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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, Julian Wiedmann <jwi@linux.ibm.com>,
        Heiko Carstens <heiko.carstens@de.ibm.com>,
        Sasha Levin <sashal@kernel.org>
Subject: [PATCH 5.2 074/413] s390/qdio: handle PENDING state for QEBSM devices
Date:   Wed, 24 Jul 2019 21:16:05 +0200
Message-Id: <20190724191740.398055580@linuxfoundation.org>
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[ 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 7b7620de2acd..730c4e68094b 100644
--- a/drivers/s390/cio/qdio_main.c
+++ b/drivers/s390/cio/qdio_main.c
@@ -736,6 +736,7 @@ static int get_outbound_buffer_frontier(struct qdio_q *q, unsigned int start)
 
 	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