linux-kernel - [PATCH 4.19 19/92] iio: dac: ad5592r: fix unbalanced mutex unlocks in ad5592r_read

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Message-Id: <20200820091538.559679156@linuxfoundation.org>
Date:   Thu, 20 Aug 2020 11:21:04 +0200
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org,
        Charles Stanhope <charles.stanhope@...il.com>,
        Alexandru Ardelean <alexandru.ardelean@...log.com>,
        Stable@...r.kernel.org,
        Jonathan Cameron <Jonathan.Cameron@...wei.com>
Subject: [PATCH 4.19 19/92] iio: dac: ad5592r: fix unbalanced mutex unlocks in ad5592r_read_raw()

From: Alexandru Ardelean <alexandru.ardelean@...log.com>

commit 65afb0932a81c1de719ceee0db0b276094b10ac8 upstream.

There are 2 exit paths where the lock isn't held, but try to unlock the
mutex when exiting. In these places we should just return from the
function.

A neater approach would be to cleanup the ad5592r_read_raw(), but that
would make this patch more difficult to backport to stable versions.

Fixes 56ca9db862bf3: ("iio: dac: Add support for the AD5592R/AD5593R ADCs/DACs")
Reported-by: Charles Stanhope <charles.stanhope@...il.com>
Signed-off-by: Alexandru Ardelean <alexandru.ardelean@...log.com>
Cc: <Stable@...r.kernel.org>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@...wei.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>

---
 drivers/iio/dac/ad5592r-base.c |    4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

--- a/drivers/iio/dac/ad5592r-base.c
+++ b/drivers/iio/dac/ad5592r-base.c
@@ -417,7 +417,7 @@ static int ad5592r_read_raw(struct iio_d
 			s64 tmp = *val * (3767897513LL / 25LL);
 			*val = div_s64_rem(tmp, 1000000000LL, val2);
 
-			ret = IIO_VAL_INT_PLUS_MICRO;
+			return IIO_VAL_INT_PLUS_MICRO;
 		} else {
 			int mult;
 
@@ -448,7 +448,7 @@ static int ad5592r_read_raw(struct iio_d
 		ret =  IIO_VAL_INT;
 		break;
 	default:
-		ret = -EINVAL;
+		return -EINVAL;
 	}
 
 unlock: