[PATCH 2/6] dmaengine: zynqmp_dma: Fix chan probe error handling

[Golla Nagendra]

Keep the real platform_get_irq() error value by returning ret directly,
initialize chan->irq to -1, and only assign chan->irq after
devm_request_irq() succeeds. In remove, free IRQ only for valid numbers
and delete device_node only when linked.

Move channel list registration to after successful IRQ registration,
initialize device_node list head during probe setup, and kill the
tasklet in the outer probe failure path when channel probe fails.

Fixes: b0cc417c1637 ("dmaengine: Add Xilinx zynqmp dma engine driver support")
Signed-off-by: Golla Nagendra <nagendra.golla@xxxxxxx>
---
 drivers/dma/xilinx/zynqmp_dma.c | 28 ++++++++++++++++++----------
 1 file changed, 18 insertions(+), 10 deletions(-)

diff --git a/drivers/dma/xilinx/zynqmp_dma.c b/drivers/dma/xilinx/zynqmp_dma.c
index b7c561280694..f7e4a177bd17 100644
--- a/drivers/dma/xilinx/zynqmp_dma.c
+++ b/drivers/dma/xilinx/zynqmp_dma.c
@@ -205,7 +205,7 @@ struct zynqmp_dma_desc_sw {
  * @desc_pool_p: Physical allocated descriptor base
  * @desc_free_cnt: Descriptor available count
  * @dev: The dma device
- * @irq: Channel IRQ
+ * @irq: Linux IRQ number, or -1 when not registered
  * @is_dmacoherent: Tells whether dma operations are coherent or not
  * @tasklet: Cleanup work after irq
  * @idle : Channel status;
@@ -896,10 +896,11 @@ static void zynqmp_dma_chan_remove(struct zynqmp_dma_chan *chan)
 	if (!chan)
 		return;
 
-	if (chan->irq)
+	if (chan->irq >= 0)
 		devm_free_irq(chan->zdev->dev, chan->irq, chan);
 	tasklet_kill(&chan->tasklet);
-	list_del(&chan->common.device_node);
+	if (!list_empty(&chan->common.device_node))
+		list_del(&chan->common.device_node);
 }
 
 /**
@@ -915,13 +916,14 @@ static int zynqmp_dma_chan_probe(struct zynqmp_dma_device *zdev,
 	struct zynqmp_dma_chan *chan;
 	struct device_node *node = pdev->dev.of_node;
 	const struct zynqmp_dma_config *match_data;
-	int err;
+	int err, ret;
 
 	chan = devm_kzalloc(zdev->dev, sizeof(*chan), GFP_KERNEL);
 	if (!chan)
 		return -ENOMEM;
 	chan->dev = zdev->dev;
 	chan->zdev = zdev;
+	chan->irq = -1;
 
 	chan->regs = devm_platform_ioremap_resource(pdev, 0);
 	if (IS_ERR(chan->regs))
@@ -954,22 +956,26 @@ static int zynqmp_dma_chan_probe(struct zynqmp_dma_device *zdev,
 	INIT_LIST_HEAD(&chan->pending_list);
 	INIT_LIST_HEAD(&chan->done_list);
 	INIT_LIST_HEAD(&chan->free_list);
+	INIT_LIST_HEAD(&chan->common.device_node);
 
 	dma_cookie_init(&chan->common);
 	chan->common.device = &zdev->common;
-	list_add_tail(&chan->common.device_node, &zdev->common.channels);
-
 	zynqmp_dma_init(chan);
-	chan->irq = platform_get_irq(pdev, 0);
-	if (chan->irq < 0)
-		return -ENXIO;
-	err = devm_request_irq(&pdev->dev, chan->irq, zynqmp_dma_irq_handler, 0,
+	ret = platform_get_irq(pdev, 0);
+	if (ret < 0)
+		return ret;
+
+	err = devm_request_irq(&pdev->dev, ret, zynqmp_dma_irq_handler, 0,
 			       "zynqmp-dma", chan);
 	if (err)
 		return err;
 
+	chan->irq = ret;
+
 	chan->desc_size = sizeof(struct zynqmp_dma_desc_ll);
 	chan->idle = true;
+	list_add_tail(&chan->common.device_node, &zdev->common.channels);
+
 	return 0;
 }
 
@@ -1134,6 +1140,8 @@ static int zynqmp_dma_probe(struct platform_device *pdev)
 	ret = zynqmp_dma_chan_probe(zdev, pdev);
 	if (ret) {
 		dev_err_probe(&pdev->dev, ret, "Probing channel failed\n");
+		if (zdev->chan)
+			tasklet_kill(&zdev->chan->tasklet);
 		goto err_disable_pm;
 	}
 
-- 
2.43.7