ARM: tegra: dma: Do not call complete callback on canceled requests

Calling the complete callback when a request is cancelled leads to
locking problems in the callback, which could be called from an IRQ
with no locks held, or from whatever context called
tegra_dma_dequeue_req.  Instead, expect the caller to handle the
now-cancelled request as needed.

Also removes tegra_dma_dequeue, since all users can be trivially
converted to tegra_dma_dequeue_req.

Change-Id: If699239c09c78d1cd3afa0eaad46535b1d401a24
Signed-off-by: Colin Cross <ccross@android.com>

1 files changed, 1 insertions, 21 deletions

diff --git a/arch/arm/mach-tegra/dma.c b/arch/arm/mach-tegra/dma.c
index 6020871f5ef6..cfe017d1c9cf 100644
--- a/arch/arm/mach-tegra/dma.c
+++ b/arch/arm/mach-tegra/dma.c
@@ -137,24 +137,6 @@ static void tegra_dma_update_hw_partial(struct tegra_dma_channel *ch,
 	struct tegra_dma_req *req);
 static void tegra_dma_stop(struct tegra_dma_channel *ch);
 
-void tegra_dma_flush(struct tegra_dma_channel *ch)
-{
-}
-EXPORT_SYMBOL(tegra_dma_flush);
-
-void tegra_dma_dequeue(struct tegra_dma_channel *ch)
-{
-	struct tegra_dma_req *req;
-
-	if (tegra_dma_is_empty(ch))
-		return;
-
-	req = list_entry(ch->list.next, typeof(*req), node);
-
-	tegra_dma_dequeue_req(ch, req);
-	return;
-}
-
 void tegra_dma_stop(struct tegra_dma_channel *ch)
 {
 	u32 csr;
@@ -250,7 +232,7 @@ int tegra_dma_dequeue_req(struct tegra_dma_channel *ch,
 	}
 	if (!found) {
 		spin_unlock_irqrestore(&ch->lock, irq_flags);
-		return 0;
+		return -EINVAL;
 	}
 
 	if (!stop)
@@ -286,8 +268,6 @@ skip_status:
 
 	spin_unlock_irqrestore(&ch->lock, irq_flags);
 
-	/* Callback should be called without any lock */
-	req->complete(req);
 	return 0;
 }
 EXPORT_SYMBOL(tegra_dma_dequeue_req);