[PATCH 1/6] dmaengine: zynqmp_dma: Fix alloc_chan_resources error cleanup

[Golla Nagendra]

Channel resource allocation can fail after runtime PM has been acquired
and after part of the descriptor state has been initialized. Without
proper rollback, the error path leaks a runtime PM reference and, on
coherent allocation failure, also leaks the software descriptor pool.

Fix this by balancing runtime PM usage before returning an error and
releasing any partially allocated software descriptor pool.

Fixes: 8982d48af36d ("dmaengine: zynqmp_dma: Fix PM reference leak in zynqmp_dma_alloc_chan_resourc()")
Signed-off-by: Golla Nagendra <nagendra.golla@xxxxxxx>
---
 drivers/dma/xilinx/zynqmp_dma.c | 19 +++++++++++++++----
 1 file changed, 15 insertions(+), 4 deletions(-)

diff --git a/drivers/dma/xilinx/zynqmp_dma.c b/drivers/dma/xilinx/zynqmp_dma.c
index f6a812e49ddc..b7c561280694 100644
--- a/drivers/dma/xilinx/zynqmp_dma.c
+++ b/drivers/dma/xilinx/zynqmp_dma.c
@@ -483,8 +483,10 @@ static int zynqmp_dma_alloc_chan_resources(struct dma_chan *dchan)
 		return ret;
 
 	chan->sw_desc_pool = kzalloc_objs(*desc, ZYNQMP_DMA_NUM_DESCS);
-	if (!chan->sw_desc_pool)
-		return -ENOMEM;
+	if (!chan->sw_desc_pool) {
+		ret = -ENOMEM;
+		goto err_pm;
+	}
 
 	chan->idle = true;
 	chan->desc_free_cnt = ZYNQMP_DMA_NUM_DESCS;
@@ -502,8 +504,10 @@ static int zynqmp_dma_alloc_chan_resources(struct dma_chan *dchan)
 					       (2 * ZYNQMP_DMA_DESC_SIZE(chan) *
 					       ZYNQMP_DMA_NUM_DESCS),
 					       &chan->desc_pool_p, GFP_KERNEL);
-	if (!chan->desc_pool_v)
-		return -ENOMEM;
+	if (!chan->desc_pool_v) {
+		ret = -ENOMEM;
+		goto err_free_sw_desc_pool;
+	}
 
 	for (i = 0; i < ZYNQMP_DMA_NUM_DESCS; i++) {
 		desc = chan->sw_desc_pool + i;
@@ -516,6 +520,13 @@ static int zynqmp_dma_alloc_chan_resources(struct dma_chan *dchan)
 	}
 
 	return ZYNQMP_DMA_NUM_DESCS;
+
+err_free_sw_desc_pool:
+	kfree(chan->sw_desc_pool);
+	chan->sw_desc_pool = NULL;
+err_pm:
+	pm_runtime_put_autosuspend(chan->dev);
+	return ret;
 }
 
 /**
-- 
2.43.7