linux-kernel - [PATCH] [v2] dmaengine: tegra20: Fix runtime PM imbalance on error

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Message-Id: <20210409082805.23643-1-dinghao.liu@zju.edu.cn>
Date:   Fri,  9 Apr 2021 16:28:05 +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>,
        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] [v2] dmaengine: tegra20: Fix runtime PM imbalance on error

pm_runtime_get_sync() will increase the runtime PM counter
even 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.

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

Changelog:

v2: - Fix another similar case in tegra_dma_synchronize().
---
 drivers/dma/tegra20-apb-dma.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/dma/tegra20-apb-dma.c b/drivers/dma/tegra20-apb-dma.c
index 71827d9b0aa1..b7260749e8ee 100644
--- a/drivers/dma/tegra20-apb-dma.c
+++ b/drivers/dma/tegra20-apb-dma.c
@@ -723,7 +723,7 @@ static void tegra_dma_issue_pending(struct dma_chan *dc)
 		goto end;
 	}
 	if (!tdc->busy) {
-		err = pm_runtime_get_sync(tdc->tdma->dev);
+		err = pm_runtime_resume_and_get(tdc->tdma->dev);
 		if (err < 0) {
 			dev_err(tdc2dev(tdc), "Failed to enable DMA\n");
 			goto end;
@@ -818,7 +818,7 @@ static void tegra_dma_synchronize(struct dma_chan *dc)
 	struct tegra_dma_channel *tdc = to_tegra_dma_chan(dc);
 	int err;
 
-	err = pm_runtime_get_sync(tdc->tdma->dev);
+	err = pm_runtime_resume_and_get(tdc->tdma->dev);
 	if (err < 0) {
 		dev_err(tdc2dev(tdc), "Failed to synchronize DMA: %d\n", err);
 		return;
-- 
2.17.1