linux-kernel - [PATCH] [v5] dmaengine: tegra210-adma: Fix runtime PM imbalance on error

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Message-Id: <20200624064626.19855-1-dinghao.liu@zju.edu.cn>
Date:   Wed, 24 Jun 2020 14:46:26 +0800
From:   Dinghao Liu <dinghao.liu@....edu.cn>
To:     dinghao.liu@....edu.cn, kjlu@....edu
Cc:     Laxman Dewangan <ldewangan@...dia.com>,
        Jon Hunter <jonathanh@...dia.com>,
        Dan Williams <dan.j.williams@...el.com>,
        Vinod Koul <vkoul@...nel.org>,
        Thierry Reding <thierry.reding@...il.com>,
        dmaengine@...r.kernel.org, linux-tegra@...r.kernel.org,
        linux-kernel@...r.kernel.org
Subject: [PATCH] [v5] dmaengine: tegra210-adma: Fix runtime PM imbalance on error

pm_runtime_get_sync() increments the runtime PM usage counter even
when it returns an error code. Thus a pairing decrement is needed on
the error handling path to keep the counter balanced.

Signed-off-by: Dinghao Liu <dinghao.liu@....edu.cn>
---

Changelog:

v2: - Merge two patches that fix runtime PM imbalance in
      tegra_adma_probe() and tegra_adma_alloc_chan_resources()
      respectively.

v3: - Use pm_runtime_put_noidle() instead of pm_runtime_put_sync()
      in tegra_adma_alloc_chan_resources(). _noidle() is the simplest
      one and it is sufficient for fixing this bug.

v4: - Use pm_runtime_put_noidle() instead of pm_runtime_put_sync()
      in tegra_adma_probe(). _noidle() is the simplest one and it is
      sufficient for fixing this bug.

v5: - Refine commit message.
---
 drivers/dma/tegra210-adma.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/drivers/dma/tegra210-adma.c b/drivers/dma/tegra210-adma.c
index db58d7e4f9fe..c5fa2ef74abc 100644
--- a/drivers/dma/tegra210-adma.c
+++ b/drivers/dma/tegra210-adma.c
@@ -658,6 +658,7 @@ static int tegra_adma_alloc_chan_resources(struct dma_chan *dc)
 
 	ret = pm_runtime_get_sync(tdc2dev(tdc));
 	if (ret < 0) {
+		pm_runtime_put_noidle(tdc2dev(tdc));
 		free_irq(tdc->irq, tdc);
 		return ret;
 	}
@@ -869,8 +870,10 @@ static int tegra_adma_probe(struct platform_device *pdev)
 	pm_runtime_enable(&pdev->dev);
 
 	ret = pm_runtime_get_sync(&pdev->dev);
-	if (ret < 0)
+	if (ret < 0) {
+		pm_runtime_put_noidle(&pdev->dev);
 		goto rpm_disable;
+	}
 
 	ret = tegra_adma_init(tdma);
 	if (ret)
-- 
2.17.1