s390/qdio: make thinint registration symmetric

tiqdio_add_device() adds the device to the tiq_list of eligible targets
for a data IRQ, which gets walked on each QDIO Adapter Interrupt to
inspect their DSCIs.

But currently the tiqdio_add_device() / tiqdio_remove_device() calls
are not symmetric - the device is removed within qdio_shutdown(),
but only added by qdio_activate().
So depending on the call sequence and encountered errors, we might
be trying to remove a list entry in qdio_shutdown() that was never even
added to the list. This required additional INIT_LIST_HEAD() calls to
ensure that the list entry was always in a consistent state.

All drivers now fence the IRQ delivery via qdio_start_irq() /
qdio_stop_irq(), so we can nicely integrate this tiq_list management
with the other steps needed for QDIO Adapter IRQ (de-)registration
(qdio_establish_thinint() / qdio_shutdown_thinint()).
As the naming suggests these get called during qdio_establish() and
qdio_shutdown(), with proper symmetry and roll-back after errors.

With this we longer need to worry about misplaced list removals, and
thus can clean up the list API abuse (INIT_LIST_HEAD() should not be
called on list entries).

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>

1 files changed, 0 insertions, 5 deletions

diff --git a/drivers/s390/cio/qdio_main.c b/drivers/s390/cio/qdio_main.c
index 2cc489c9f986..3b1e8ed4ba14 100644
--- a/drivers/s390/cio/qdio_main.c
+++ b/drivers/s390/cio/qdio_main.c
@@ -986,7 +986,6 @@ int qdio_shutdown(struct ccw_device *cdev, int how)
 	 */
 	qdio_set_state(irq_ptr, QDIO_IRQ_STATE_STOPPED);
 
-	tiqdio_remove_device(irq_ptr);
 	qdio_shutdown_queues(irq_ptr);
 	qdio_shutdown_debug_entries(irq_ptr);
 
@@ -1104,7 +1103,6 @@ int qdio_allocate(struct ccw_device *cdev, unsigned int no_input_qs,
 	if (rc)
 		goto err_queues;
 
-	INIT_LIST_HEAD(&irq_ptr->entry);
 	cdev->private->qdio_data = irq_ptr;
 	qdio_set_state(irq_ptr, QDIO_IRQ_STATE_INACTIVE);
 	return 0;
@@ -1287,9 +1285,6 @@ int qdio_activate(struct ccw_device *cdev)
 		goto out;
 	}
 
-	if (is_thinint_irq(irq_ptr))
-		tiqdio_add_device(irq_ptr);
-
 	/* wait for subchannel to become active */
 	msleep(5);