linux-kernel - [PATCH] spi: atmel: fixed spin_lock usage inside atmel_spi

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Date:   Fri, 15 Dec 2017 17:40:17 +0200
From:   Radu Pirea <radu.pirea@...rochip.com>
To:     <linux-spi@...r.kernel.org>, <broonie@...nel.org>,
        <nicolas.ferre@...rochip.com>,
        <alexandre.belloni@...e-electrons.com>,
        <Wenyou.Yang@...rochip.com>, <baijiaju1990@...il.com>
CC:     <linux-kernel@...r.kernel.org>,
        <linux-arm-kernel@...ts.infradead.org>,
        Radu Pirea <radu.pirea@...rochip.com>
Subject: [PATCH] spi: atmel: fixed spin_lock usage inside atmel_spi_remove

The only part of atmel_spi_remove which needs to be atomic is hardware
reset.

atmel_spi_stop_dma calls dma_terminate_all and this needs interrupts
enabled.
atmel_spi_release_dma calls dma_release_channel and dma_release_channel
locks a mutex inside of spin_lock.

So the call of these functions can't be inside a spin_lock.

Reported-by: Jia-Ju Bai <baijiaju1990@...il.com>
Signed-off-by: Radu Pirea <radu.pirea@...rochip.com>
---
 drivers/spi/spi-atmel.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/spi/spi-atmel.c b/drivers/spi/spi-atmel.c
index f95da36..6694709 100644
--- a/drivers/spi/spi-atmel.c
+++ b/drivers/spi/spi-atmel.c
@@ -1661,12 +1661,12 @@ static int atmel_spi_remove(struct platform_device *pdev)
 	pm_runtime_get_sync(&pdev->dev);
 
 	/* reset the hardware and block queue progress */
-	spin_lock_irq(&as->lock);
 	if (as->use_dma) {
 		atmel_spi_stop_dma(master);
 		atmel_spi_release_dma(master);
 	}
 
+	spin_lock_irq(&as->lock);
 	spi_writel(as, CR, SPI_BIT(SWRST));
 	spi_writel(as, CR, SPI_BIT(SWRST)); /* AT91SAM9263 Rev B workaround */
 	spi_readl(as, SR);
-- 
2.7.4