linux-kernel - [PATCH v1 1/2] dmaengine: tegra-apb: Don't save/restore IRQ flags in interrupt handler

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Message-Id: <20200319205228.8883-1-digetx@gmail.com>
Date:   Thu, 19 Mar 2020 23:52:27 +0300
From:   Dmitry Osipenko <digetx@...il.com>
To:     Thierry Reding <thierry.reding@...il.com>,
        Jonathan Hunter <jonathanh@...dia.com>,
        Laxman Dewangan <ldewangan@...dia.com>,
        Vinod Koul <vkoul@...nel.org>,
        Dan Williams <dan.j.williams@...el.com>
Cc:     Wolfram Sang <wsa@...-dreams.de>, linux-i2c@...r.kernel.org,
        linux-tegra@...r.kernel.org, dmaengine@...r.kernel.org,
        linux-kernel@...r.kernel.org
Subject: [PATCH v1 1/2] dmaengine: tegra-apb: Don't save/restore IRQ flags in interrupt handler

The interrupt is already disabled while interrupt handler is running, and
thus, there is no need to save/restore the IRQ flags within the spinlock.

Signed-off-by: Dmitry Osipenko <digetx@...il.com>
---
 drivers/dma/tegra20-apb-dma.c | 7 +++----
 1 file changed, 3 insertions(+), 4 deletions(-)

diff --git a/drivers/dma/tegra20-apb-dma.c b/drivers/dma/tegra20-apb-dma.c
index 4e295d121be6..26f427e02369 100644
--- a/drivers/dma/tegra20-apb-dma.c
+++ b/drivers/dma/tegra20-apb-dma.c
@@ -672,10 +672,9 @@ static void tegra_dma_tasklet(unsigned long data)
 static irqreturn_t tegra_dma_isr(int irq, void *dev_id)
 {
 	struct tegra_dma_channel *tdc = dev_id;
-	unsigned long flags;
 	u32 status;
 
-	spin_lock_irqsave(&tdc->lock, flags);
+	spin_lock(&tdc->lock);
 
 	trace_tegra_dma_isr(&tdc->dma_chan, irq);
 	status = tdc_read(tdc, TEGRA_APBDMA_CHAN_STATUS);
@@ -683,11 +682,11 @@ static irqreturn_t tegra_dma_isr(int irq, void *dev_id)
 		tdc_write(tdc, TEGRA_APBDMA_CHAN_STATUS, status);
 		tdc->isr_handler(tdc, false);
 		tasklet_schedule(&tdc->tasklet);
-		spin_unlock_irqrestore(&tdc->lock, flags);
+		spin_unlock(&tdc->lock);
 		return IRQ_HANDLED;
 	}
 
-	spin_unlock_irqrestore(&tdc->lock, flags);
+	spin_unlock(&tdc->lock);
 	dev_info(tdc2dev(tdc), "Interrupt already served status 0x%08x\n",
 		 status);
 
-- 
2.25.1