Fix oinkmaster patch.

[people/pmueller/ipfire-2.x.git] / src / patches / suse-2.6.27.39 / patches.arch / s390-11-07-qdio_kill_tasklets.patch

From: Gerald Schaefer <geraldsc@de.ibm.com>
Subject: qdio: proper kill of qdio tasklets
References: bnc#484767,LTC#52206

Symptom:     kernel BUG at kernel/softirq.c:392!
Problem:     The queue tasklets were stopped with tasklet_disable. Although
             tasklet_disable prevents the tasklet from beeing executed it is
             still possible that a tasklet is scheduled on a CPU at that point.
             A following qdio_establish calls tasklet_init which clears the
             tasklet count and the tasklet state leading to the oops.
Solution:    Use tasklet_kill instead of tasklet_disbale. Since
             tasklet_schedule must not be called after tasklet_kill use the
             QDIO_IRQ_STATE_STOPPED to inidicate that a queue is going down
             and prevent further tasklet schedules in that case.

Acked-by: John Jolly <jjolly@suse.de>
---
 drivers/s390/cio/qdio_main.c    |   35 ++++++++++++++++++++++++-----------
 drivers/s390/cio/qdio_thinint.c |    8 ++++----
 2 files changed, 28 insertions(+), 15 deletions(-)

Index: linux-sles11/drivers/s390/cio/qdio_main.c
===================================================================
--- linux-sles11.orig/drivers/s390/cio/qdio_main.c
+++ linux-sles11/drivers/s390/cio/qdio_main.c
@@ -760,21 +760,17 @@ static void __qdio_outbound_processing(s
 	if (qdio_outbound_q_moved(q))
 		qdio_kick_outbound_handler(q);
 
-	if (queue_type(q) == QDIO_ZFCP_QFMT) {
+	if (queue_type(q) == QDIO_ZFCP_QFMT)
 		if (!pci_out_supported(q) && !qdio_outbound_q_done(q))
-			tasklet_schedule(&q->tasklet);
-		return;
-	}
+			goto sched;
 
 	/* bail out for HiperSockets unicast queues */
 	if (queue_type(q) == QDIO_IQDIO_QFMT && !multicast_outbound(q))
 		return;
 
 	if ((queue_type(q) == QDIO_IQDIO_QFMT) &&
-	    (atomic_read(&q->nr_buf_used)) > QDIO_IQDIO_POLL_LVL) {
-		tasklet_schedule(&q->tasklet);
-		return;
-	}
+	    (atomic_read(&q->nr_buf_used)) > QDIO_IQDIO_POLL_LVL)
+		goto sched;
 
 	if (q->u.out.pci_out_enabled)
 		return;
@@ -792,6 +788,12 @@ static void __qdio_outbound_processing(s
 			qdio_perf_stat_inc(&perf_stats.debug_tl_out_timer);
 		}
 	}
+	return;
+
+sched:
+	if (unlikely(q->irq_ptr->state == QDIO_IRQ_STATE_STOPPED))
+		return;
+	tasklet_schedule(&q->tasklet);
 }
 
 /* outbound tasklet */
@@ -804,6 +806,9 @@ void qdio_outbound_processing(unsigned l
 void qdio_outbound_timer(unsigned long data)
 {
 	struct qdio_q *q = (struct qdio_q *)data;
+
+	if (unlikely(q->irq_ptr->state == QDIO_IRQ_STATE_STOPPED))
+		return;
 	tasklet_schedule(&q->tasklet);
 }
 
@@ -845,6 +850,9 @@ static void qdio_int_handler_pci(struct 
 	int i;
 	struct qdio_q *q;
 
+	if (unlikely(irq_ptr->state == QDIO_IRQ_STATE_STOPPED))
+		return;
+
 	qdio_perf_stat_inc(&perf_stats.pci_int);
 
 	for_each_input_queue(irq_ptr, q, i)
@@ -1072,11 +1080,11 @@ static void qdio_shutdown_queues(struct 
 	int i;
 
 	for_each_input_queue(irq_ptr, q, i)
-		tasklet_disable(&q->tasklet);
+		tasklet_kill(&q->tasklet);
 
 	for_each_output_queue(irq_ptr, q, i) {
-		tasklet_disable(&q->tasklet);
 		del_timer(&q->u.out.timer);
+		tasklet_kill(&q->tasklet);
 	}
 }
 
@@ -1107,6 +1115,12 @@ int qdio_shutdown(struct ccw_device *cde
 		return 0;
 	}
 
+	/*
+	 * Indicate that the device is going down. Scheduling the queue
+	 * tasklets is forbidden from here on.
+	 */
+	qdio_set_state(irq_ptr, QDIO_IRQ_STATE_STOPPED);
+
 	tiqdio_remove_input_queues(irq_ptr);
 	qdio_shutdown_queues(cdev);
 	qdio_shutdown_debug_entries(irq_ptr, cdev);
@@ -1526,7 +1540,6 @@ static int handle_outbound(struct qdio_q
 		qdio_perf_stat_inc(&perf_stats.fast_requeue);
 	}
 out:
-	/* Fixme: could wait forever if called from process context */
 	tasklet_schedule(&q->tasklet);
 	return rc;
 }
Index: linux-sles11/drivers/s390/cio/qdio_thinint.c
===================================================================
--- linux-sles11.orig/drivers/s390/cio/qdio_thinint.c
+++ linux-sles11/drivers/s390/cio/qdio_thinint.c
@@ -101,7 +101,6 @@ void tiqdio_add_input_queues(struct qdio
 		list_add_rcu(&q->entry, &tiq_list);
 	mutex_unlock(&tiq_list_lock);
 	xchg(irq_ptr->dsci, 1);
-	tasklet_schedule(&tiqdio_tasklet);
 }
 
 /*
@@ -159,7 +158,6 @@ static void __tiqdio_inbound_processing(
 	 */
 	qdio_check_outbound_after_thinint(q);
 
-again:
 	if (!qdio_inbound_q_moved(q))
 		return;
 
@@ -167,7 +165,8 @@ again:
 
 	if (!tiqdio_inbound_q_done(q)) {
 		qdio_perf_stat_inc(&perf_stats.thinint_inbound_loop);
-		goto again;
+		if (likely(q->irq_ptr->state != QDIO_IRQ_STATE_STOPPED))
+			tasklet_schedule(&q->tasklet);
 	}
 
 	qdio_stop_polling(q);
@@ -177,7 +176,8 @@ again:
 	 */
 	if (!tiqdio_inbound_q_done(q)) {
 		qdio_perf_stat_inc(&perf_stats.thinint_inbound_loop2);
-		goto again;
+		if (likely(q->irq_ptr->state != QDIO_IRQ_STATE_STOPPED))
+			tasklet_schedule(&q->tasklet);
 	}
 }