linux-kernel - [PATCH] dmaengine: stm32-mdma: call pm_runtime_put if pm_runtime_get

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Message-Id: <20200603182850.66692-1-navid.emamdoost@gmail.com>
Date:   Wed,  3 Jun 2020 13:28:50 -0500
From:   Navid Emamdoost <navid.emamdoost@...il.com>
To:     Vinod Koul <vkoul@...nel.org>,
        Dan Williams <dan.j.williams@...el.com>,
        Maxime Coquelin <mcoquelin.stm32@...il.com>,
        Alexandre Torgue <alexandre.torgue@...com>,
        dmaengine@...r.kernel.org,
        linux-stm32@...md-mailman.stormreply.com,
        linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org
Cc:     emamd001@....edu, wu000273@....edu, kjlu@....edu, smccaman@....edu,
        Navid Emamdoost <navid.emamdoost@...il.com>
Subject: [PATCH] dmaengine: stm32-mdma: call pm_runtime_put if pm_runtime_get_sync fails

Calling pm_runtime_get_sync increments the counter even in case of
failure, causing incorrect ref count. Call pm_runtime_put if
pm_runtime_get_sync fails.

Signed-off-by: Navid Emamdoost <navid.emamdoost@...il.com>
---
 drivers/dma/stm32-mdma.c | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/drivers/dma/stm32-mdma.c b/drivers/dma/stm32-mdma.c
index 5469563703d1..79bee1bb73f6 100644
--- a/drivers/dma/stm32-mdma.c
+++ b/drivers/dma/stm32-mdma.c
@@ -1449,8 +1449,10 @@ static int stm32_mdma_alloc_chan_resources(struct dma_chan *c)
 	}
 
 	ret = pm_runtime_get_sync(dmadev->ddev.dev);
-	if (ret < 0)
+	if (ret < 0) {
+		pm_runtime_put(dmadev->ddev.dev);
 		return ret;
+	}
 
 	ret = stm32_mdma_disable_chan(chan);
 	if (ret < 0)
@@ -1718,8 +1720,10 @@ static int stm32_mdma_pm_suspend(struct device *dev)
 	int ret;
 
 	ret = pm_runtime_get_sync(dev);
-	if (ret < 0)
+	if (ret < 0) {
+		pm_runtime_put_sync(dev);
 		return ret;
+	}
 
 	for (id = 0; id < dmadev->nr_channels; id++) {
 		ccr = stm32_mdma_read(dmadev, STM32_MDMA_CCR(id));
-- 
2.17.1