2008-02-09 12:05:48

by Martin Schwidefsky

[permalink] [raw]
Subject: [patch 06/11] qdio: avoid hang when establishing qdio queues

From: Ursula Braun <[email protected]>

If qdio establish runs in parallel with a channel error,
ccw_device_start_timeout may not trigger the qdio_timeout_handler.
In this case neither QDIO_IRQ_STATE_ESTABLISHED nor
QDIO_IRQ_STATE_ERR is reached and the following wait_event hangs
forever.
Solution: do not make use of the timeout option with
ccw_device_start, but add a timeout to the following wait_event.

Signed-off-by: Ursula Braun <[email protected]>
Signed-off-by: Martin Schwidefsky <[email protected]>
---

drivers/s390/cio/qdio.c | 18 ++++++++----------
1 file changed, 8 insertions(+), 10 deletions(-)

Index: quilt-2.6/drivers/s390/cio/qdio.c
===================================================================
--- quilt-2.6.orig/drivers/s390/cio/qdio.c
+++ quilt-2.6/drivers/s390/cio/qdio.c
@@ -3189,13 +3189,11 @@ qdio_establish(struct qdio_initialize *i
spin_lock_irqsave(get_ccwdev_lock(cdev),saveflags);

ccw_device_set_options_mask(cdev, 0);
- result=ccw_device_start_timeout(cdev,&irq_ptr->ccw,
- QDIO_DOING_ESTABLISH,0, 0,
- QDIO_ESTABLISH_TIMEOUT);
+ result = ccw_device_start(cdev, &irq_ptr->ccw,
+ QDIO_DOING_ESTABLISH, 0, 0);
if (result) {
- result2=ccw_device_start_timeout(cdev,&irq_ptr->ccw,
- QDIO_DOING_ESTABLISH,0,0,
- QDIO_ESTABLISH_TIMEOUT);
+ result2 = ccw_device_start(cdev, &irq_ptr->ccw,
+ QDIO_DOING_ESTABLISH, 0, 0);
sprintf(dbf_text,"eq:io%4x",result);
QDIO_DBF_TEXT2(1,setup,dbf_text);
if (result2) {
@@ -3219,10 +3217,10 @@ qdio_establish(struct qdio_initialize *i
return result;
}

- /* Timeout is cared for already by using ccw_device_start_timeout(). */
- wait_event_interruptible(cdev->private->wait_q,
- irq_ptr->state == QDIO_IRQ_STATE_ESTABLISHED ||
- irq_ptr->state == QDIO_IRQ_STATE_ERR);
+ wait_event_interruptible_timeout(cdev->private->wait_q,
+ irq_ptr->state == QDIO_IRQ_STATE_ESTABLISHED ||
+ irq_ptr->state == QDIO_IRQ_STATE_ERR,
+ QDIO_ESTABLISH_TIMEOUT);

if (irq_ptr->state == QDIO_IRQ_STATE_ESTABLISHED)
result = 0;

--
blue skies,
Martin.

"Reality continues to ruin my life." - Calvin.