linux-kernel - [PATCH] dma: Revert "dmaengine: mic_x100: add missing spin

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Date:	Tue, 22 Dec 2015 19:35:23 -0800
From:	Ashutosh Dixit <ashutosh.dixit@...el.com>
To:	Vinod Koul <vinod.koul@...el.com>, linux-kernel@...r.kernel.org,
	dmaengine@...r.kernel.org
Cc:	Ashutosh Dixit <ashutosh.dixit@...el.com>,
	Sudeep Dutt <sudeep.dutt@...el.com>,
	Nikhil Rao <nikhil.rao@...el.com>,
	Siva Yerramreddy <yshivakrishna@...il.com>,
	Saurabh Sengar <saurabh.truth@...il.com>
Subject: [PATCH] dma: Revert "dmaengine: mic_x100: add missing spin_unlock"

This reverts commit e958e079e254 ("dmaengine: mic_x100: add missing
spin_unlock").

The above patch is incorrect. There is nothing wrong with the original
code. The spin_lock is acquired in the "prep" functions and released
in "submit".

Signed-off-by: Ashutosh Dixit <ashutosh.dixit@...el.com>
---
 drivers/dma/mic_x100_dma.c | 15 +++++----------
 1 file changed, 5 insertions(+), 10 deletions(-)

diff --git a/drivers/dma/mic_x100_dma.c b/drivers/dma/mic_x100_dma.c
index cddfa8d..068e920 100644
--- a/drivers/dma/mic_x100_dma.c
+++ b/drivers/dma/mic_x100_dma.c
@@ -317,7 +317,6 @@ mic_dma_prep_memcpy_lock(struct dma_chan *ch, dma_addr_t dma_dest,
 	struct mic_dma_chan *mic_ch = to_mic_dma_chan(ch);
 	struct device *dev = mic_dma_ch_to_device(mic_ch);
 	int result;
-	struct dma_async_tx_descriptor *tx = NULL;
 
 	if (!len && !flags)
 		return NULL;
@@ -325,13 +324,10 @@ mic_dma_prep_memcpy_lock(struct dma_chan *ch, dma_addr_t dma_dest,
 	spin_lock(&mic_ch->prep_lock);
 	result = mic_dma_do_dma(mic_ch, flags, dma_src, dma_dest, len);
 	if (result >= 0)
-		tx = allocate_tx(mic_ch);
-
-	if (!tx)
-		dev_err(dev, "Error enqueueing dma, error=%d\n", result);
-
+		return allocate_tx(mic_ch);
+	dev_err(dev, "Error enqueueing dma, error=%d\n", result);
 	spin_unlock(&mic_ch->prep_lock);
-	return tx;
+	return NULL;
 }
 
 static struct dma_async_tx_descriptor *
@@ -339,14 +335,13 @@ mic_dma_prep_interrupt_lock(struct dma_chan *ch, unsigned long flags)
 {
 	struct mic_dma_chan *mic_ch = to_mic_dma_chan(ch);
 	int ret;
-	struct dma_async_tx_descriptor *tx = NULL;
 
 	spin_lock(&mic_ch->prep_lock);
 	ret = mic_dma_do_dma(mic_ch, flags, 0, 0, 0);
 	if (!ret)
-		tx = allocate_tx(mic_ch);
+		return allocate_tx(mic_ch);
 	spin_unlock(&mic_ch->prep_lock);
-	return tx;
+	return NULL;
 }
 
 /* Return the status of the transaction */
-- 
2.0.0.rc3.2.g998f840

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