[PATCH 5/7] dmaengine: mv_xor: drain IRQ tasklet before freeing channel memory

[Jiale Yao <yaojiale02@163.com>]

The XOR interrupt handler schedules irq_tasklet to clean channel
descriptor lists. Both device removal and late channel setup failures
can free the coherent descriptor pool while a previously queued tasklet
still refers to it.

Release the IRQ first so no new tasklet can be queued, kill the tasklet,
and only then free the descriptor pool and DMA mappings.

Fixes: ff7b04796d98 ("dmaengine: DMA engine driver for Marvell XOR engine")
Signed-off-by: Jiale Yao <yaojiale02@163.com>
---
 drivers/dma/mv_xor.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/drivers/dma/mv_xor.c b/drivers/dma/mv_xor.c
index 25ed61f1b089..ec746cd16960 100644
--- a/drivers/dma/mv_xor.c
+++ b/drivers/dma/mv_xor.c
@@ -1013,6 +1013,9 @@ static int mv_xor_channel_remove(struct mv_xor_chan *mv_chan)
 
 	dma_async_device_unregister(&mv_chan->dmadev);
 
+	free_irq(mv_chan->irq, mv_chan);
+	tasklet_kill(&mv_chan->irq_tasklet);
+
 	dma_free_wc(dev, MV_XOR_POOL_SIZE,
 			  mv_chan->dma_desc_pool_virt, mv_chan->dma_desc_pool);
 	dma_unmap_single(dev, mv_chan->dummy_src_addr,
@@ -1025,8 +1028,6 @@ static int mv_xor_channel_remove(struct mv_xor_chan *mv_chan)
 		list_del(&chan->device_node);
 	}
 
-	free_irq(mv_chan->irq, mv_chan);
-
 	return 0;
 }
 
@@ -1162,6 +1163,7 @@ mv_xor_channel_add(struct mv_xor_device *xordev,
 
 err_free_irq:
 	free_irq(mv_chan->irq, mv_chan);
+	tasklet_kill(&mv_chan->irq_tasklet);
 err_free_dma:
 	dma_free_wc(&pdev->dev, MV_XOR_POOL_SIZE,
 			  mv_chan->dma_desc_pool_virt, mv_chan->dma_desc_pool);
-- 
2.34.1