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Groups > linux.kernel > #1202546

[PATCH] dmaengine: fix balance of privatecnt inc/dec operations

From Robert Baldyga <r.baldyga@samsung.com>
Newsgroups linux.kernel
Subject [PATCH] dmaengine: fix balance of privatecnt inc/dec operations
Date 2015-08-07 12:30 +0200
Message-ID <pUN4u-557-13@gated-at.bofh.it> (permalink)
Organization linux.* mail to news gateway

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This patch increments privatecnt value and set DMA_PRIVATE in device
caps in dma_request_slave_channel() function. This is needed to keep
privatecnt increment/decrement balance.

As function dma_release_channel() decrements privatecnt counter, we need
to increment it when channel is requested. Otherwise privatecnt drops
into negatives after few dma_release_channel() calls.

Reported-by: Krzysztof Kozlowski <k.kozlowski@samsung.com>
Signed-off-by: Robert Baldyga <r.baldyga@samsung.com>
---
 drivers/dma/dmaengine.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/drivers/dma/dmaengine.c b/drivers/dma/dmaengine.c
index 4a4cce1..3ff284c 100644
--- a/drivers/dma/dmaengine.c
+++ b/drivers/dma/dmaengine.c
@@ -689,6 +689,10 @@ struct dma_chan *dma_request_slave_channel(struct device *dev,
 	struct dma_chan *ch = dma_request_slave_channel_reason(dev, name);
 	if (IS_ERR(ch))
 		return NULL;
+
+	dma_cap_set(DMA_PRIVATE, ch->device->cap_mask);
+	ch->device->privatecnt++;
+
 	return ch;
 }
 EXPORT_SYMBOL_GPL(dma_request_slave_channel);
-- 
1.9.1

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Thread

[PATCH] dmaengine: fix balance of privatecnt inc/dec operations Robert Baldyga <r.baldyga@samsung.com> - 2015-08-07 12:30 +0200
  Re: [PATCH] dmaengine: fix balance of privatecnt inc/dec operations Krzysztof Kozlowski <k.kozlowski@samsung.com> - 2015-08-10 02:20 +0200
  Re: [PATCH] dmaengine: fix balance of privatecnt inc/dec operations Vinod Koul <vinod.koul@intel.com> - 2015-08-17 19:20 +0200

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