[PATCH 4.4 025/158] s390/qdio: handle PENDING state for QEBSM devices

Greg Kroah-Hartman
2019-08-02T10:06:51Z

[ Upstream commit 04310324c6f482921c071444833e70fe861b73d9 ]

When a CQ-enabled device uses QEBSM for SBAL state inspection,
get_buf_states() can return the PENDING state for an Output Queue.
get_outbound_buffer_frontier() isn't prepared for this, and any PENDING
buffer will permanently stall all further completion processing on this
Queue.

This isn't a concern for non-QEBSM devices, as get_buf_states() for such
devices will manually turn PENDING buffers into EMPTY ones.

Fixes: 104ea556ee7f ("qdio: support asynchronous delivery of storage blocks")
Signed-off-by: Julian Wiedmann <jwi@linux.ibm.com>
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/s390/cio/qdio_main.c | 1 +
1 file changed, 1 insertion(+)

diff --git a/drivers/s390/cio/qdio_main.c b/drivers/s390/cio/qdio_main.c
index d64b401f3d05..8d7fc3b6ca63 100644
--- a/drivers/s390/cio/qdio_main.c
+++ b/drivers/s390/cio/qdio_main.c
@@ -752,6 +752,7 @@ static int get_outbound_buffer_frontier(struct qdio_q *q)

switch (state) {
case SLSB_P_OUTPUT_EMPTY:
+ case SLSB_P_OUTPUT_PENDING:
/* the adapter got it */
DBF_DEV_EVENT(DBF_INFO, q->irq_ptr,
"out empty:%1d %02x", q->nr, count);
--
2.20.1