serial: sprd: Fix DMA buffer leak issue

[ Upstream commit cd119fd ]

Release DMA buffer when _probe() returns failure to avoid memory leak.

Fixes: f4487db ("serial: sprd: Add DMA mode support")
Signed-off-by: Chunyan Zhang <chunyan.zhang@unisoc.com>
Reviewed-by: Baolin Wang <baolin.wang@linux.alibaba.com>
Link: https://lore.kernel.org/r/20230725064053.235448-2-chunyan.zhang@unisoc.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>

drivers/tty/serial/sprd_serial.c

@@ -367,7 +367,7 @@ static void sprd_rx_free_buf(struct sprd_uart_port *sp)
 	if (sp->rx_dma.virt)
 		dma_free_coherent(sp->port.dev, SPRD_UART_RX_SIZE,
 				  sp->rx_dma.virt, sp->rx_dma.phys_addr);
-
+	sp->rx_dma.virt = NULL;
 }
 
 static int sprd_rx_dma_config(struct uart_port *port, u32 burst)
@@ -1229,7 +1229,7 @@ static int sprd_probe(struct platform_device *pdev)
 		ret = uart_register_driver(&sprd_uart_driver);
 		if (ret < 0) {
 			pr_err("Failed to register SPRD-UART driver\n");
-			return ret;
+			goto free_rx_buf;
 		}
 	}
 
@@ -1248,6 +1248,7 @@ static int sprd_probe(struct platform_device *pdev)
 	sprd_port[index] = NULL;
 	if (--sprd_ports_num == 0)
 		uart_unregister_driver(&sprd_uart_driver);
+free_rx_buf:
 	sprd_rx_free_buf(sport);
 	return ret;
 }