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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,
        Srinivas Kandagatla <srinivas.kandagatla@linaro.org>,
        Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>,
        Sanyog Kale <sanyog.r.kale@intel.com>,
        Vinod Koul <vkoul@kernel.org>, Sasha Levin <sashal@kernel.org>
Subject: [PATCH 5.1 031/138] soundwire: stream: fix bad unlock balance
Date:   Fri, 12 Jul 2019 14:18:15 +0200
Message-Id: <20190712121629.888401834@linuxfoundation.org>
In-Reply-To: <20190712121628.731888964@linuxfoundation.org>
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[ Upstream commit 9315d904c7e8f38886e2820fa6cb8d0fa723ea21 ]

the msg lock is taken for multi-link cases only but released
unconditionally, leading to an unlock balance warning for single-link usages
This patch fixes this.

 =====================================
 WARNING: bad unlock balance detected!
 5.1.0-16506-gc1c383a6f0a2-dirty #1523 Tainted: G        W
 -------------------------------------
 aplay/2954 is trying to release lock (&bus->msg_lock) at:
 do_bank_switch+0x21c/0x480
 but there are no more locks to release!

Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Acked-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Acked-by: Sanyog Kale <sanyog.r.kale@intel.com>
[vkoul: edited the change log as suggested by Pierre]
Signed-off-by: Vinod Koul <vkoul@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/soundwire/stream.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/soundwire/stream.c b/drivers/soundwire/stream.c
index 00618de2ee12..794ced434cf2 100644
--- a/drivers/soundwire/stream.c
+++ b/drivers/soundwire/stream.c
@@ -805,7 +805,8 @@ static int do_bank_switch(struct sdw_stream_runtime *stream)
 			goto error;
 		}
 
-		mutex_unlock(&bus->msg_lock);
+		if (bus->multi_link)
+			mutex_unlock(&bus->msg_lock);
 	}
 
 	return ret;
-- 
2.20.1