From 1e4a382fdc0ba8d1a85b758c0811de3a3631085e Mon Sep 17 00:00:00 2001 From: Julian Wiedmann Date: Mon, 21 Nov 2016 13:37:48 +0100 Subject: [PATCH] s390/qdio: clear DSCI prior to scanning multiple input queues For devices with multiple input queues, tiqdio_call_inq_handlers() iterates over all input queues and clears the device's DSCI during each iteration. If the DSCI is re-armed during one of the later iterations, we therefore do not scan the previous queues again. The re-arming also raises a new adapter interrupt. But its handler does not trigger a rescan for the device, as the DSCI has already been erroneously cleared. This can result in queue stalls on devices with multiple input queues. Fix it by clearing the DSCI just once, prior to scanning the queues. As the code is moved in front of the loop, we also need to access the DSCI directly (ie irq->dsci) instead of going via each queue's parent pointer to the same irq. This is not a functional change, and a follow-up patch will clean up the other users. In practice, this bug only affects CQ-enabled HiperSockets devices, ie. devices with sysfs-attribute "hsuid" set. Setting a hsuid is needed for AF_IUCV socket applications that use HiperSockets communication. Fixes: 104ea556ee7f ("qdio: support asynchronous delivery of storage blocks") Cc: # v3.2+ Reviewed-by: Ursula Braun Signed-off-by: Julian Wiedmann Signed-off-by: Martin Schwidefsky --- drivers/s390/cio/qdio_thinint.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) diff --git a/drivers/s390/cio/qdio_thinint.c b/drivers/s390/cio/qdio_thinint.c index 5d06253c2a7a..30e9fbbff051 100644 --- a/drivers/s390/cio/qdio_thinint.c +++ b/drivers/s390/cio/qdio_thinint.c @@ -147,11 +147,11 @@ static inline void tiqdio_call_inq_handlers(struct qdio_irq *irq) struct qdio_q *q; int i; - for_each_input_queue(irq, q, i) { - if (!references_shared_dsci(irq) && - has_multiple_inq_on_dsci(irq)) - xchg(q->irq_ptr->dsci, 0); + if (!references_shared_dsci(irq) && + has_multiple_inq_on_dsci(irq)) + xchg(irq->dsci, 0); + for_each_input_queue(irq, q, i) { if (q->u.in.queue_start_poll) { /* skip if polling is enabled or already in work */ if (test_and_set_bit(QDIO_QUEUE_IRQS_DISABLED,