When fsldma_request_irqs() fails on a per-channel IRQ, the unwind
loop starts at the current index i, which calls free_irq() on the
IRQ that request_irq() just failed to register.  Decrement i before
the loop to skip the failed channel.

Bug introduced by commit 586f54672b33 ("dmaengine: fsldma: convert
to platform_get_irq_optional()").

Assisted-by: opencode:big-pickle
Signed-off-by: Rosen Penev <redacted>
---
 drivers/dma/fsldma.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/dma/fsldma.c b/drivers/dma/fsldma.c
index 4475d50a94f5..c04a7fbd2ed0 100644
--- a/drivers/dma/fsldma.c
+++ b/drivers/dma/fsldma.c

@@ -1088,7 +1088,7 @@ static int fsldma_request_irqs(struct fsldma_device *fdev)
 	return 0;
 
 out_unwind:
-	for (/* none */; i >= 0; i--) {
+	for (i--; i >= 0; i--) {
 		chan = fdev->chan[i];
 		if (!chan)
 			continue;

-- 
2.54.0