diff mbox series

[5.7,138/477] s390/qdio: consistently restore the IRQ handler

Message ID 20200623195414.129419213@linuxfoundation.org
State New
Headers show
Series None | expand

Commit Message

Greg Kroah-Hartman June 23, 2020, 7:52 p.m. UTC 
From: Julian Wiedmann <jwi@linux.ibm.com>

[ Upstream commit 7b942b4be971d49cb185ce4690d7fbf94636e88a ]

For rolling back after an error, qdio_establish() calls qdio_shutdown().
If the error occurs early enough, then the qdio_irq's state still is
QDIO_IRQ_STATE_INACTIVE and qdio_shutdown() does nothing.

But at _any_ point where qdio_establish() bails out in this way,
qdio_setup_irq() will have already replaced the IRQ handler. This then
won't be restored after an early error, and the device can end up being
returned to the device driver with qdio's IRQ handler still installed.

Slightly reorder qdio_setup_irq() so we can be 100% sure that the IRQ
handler was replaced. Then fix the bug in qdio_establish() by calling a
helper that rolls back only the IRQ handler modification.

Also use the new helper in qdio_shutdown() to keep things in sync, and
slightly clean up the locking while doing so.
This makes minor semantical changes, but holding setup_mutex gives us
sufficient leeway to eg. pull qdio_shutdown_thinint() outside of the
ccwdev lock's scope.

Fixes: 779e6e1c724d ("[S390] qdio: new qdio driver.")
Signed-off-by: Julian Wiedmann <jwi@linux.ibm.com>
Reviewed-by: Benjamin Block <bblock@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/s390/cio/qdio.h       |  1 +
 drivers/s390/cio/qdio_main.c  | 18 +++++-------------
 drivers/s390/cio/qdio_setup.c | 20 ++++++++++++++++----
 3 files changed, 22 insertions(+), 17 deletions(-)
diff mbox series

Patch

diff --git a/drivers/s390/cio/qdio.h b/drivers/s390/cio/qdio.h
index b8453b5946794..3cf223bc1d5f4 100644
--- a/drivers/s390/cio/qdio.h
+++ b/drivers/s390/cio/qdio.h
@@ -389,6 +389,7 @@  int qdio_setup_get_ssqd(struct qdio_irq *irq_ptr,
 			struct subchannel_id *schid,
 			struct qdio_ssqd_desc *data);
 int qdio_setup_irq(struct qdio_irq *irq_ptr, struct qdio_initialize *init_data);
+void qdio_shutdown_irq(struct qdio_irq *irq);
 void qdio_print_subchannel_info(struct qdio_irq *irq_ptr);
 void qdio_release_memory(struct qdio_irq *irq_ptr);
 int qdio_setup_init(void);
diff --git a/drivers/s390/cio/qdio_main.c b/drivers/s390/cio/qdio_main.c
index bcc3ab14e72df..da5a111380201 100644
--- a/drivers/s390/cio/qdio_main.c
+++ b/drivers/s390/cio/qdio_main.c
@@ -1154,35 +1154,27 @@  int qdio_shutdown(struct ccw_device *cdev, int how)
 
 	/* cleanup subchannel */
 	spin_lock_irq(get_ccwdev_lock(cdev));
-
+	qdio_set_state(irq_ptr, QDIO_IRQ_STATE_CLEANUP);
 	if (how & QDIO_FLAG_CLEANUP_USING_CLEAR)
 		rc = ccw_device_clear(cdev, QDIO_DOING_CLEANUP);
 	else
 		/* default behaviour is halt */
 		rc = ccw_device_halt(cdev, QDIO_DOING_CLEANUP);
+	spin_unlock_irq(get_ccwdev_lock(cdev));
 	if (rc) {
 		DBF_ERROR("%4x SHUTD ERR", irq_ptr->schid.sch_no);
 		DBF_ERROR("rc:%4d", rc);
 		goto no_cleanup;
 	}
 
-	qdio_set_state(irq_ptr, QDIO_IRQ_STATE_CLEANUP);
-	spin_unlock_irq(get_ccwdev_lock(cdev));
 	wait_event_interruptible_timeout(cdev->private->wait_q,
 		irq_ptr->state == QDIO_IRQ_STATE_INACTIVE ||
 		irq_ptr->state == QDIO_IRQ_STATE_ERR,
 		10 * HZ);
-	spin_lock_irq(get_ccwdev_lock(cdev));
 
 no_cleanup:
 	qdio_shutdown_thinint(irq_ptr);
-
-	/* restore interrupt handler */
-	if ((void *)cdev->handler == (void *)qdio_int_handler) {
-		cdev->handler = irq_ptr->orig_handler;
-		cdev->private->intparm = 0;
-	}
-	spin_unlock_irq(get_ccwdev_lock(cdev));
+	qdio_shutdown_irq(irq_ptr);
 
 	qdio_set_state(irq_ptr, QDIO_IRQ_STATE_INACTIVE);
 	mutex_unlock(&irq_ptr->setup_mutex);
@@ -1352,8 +1344,8 @@  int qdio_establish(struct ccw_device *cdev,
 
 	rc = qdio_establish_thinint(irq_ptr);
 	if (rc) {
+		qdio_shutdown_irq(irq_ptr);
 		mutex_unlock(&irq_ptr->setup_mutex);
-		qdio_shutdown(cdev, QDIO_FLAG_CLEANUP_USING_CLEAR);
 		return rc;
 	}
 
@@ -1371,8 +1363,8 @@  int qdio_establish(struct ccw_device *cdev,
 	if (rc) {
 		DBF_ERROR("%4x est IO ERR", irq_ptr->schid.sch_no);
 		DBF_ERROR("rc:%4x", rc);
+		qdio_shutdown_irq(irq_ptr);
 		mutex_unlock(&irq_ptr->setup_mutex);
-		qdio_shutdown(cdev, QDIO_FLAG_CLEANUP_USING_CLEAR);
 		return rc;
 	}
 
diff --git a/drivers/s390/cio/qdio_setup.c b/drivers/s390/cio/qdio_setup.c
index 3083edd61f0c9..d12f094db056e 100644
--- a/drivers/s390/cio/qdio_setup.c
+++ b/drivers/s390/cio/qdio_setup.c
@@ -491,6 +491,12 @@  int qdio_setup_irq(struct qdio_irq *irq_ptr, struct qdio_initialize *init_data)
 
 	/* qdr, qib, sls, slsbs, slibs, sbales are filled now */
 
+	/* set our IRQ handler */
+	spin_lock_irq(get_ccwdev_lock(cdev));
+	irq_ptr->orig_handler = cdev->handler;
+	cdev->handler = qdio_int_handler;
+	spin_unlock_irq(get_ccwdev_lock(cdev));
+
 	/* get qdio commands */
 	ciw = ccw_device_get_ciw(cdev, CIW_TYPE_EQUEUE);
 	if (!ciw) {
@@ -506,12 +512,18 @@  int qdio_setup_irq(struct qdio_irq *irq_ptr, struct qdio_initialize *init_data)
 	}
 	irq_ptr->aqueue = *ciw;
 
-	/* set new interrupt handler */
+	return 0;
+}
+
+void qdio_shutdown_irq(struct qdio_irq *irq)
+{
+	struct ccw_device *cdev = irq->cdev;
+
+	/* restore IRQ handler */
 	spin_lock_irq(get_ccwdev_lock(cdev));
-	irq_ptr->orig_handler = cdev->handler;
-	cdev->handler = qdio_int_handler;
+	cdev->handler = irq->orig_handler;
+	cdev->private->intparm = 0;
 	spin_unlock_irq(get_ccwdev_lock(cdev));
-	return 0;
 }
 
 void qdio_print_subchannel_info(struct qdio_irq *irq_ptr)