(RAW3270_FLAGS_CONSOLE, &rp->flags);
+
+	rc = ccw_device_enable_console(cdev);
+	if (rc) {
+		ccw_device_destroy_console(cdev);
+		return ERR_PTR(rc);
+	}
+
 	spin_lock_irqsave(get_ccwdev_lock(rp->cdev), flags);
 	do {
 		__raw3270_reset_device(rp);
diff --git a/drivers/s390/cio/device.c b/drivers/s390/cio/device.c
index 4283dd3cdd49..da431992fd8e 100644
--- a/drivers/s390/cio/device.c
+++ b/drivers/s390/cio/device.c
@@ -1572,11 +1572,14 @@ out:
 }
 
 #ifdef CONFIG_CCW_CONSOLE
-static int ccw_device_console_enable(struct ccw_device *cdev,
-				     struct subchannel *sch)
+int __init ccw_device_enable_console(struct ccw_device *cdev)
 {
+	struct subchannel *sch = to_subchannel(cdev->dev.parent);
 	int rc;
 
+	if (!cdev->drv || !cdev->handler)
+		return -EINVAL;
+
 	io_subchannel_init_fields(sch);
 	rc = cio_commit_config(sch);
 	if (rc)
@@ -1609,12 +1612,11 @@ out_unlock:
 	return rc;
 }
 
-struct ccw_device *ccw_device_probe_console(struct ccw_driver *drv)
+struct ccw_device * __init ccw_device_create_console(struct ccw_driver *drv)
 {
 	struct io_subchannel_private *io_priv;
 	struct ccw_device *cdev;
 	struct subchannel *sch;
-	int ret;
 
 	sch = cio_probe_console();
 	if (IS_ERR(sch))
@@ -1633,17 +1635,20 @@ struct ccw_device *ccw_device_probe_console(struct ccw_driver *drv)
 	}
 	cdev->drv = drv;
 	set_io_private(sch, io_priv);
-	ret = ccw_device_console_enable(cdev, sch);
-	if (ret) {
-		set_io_private(sch, NULL);
-		put_device(&sch->dev);
-		put_device(&cdev->dev);
-		kfree(io_priv);
-		return ERR_PTR(ret);
-	}
 	return cdev;
 }
 
+void __init ccw_device_destroy_console(struct ccw_device *cdev)
+{
+	struct subchannel *sch = to_subchannel(cdev->dev.parent);
+	struct io_subchannel_private *io_priv = to_io_private(sch);
+
+	set_io_private(sch, NULL);
+	put_device(&sch->dev);
+	put_device(&cdev->dev);
+	kfree(io_priv);
+}
+
 /**
  * ccw_device_wait_idle() - busy wait for device to become idle
  * @cdev: ccw device