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From:   Qinglang Miao <miaoqinglang@huawei.com>
To:     Laxman Dewangan <ldewangan@nvidia.com>,
        Jon Hunter <jonathanh@nvidia.com>,
        Vinod Koul <vkoul@kernel.org>,
        Dan Williams <dan.j.williams@intel.com>,
        Thierry Reding <thierry.reding@gmail.com>
CC:     <dmaengine@vger.kernel.org>, <linux-tegra@vger.kernel.org>,
        <linux-kernel@vger.kernel.org>,
        Qinglang Miao <miaoqinglang@huawei.com>
Subject: [PATCH] dmaengine: tegra-apb: fix reference leak in tegra_dma_issue_pending and tegra_dma_synchronize
Date:   Fri, 27 Nov 2020 17:44:31 +0800
Message-ID: <20201127094431.120771-1-miaoqinglang@huawei.com>
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Precedence: bulk

pm_runtime_get_sync will increment pm usage counter even it
failed. Forgetting to putting operation will result in a
reference leak here.

A new function pm_runtime_resume_and_get is introduced in
[0] to keep usage counter balanced. So We fix the reference
leak by replacing it with new funtion.

[0] dd8088d5a896 ("PM: runtime: Add  pm_runtime_resume_and_get to deal with usage counter")

Fixes: 84a3f375eea9 ("dmaengine: tegra-apb: Keep clock enabled only during of DMA transfer")
Fixes: 664475cffb8c ("dmaengine: tegra-apb: Ensure that clock is enabled during of DMA synchronization")
Reported-by: Hulk Robot <hulkci@huawei.com>
Signed-off-by: Qinglang Miao <miaoqinglang@huawei.com>
---
 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 71827d9b0..b7260749e 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;
-- 
2.23.0