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[S390] qdio: avoid hang when establishing qdio queues
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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 <braunu@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
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Ursula Braun authored and Martin Schwidefsky committed Feb 9, 2008
1 parent 522d8dc commit bf3f837
Showing 1 changed file with 8 additions and 10 deletions.
18 changes: 8 additions & 10 deletions drivers/s390/cio/qdio.c
Original file line number Diff line number Diff line change
Expand Up @@ -3189,13 +3189,11 @@ qdio_establish(struct qdio_initialize *init_data)
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) {
Expand All @@ -3219,10 +3217,10 @@ qdio_establish(struct qdio_initialize *init_data)
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;
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