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From:   Aditya Pakki <pakki001@umn.edu>
To:     pakki001@umn.edu
Cc:     kjlu@umn.edu, wu000273@umn.edu,
        Andrzej Hajda <a.hajda@samsung.com>,
        Neil Armstrong <narmstrong@baylibre.com>,
        Laurent Pinchart <Laurent.pinchart@ideasonboard.com>,
        Jonas Karlman <jonas@kwiboo.se>,
        Jernej Skrabec <jernej.skrabec@siol.net>,
        David Airlie <airlied@linux.ie>,
        Daniel Vetter <daniel@ffwll.ch>,
        dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org
Subject: [PATCH] drm/bridge: fix reference count leaks due to pm_runtime_get_sync()
Date:   Sat, 13 Jun 2020 21:40:05 -0500
Message-Id: <20200614024005.125578-1-pakki001@umn.edu>
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

On calling pm_runtime_get_sync() the reference count of the device
is incremented. In case of failure, decrement the
reference count before returning the error.

Signed-off-by: Aditya Pakki <pakki001@umn.edu>
---
 drivers/gpu/drm/bridge/cdns-dsi.c | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/bridge/cdns-dsi.c b/drivers/gpu/drm/bridge/cdns-dsi.c
index 69c3892caee5..583cb8547106 100644
--- a/drivers/gpu/drm/bridge/cdns-dsi.c
+++ b/drivers/gpu/drm/bridge/cdns-dsi.c
@@ -788,8 +788,10 @@ static void cdns_dsi_bridge_enable(struct drm_bridge *bridge)
 	u32 tmp, reg_wakeup, div;
 	int nlanes;
 
-	if (WARN_ON(pm_runtime_get_sync(dsi->base.dev) < 0))
+	if (WARN_ON(pm_runtime_get_sync(dsi->base.dev) < 0)) {
+		pm_runtime_put(dsi->base.dev);
 		return;
+	}
 
 	mode = &bridge->encoder->crtc->state->adjusted_mode;
 	nlanes = output->dev->lanes;
@@ -1028,8 +1030,10 @@ static ssize_t cdns_dsi_transfer(struct mipi_dsi_host *host,
 	int ret, i, tx_len, rx_len;
 
 	ret = pm_runtime_get_sync(host->dev);
-	if (ret < 0)
+	if (ret < 0) {
+		pm_runtime_put(host->dev);
 		return ret;
+	}
 
 	cdns_dsi_init_link(dsi);
 
-- 
2.25.1