[PATCH v2] serial: altera_jtaguart: handle uart_add_one_port() failures

[Myeonghun Pak <mhun512@gmail.com>]

altera_jtaguart_probe() maps the register window before registering the
UART port, but it ignores failures from uart_add_one_port(). If port
registration fails, probe still returns success and the mapping remains
live until a later remove path that is not part of probe failure cleanup.

Return the uart_add_one_port() error and unmap the register window on
that failure path.

This issue was identified during our ongoing static-analysis research while
reviewing kernel code.

Fixes: 5bcd601049c6 ("serial: Add driver for the Altera JTAG UART")
Co-developed-by: Ijae Kim <ae878000@gmail.com>
Signed-off-by: Ijae Kim <ae878000@gmail.com>
Signed-off-by: Myeonghun Pak <mhun512@gmail.com>
---
Changes in v2:
- Drop the unnecessary port->membase = NULL assignment.

 drivers/tty/serial/altera_jtaguart.c | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/drivers/tty/serial/altera_jtaguart.c b/drivers/tty/serial/altera_jtaguart.c
index d47a62d1c9..20f079fe11 100644
--- a/drivers/tty/serial/altera_jtaguart.c
+++ b/drivers/tty/serial/altera_jtaguart.c
@@ -379,6 +379,7 @@ static int altera_jtaguart_probe(struct platform_device *pdev)
 	struct resource *res_mem;
 	int i = pdev->id;
 	int irq;
+	int ret;
 
 	/* -1 emphasizes that the platform must have one port, no .N suffix */
 	if (i == -1)
@@ -418,7 +419,11 @@ static int altera_jtaguart_probe(struct platform_device *pdev)
 	port->flags = UPF_BOOT_AUTOCONF;
 	port->dev = &pdev->dev;
 
-	uart_add_one_port(&altera_jtaguart_driver, port);
+	ret = uart_add_one_port(&altera_jtaguart_driver, port);
+	if (ret) {
+		iounmap(port->membase);
+		return ret;
+	}
 
 	return 0;
 }
-- 
2.47.1