linux-kernel - [PATCH AUTOSEL 5.2 51/59] drm/exynos: fix missing decrement of retry counter

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Date:   Tue,  6 Aug 2019 17:33:11 -0400
From:   Sasha Levin <sashal@...nel.org>
To:     linux-kernel@...r.kernel.org, stable@...r.kernel.org
Cc:     Colin Ian King <colin.king@...onical.com>,
        Inki Dae <inki.dae@...sung.com>,
        Sasha Levin <sashal@...nel.org>,
        dri-devel@...ts.freedesktop.org
Subject: [PATCH AUTOSEL 5.2 51/59] drm/exynos: fix missing decrement of retry counter

From: Colin Ian King <colin.king@...onical.com>

[ Upstream commit 1bbbab097a05276e312dd2462791d32b21ceb1ee ]

Currently the retry counter is not being decremented, leading to a
potential infinite spin if the scalar_reads don't change state.

Addresses-Coverity: ("Infinite loop")
Fixes: 280e54c9f614 ("drm/exynos: scaler: Reset hardware before starting the operation")
Signed-off-by: Colin Ian King <colin.king@...onical.com>
Signed-off-by: Inki Dae <inki.dae@...sung.com>
Signed-off-by: Sasha Levin <sashal@...nel.org>
---
 drivers/gpu/drm/exynos/exynos_drm_scaler.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/exynos/exynos_drm_scaler.c b/drivers/gpu/drm/exynos/exynos_drm_scaler.c
index ec9c1b7d31033..8989f8af716b7 100644
--- a/drivers/gpu/drm/exynos/exynos_drm_scaler.c
+++ b/drivers/gpu/drm/exynos/exynos_drm_scaler.c
@@ -94,12 +94,12 @@ static inline int scaler_reset(struct scaler_context *scaler)
 	scaler_write(SCALER_CFG_SOFT_RESET, SCALER_CFG);
 	do {
 		cpu_relax();
-	} while (retry > 1 &&
+	} while (--retry > 1 &&
 		 scaler_read(SCALER_CFG) & SCALER_CFG_SOFT_RESET);
 	do {
 		cpu_relax();
 		scaler_write(1, SCALER_INT_EN);
-	} while (retry > 0 && scaler_read(SCALER_INT_EN) != 1);
+	} while (--retry > 0 && scaler_read(SCALER_INT_EN) != 1);
 
 	return retry ? 0 : -EIO;
 }
-- 
2.20.1