[SRU][Cosmic][Disco][PATCH 1/1] s390/zcrypt: reinit ap queue state machine during device probe

Joseph Salisbury joseph.salisbury at canonical.com
Fri Dec 14 16:32:06 UTC 2018


From: Harald Freudenberger <freude at linux.ibm.com>

BugLink: https://bugs.launchpad.net/bugs/1805414

Until the vfio-ap driver came into live there was a well known
agreement about the way how ap devices are initialized and their
states when the driver's probe function is called.

However, the vfio device driver when receiving an ap queue device does
additional resets thereby removing the registration for interrupts for
the ap device done by the ap bus core code. So when later the vfio
driver releases the device and one of the default zcrypt drivers takes
care of the device the interrupt registration needs to get
renewed. The current code does no renew and result is that requests
send into such a queue will never see a reply processed - the
application hangs.

This patch adds a function which resets the aq queue state machine for
the ap queue device and triggers the walk through the initial states
(which are reset and registration for interrupts). This function is
now called before the driver's probe function is invoked.

When the association between driver and device is released, the
driver's remove function is called. The current implementation calls a
ap queue function ap_queue_remove(). This invokation has been moved to
the ap bus function to make the probe / remove pair for ap bus and
drivers more symmetric.

Fixes: 7e0bdbe5c21c ("s390/zcrypt: AP bus support for alternate driver(s)")
Cc: stable at vger.kernel.org # 4.19+
Signed-off-by: Harald Freudenberger <freude at linux.ibm.com>
Reviewd-by: Tony Krowiak <akrowiak at linux.ibm.com>
Reviewd-by: Martin Schwidefsky <schwidefsky at de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky at de.ibm.com>
(cherry picked from commit 104f708fd1241b22f808bdf066ab67dc5a051de5)
Signed-off-by: Joseph Salisbury <joseph.salisbury at canonical.com>
---
 drivers/s390/crypto/ap_bus.c        |  8 ++++----
 drivers/s390/crypto/ap_bus.h        |  1 +
 drivers/s390/crypto/ap_queue.c      | 15 +++++++++++++++
 drivers/s390/crypto/zcrypt_cex2a.c  |  1 -
 drivers/s390/crypto/zcrypt_cex4.c   |  1 -
 drivers/s390/crypto/zcrypt_pcixcc.c |  1 -
 6 files changed, 20 insertions(+), 7 deletions(-)

diff --git a/drivers/s390/crypto/ap_bus.c b/drivers/s390/crypto/ap_bus.c
index 4521b21..84595b2 100644
--- a/drivers/s390/crypto/ap_bus.c
+++ b/drivers/s390/crypto/ap_bus.c
@@ -795,6 +795,8 @@ static int ap_device_probe(struct device *dev)
 		drvres = ap_drv->flags & AP_DRIVER_FLAG_DEFAULT;
 		if (!!devres != !!drvres)
 			return -ENODEV;
+		/* (re-)init queue's state machine */
+		ap_queue_reinit_state(to_ap_queue(dev));
 	}
 
 	/* Add queue/card to list of active queues/cards */
@@ -827,6 +829,8 @@ static int ap_device_remove(struct device *dev)
 	struct ap_device *ap_dev = to_ap_dev(dev);
 	struct ap_driver *ap_drv = ap_dev->drv;
 
+	if (is_queue_dev(dev))
+		ap_queue_remove(to_ap_queue(dev));
 	if (ap_drv->remove)
 		ap_drv->remove(ap_dev);
 
@@ -1484,10 +1488,6 @@ static void ap_scan_bus(struct work_struct *unused)
 			aq->ap_dev.device.parent = &ac->ap_dev.device;
 			dev_set_name(&aq->ap_dev.device,
 				     "%02x.%04x", id, dom);
-			/* Start with a device reset */
-			spin_lock_bh(&aq->lock);
-			ap_wait(ap_sm_event(aq, AP_EVENT_POLL));
-			spin_unlock_bh(&aq->lock);
 			/* Register device */
 			rc = device_register(&aq->ap_dev.device);
 			if (rc) {
diff --git a/drivers/s390/crypto/ap_bus.h b/drivers/s390/crypto/ap_bus.h
index 7c3c077..5ea5eaf 100644
--- a/drivers/s390/crypto/ap_bus.h
+++ b/drivers/s390/crypto/ap_bus.h
@@ -252,6 +252,7 @@ struct ap_queue *ap_queue_create(ap_qid_t qid, int device_type);
 void ap_queue_remove(struct ap_queue *aq);
 void ap_queue_suspend(struct ap_device *ap_dev);
 void ap_queue_resume(struct ap_device *ap_dev);
+void ap_queue_reinit_state(struct ap_queue *aq);
 
 struct ap_card *ap_card_create(int id, int queue_depth, int raw_device_type,
 			       int comp_device_type, unsigned int functions);
diff --git a/drivers/s390/crypto/ap_queue.c b/drivers/s390/crypto/ap_queue.c
index c3e9e9f..7450b3b 100644
--- a/drivers/s390/crypto/ap_queue.c
+++ b/drivers/s390/crypto/ap_queue.c
@@ -738,5 +738,20 @@ void ap_queue_remove(struct ap_queue *aq)
 {
 	ap_flush_queue(aq);
 	del_timer_sync(&aq->timeout);
+
+	/* reset with zero, also clears irq registration */
+	spin_lock_bh(&aq->lock);
+	ap_zapq(aq->qid);
+	aq->state = AP_STATE_BORKED;
+	spin_unlock_bh(&aq->lock);
 }
 EXPORT_SYMBOL(ap_queue_remove);
+
+void ap_queue_reinit_state(struct ap_queue *aq)
+{
+	spin_lock_bh(&aq->lock);
+	aq->state = AP_STATE_RESET_START;
+	ap_wait(ap_sm_event(aq, AP_EVENT_POLL));
+	spin_unlock_bh(&aq->lock);
+}
+EXPORT_SYMBOL(ap_queue_reinit_state);
diff --git a/drivers/s390/crypto/zcrypt_cex2a.c b/drivers/s390/crypto/zcrypt_cex2a.c
index f4ae5fa..ff17a00 100644
--- a/drivers/s390/crypto/zcrypt_cex2a.c
+++ b/drivers/s390/crypto/zcrypt_cex2a.c
@@ -198,7 +198,6 @@ static void zcrypt_cex2a_queue_remove(struct ap_device *ap_dev)
 	struct ap_queue *aq = to_ap_queue(&ap_dev->device);
 	struct zcrypt_queue *zq = aq->private;
 
-	ap_queue_remove(aq);
 	if (zq)
 		zcrypt_queue_unregister(zq);
 }
diff --git a/drivers/s390/crypto/zcrypt_cex4.c b/drivers/s390/crypto/zcrypt_cex4.c
index 35d58db..2a42e59 100644
--- a/drivers/s390/crypto/zcrypt_cex4.c
+++ b/drivers/s390/crypto/zcrypt_cex4.c
@@ -273,7 +273,6 @@ static void zcrypt_cex4_queue_remove(struct ap_device *ap_dev)
 	struct ap_queue *aq = to_ap_queue(&ap_dev->device);
 	struct zcrypt_queue *zq = aq->private;
 
-	ap_queue_remove(aq);
 	if (zq)
 		zcrypt_queue_unregister(zq);
 }
diff --git a/drivers/s390/crypto/zcrypt_pcixcc.c b/drivers/s390/crypto/zcrypt_pcixcc.c
index 94d9f72..baa683c 100644
--- a/drivers/s390/crypto/zcrypt_pcixcc.c
+++ b/drivers/s390/crypto/zcrypt_pcixcc.c
@@ -276,7 +276,6 @@ static void zcrypt_pcixcc_queue_remove(struct ap_device *ap_dev)
 	struct ap_queue *aq = to_ap_queue(&ap_dev->device);
 	struct zcrypt_queue *zq = aq->private;
 
-	ap_queue_remove(aq);
 	if (zq)
 		zcrypt_queue_unregister(zq);
 }
-- 
2.7.4




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