linux-kernel - [PATCH AUTOSEL 5.16 023/109] drm/bridge: Add missing pm_runtime_put

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Date:   Fri,  1 Apr 2022 10:31:30 -0400
From:   Sasha Levin <sashal@...nel.org>
To:     linux-kernel@...r.kernel.org, stable@...r.kernel.org
Cc:     Yongzhi Liu <lyz_cs@....edu.cn>,
        Laurent Pinchart <laurent.pinchart@...asonboard.com>,
        Robert Foss <robert.foss@...aro.org>,
        Sasha Levin <sashal@...nel.org>, andrzej.hajda@...el.com,
        narmstrong@...libre.com, airlied@...ux.ie, daniel@...ll.ch,
        dri-devel@...ts.freedesktop.org
Subject: [PATCH AUTOSEL 5.16 023/109] drm/bridge: Add missing pm_runtime_put_sync

From: Yongzhi Liu <lyz_cs@....edu.cn>

[ Upstream commit 46f47807738441e354873546dde0b000106c068a ]

pm_runtime_get_sync() will increase the rumtime PM counter
even when it returns an error. Thus a pairing decrement is needed
to prevent refcount leak. Fix this by replacing this API with
pm_runtime_resume_and_get(), which will not change the runtime
PM counter on error. Besides, a matching decrement is needed
on the error handling path to keep the counter balanced.

Signed-off-by: Yongzhi Liu <lyz_cs@....edu.cn>
Reviewed-by: Laurent Pinchart <laurent.pinchart@...asonboard.com>
Signed-off-by: Robert Foss <robert.foss@...aro.org>
Link: https://patchwork.freedesktop.org/patch/msgid/1643008835-73961-1-git-send-email-lyz_cs@pku.edu.cn
Signed-off-by: Sasha Levin <sashal@...nel.org>
---
 drivers/gpu/drm/bridge/nwl-dsi.c | 18 ++++++++++++------
 1 file changed, 12 insertions(+), 6 deletions(-)

diff --git a/drivers/gpu/drm/bridge/nwl-dsi.c b/drivers/gpu/drm/bridge/nwl-dsi.c
index af07eeb47ca0..1529b9e3d576 100644
--- a/drivers/gpu/drm/bridge/nwl-dsi.c
+++ b/drivers/gpu/drm/bridge/nwl-dsi.c
@@ -861,18 +861,19 @@ nwl_dsi_bridge_mode_set(struct drm_bridge *bridge,
 	memcpy(&dsi->mode, adjusted_mode, sizeof(dsi->mode));
 	drm_mode_debug_printmodeline(adjusted_mode);
 
-	pm_runtime_get_sync(dev);
+	if (pm_runtime_resume_and_get(dev) < 0)
+		return;
 
 	if (clk_prepare_enable(dsi->lcdif_clk) < 0)
-		return;
+		goto runtime_put;
 	if (clk_prepare_enable(dsi->core_clk) < 0)
-		return;
+		goto runtime_put;
 
 	/* Step 1 from DSI reset-out instructions */
 	ret = reset_control_deassert(dsi->rst_pclk);
 	if (ret < 0) {
 		DRM_DEV_ERROR(dev, "Failed to deassert PCLK: %d\n", ret);
-		return;
+		goto runtime_put;
 	}
 
 	/* Step 2 from DSI reset-out instructions */
@@ -882,13 +883,18 @@ nwl_dsi_bridge_mode_set(struct drm_bridge *bridge,
 	ret = reset_control_deassert(dsi->rst_esc);
 	if (ret < 0) {
 		DRM_DEV_ERROR(dev, "Failed to deassert ESC: %d\n", ret);
-		return;
+		goto runtime_put;
 	}
 	ret = reset_control_deassert(dsi->rst_byte);
 	if (ret < 0) {
 		DRM_DEV_ERROR(dev, "Failed to deassert BYTE: %d\n", ret);
-		return;
+		goto runtime_put;
 	}
+
+	return;
+
+runtime_put:
+	pm_runtime_put_sync(dev);
 }
 
 static void
-- 
2.34.1