[PATCH v2 63/64] dmaengine: qcom-gpi: defer callbacks via vchan

[Allen Pais]

Complete descriptors through virt-dma instead of invoking callbacks
directly from event processing. This preserves the transfer result for
the shared vchan BH, which invokes the callback and frees the descriptor;
drain that BH before releasing channel resources.

Signed-off-by: Allen Pais <allen.lkml@xxxxxxxxx>
---
 drivers/dma/qcom/gpi.c | 17 +++++++++++++----
 1 file changed, 13 insertions(+), 4 deletions(-)

diff --git a/drivers/dma/qcom/gpi.c b/drivers/dma/qcom/gpi.c
index a5055a6273af..4cf68cf8eb2e 100644
--- a/drivers/dma/qcom/gpi.c
+++ b/drivers/dma/qcom/gpi.c
@@ -981,8 +981,12 @@ static void gpi_process_imed_data_event(struct gchan *gchan,
 		result.result = DMA_TRANS_NOERROR;
 	result.residue = gpi_desc->len - imed_event->length;
 
-	dma_cookie_complete(&vd->tx);
-	dmaengine_desc_get_callback_invoke(&vd->tx, &result);
+	spin_lock_irqsave(&gchan->vc.lock, flags);
+	list_del(&vd->node);
+	vd->tx_result = result;
+	vchan_cookie_complete(vd);
+	spin_unlock_irqrestore(&gchan->vc.lock, flags);
+	return;
 
 gpi_free_desc:
 	spin_lock_irqsave(&gchan->vc.lock, flags);
@@ -1060,8 +1064,12 @@ static void gpi_process_xfer_compl_event(struct gchan *gchan,
 	result.residue = gpi_desc->len - compl_event->length;
 	dev_dbg(gpii->gpi_dev->dev, "Residue %d\n", result.residue);
 
-	dma_cookie_complete(&vd->tx);
-	dmaengine_desc_get_callback_invoke(&vd->tx, &result);
+	spin_lock_irqsave(&gchan->vc.lock, flags);
+	list_del(&vd->node);
+	vd->tx_result = result;
+	vchan_cookie_complete(vd);
+	spin_unlock_irqrestore(&gchan->vc.lock, flags);
+	return;
 
 gpi_free_desc:
 	spin_lock_irqsave(&gchan->vc.lock, flags);
@@ -2009,6 +2017,7 @@ static void gpi_free_chan_resources(struct dma_chan *chan)
 
 	/* free all allocated memory */
 	gpi_free_ring(&gchan->ch_ring, gpii);
+	dma_chan_kill_bh(&gchan->vc.chan);
 	vchan_free_chan_resources(&gchan->vc);
 	kfree(gchan->config);
 
-- 
2.43.0