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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, Zhang Qilong <zhangqilong3@huawei.com>,
        Vinod Koul <vkoul@kernel.org>, Sasha Levin <sashal@kernel.org>
Subject: [PATCH 5.10 14/86] dmaengine: mediatek:Fix PM usage reference leak of mtk_uart_apdma_alloc_chan_resources
Date:   Tue, 26 Apr 2022 10:20:42 +0200
Message-Id: <20220426081741.617352615@linuxfoundation.org>
In-Reply-To: <20220426081741.202366502@linuxfoundation.org>
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From: zhangqilong <zhangqilong3@huawei.com>

[ Upstream commit 545b2baac89b859180e51215468c05d85ea8465a ]

pm_runtime_get_sync will increment pm usage counter even it failed.
Forgetting to putting operation will result in reference leak here.
We fix it:
1) Replacing it with pm_runtime_resume_and_get to keep usage counter
   balanced.
2) Add putting operation before returning error.

Fixes:9135408c3ace4 ("dmaengine: mediatek: Add MediaTek UART APDMA support")
Signed-off-by: Zhang Qilong <zhangqilong3@huawei.com>
Link: https://lore.kernel.org/r/20220319022142.142709-1-zhangqilong3@huawei.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/dma/mediatek/mtk-uart-apdma.c | 9 ++++++---
 1 file changed, 6 insertions(+), 3 deletions(-)

diff --git a/drivers/dma/mediatek/mtk-uart-apdma.c b/drivers/dma/mediatek/mtk-uart-apdma.c
index 375e7e647df6..a1517ef1f4a0 100644
--- a/drivers/dma/mediatek/mtk-uart-apdma.c
+++ b/drivers/dma/mediatek/mtk-uart-apdma.c
@@ -274,7 +274,7 @@ static int mtk_uart_apdma_alloc_chan_resources(struct dma_chan *chan)
 	unsigned int status;
 	int ret;
 
-	ret = pm_runtime_get_sync(mtkd->ddev.dev);
+	ret = pm_runtime_resume_and_get(mtkd->ddev.dev);
 	if (ret < 0) {
 		pm_runtime_put_noidle(chan->device->dev);
 		return ret;
@@ -288,18 +288,21 @@ static int mtk_uart_apdma_alloc_chan_resources(struct dma_chan *chan)
 	ret = readx_poll_timeout(readl, c->base + VFF_EN,
 			  status, !status, 10, 100);
 	if (ret)
-		return ret;
+		goto err_pm;
 
 	ret = request_irq(c->irq, mtk_uart_apdma_irq_handler,
 			  IRQF_TRIGGER_NONE, KBUILD_MODNAME, chan);
 	if (ret < 0) {
 		dev_err(chan->device->dev, "Can't request dma IRQ\n");
-		return -EINVAL;
+		ret = -EINVAL;
+		goto err_pm;
 	}
 
 	if (mtkd->support_33bits)
 		mtk_uart_apdma_write(c, VFF_4G_SUPPORT, VFF_4G_SUPPORT_CLR_B);
 
+err_pm:
+	pm_runtime_put_noidle(mtkd->ddev.dev);
 	return ret;
 }
 
-- 
2.35.1