linux-kernel - [PATCH V2 resend 2/7] dmaengine/dw_dmac: Enable resubmission from callback routine.

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Date:	Tue, 26 Apr 2011 11:08:10 +0530
From:	Viresh Kumar <viresh.kumar@...com>
To:	<vinod.koul@...el.com>, <dan.j.williams@...el.com>
Cc:	<linux-kernel@...r.kernel.org>, <armando.visconti@...com>,
	<shiraz.hashim@...com>, Viresh Kumar <viresh.kumar@...com>
Subject: [PATCH V2 resend 2/7] dmaengine/dw_dmac: Enable resubmission from callback routine.

Resubmission of new transfer must be allowed from callbacks. For this release
lock before calling callback routine and enable them again.

Signed-off-by: Viresh Kumar <viresh.kumar@...com>
---
 drivers/dma/dw_dmac.c |   10 ++++------
 1 files changed, 4 insertions(+), 6 deletions(-)

diff --git a/drivers/dma/dw_dmac.c b/drivers/dma/dw_dmac.c
index 4f4df9f..dbe8203 100644
--- a/drivers/dma/dw_dmac.c
+++ b/drivers/dma/dw_dmac.c
@@ -197,8 +197,8 @@ static void dwc_dostart(struct dw_dma_chan *dwc, struct dw_desc *first)
 static void
 dwc_descriptor_complete(struct dw_dma_chan *dwc, struct dw_desc *desc)
 {
-	dma_async_tx_callback		callback;
-	void				*param;
+	dma_async_tx_callback		callback = NULL;
+	void				*param = NULL;
 	struct dma_async_tx_descriptor	*txd = &desc->txd;
 	struct dw_desc			*child;
 
@@ -238,12 +238,10 @@ dwc_descriptor_complete(struct dw_dma_chan *dwc, struct dw_desc *desc)
 		}
 	}
 
-	/*
-	 * The API requires that no submissions are done from a
-	 * callback, so we don't need to drop the lock here
-	 */
+	spin_unlock_irqrestore(&dwc->lock, dw->flags);
 	if (callback)
 		callback(param);
+	spin_lock_irqsave(&dwc->lock, dw->flags);
 }
 
 static void dwc_complete_all(struct dw_dma *dw, struct dw_dma_chan *dwc)
-- 
1.7.2.2

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