[PATCH] 8250-men-mcb: fix error checking when get_num_ports returns -ENODEV

[PATCH] 8250-men-mcb: fix error checking when get_num_ports returns -ENODEV

[Colin King]

From: Colin Ian King <colin.king@canonical.com>

The current checking for failure on the number of ports fails when
-ENODEV is returned from the call to get_num_ports. Fix this by making
num_ports and loop counter i signed rather than unsigned ints. Also
add check for num_ports being less than zero to check for -ve error
returns.

Addresses-Coverity: ("Unsigned compared against 0")
Fixes: e2fea54e4592 ("8250-men-mcb: add support for 16z025 and 16z057")
Signed-off-by: Colin Ian King <colin.king@canonical.com>
---
 drivers/tty/serial/8250/8250_men_mcb.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/drivers/tty/serial/8250/8250_men_mcb.c b/drivers/tty/serial/8250/8250_men_mcb.c
index 02c5aff58a74..8df89e9cd254 100644
--- a/drivers/tty/serial/8250/8250_men_mcb.c
+++ b/drivers/tty/serial/8250/8250_men_mcb.c
@@ -72,8 +72,8 @@ static int serial_8250_men_mcb_probe(struct mcb_device *mdev,
 {
 	struct serial_8250_men_mcb_data *data;
 	struct resource *mem;
-	unsigned int num_ports;
-	unsigned int i;
+	int num_ports;
+	int i;
 	void __iomem *membase;
 
 	mem = mcb_get_resource(mdev, IORESOURCE_MEM);
@@ -88,7 +88,7 @@ static int serial_8250_men_mcb_probe(struct mcb_device *mdev,
 	dev_dbg(&mdev->dev, "found a 16z%03u with %u ports\n",
 		mdev->id, num_ports);
 
-	if (num_ports == 0 || num_ports > 4) {
+	if (num_ports <= 0 || num_ports > 4) {
 		dev_err(&mdev->dev, "unexpected number of ports: %u\n",
 			num_ports);
 		return -ENODEV;
@@ -133,7 +133,7 @@ static int serial_8250_men_mcb_probe(struct mcb_device *mdev,
 
 static void serial_8250_men_mcb_remove(struct mcb_device *mdev)
 {
-	unsigned int num_ports, i;
+	int num_ports, i;
 	struct serial_8250_men_mcb_data *data = mcb_get_drvdata(mdev);
 
 	if (!data)
-- 
2.20.1

Re: [PATCH] 8250-men-mcb: fix error checking when get_num_ports returns -ENODEV

[Michael Moese]

On 14.10.19 00:00, Colin King wrote:
> From: Colin Ian King <colin.king@canonical.com>
> 
> The current checking for failure on the number of ports fails when
> -ENODEV is returned from the call to get_num_ports. Fix this by making
> num_ports and loop counter i signed rather than unsigned ints. Also
> add check for num_ports being less than zero to check for -ve error
> returns.
> 
> Addresses-Coverity: ("Unsigned compared against 0")
> Fixes: e2fea54e4592 ("8250-men-mcb: add support for 16z025 and 16z057")
> Signed-off-by: Colin Ian King <colin.king@canonical.com>

This looks more than reasonable to me, thanks.

Reviewed-by: Michael Moese <mmoese@suse.de>

> ---
>   drivers/tty/serial/8250/8250_men_mcb.c | 8 ++++----
>   1 file changed, 4 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/tty/serial/8250/8250_men_mcb.c b/drivers/tty/serial/8250/8250_men_mcb.c
> index 02c5aff58a74..8df89e9cd254 100644
> --- a/drivers/tty/serial/8250/8250_men_mcb.c
> +++ b/drivers/tty/serial/8250/8250_men_mcb.c
> @@ -72,8 +72,8 @@ static int serial_8250_men_mcb_probe(struct mcb_device *mdev,
>   {
>   	struct serial_8250_men_mcb_data *data;
>   	struct resource *mem;
> -	unsigned int num_ports;
> -	unsigned int i;
> +	int num_ports;
> +	int i;
>   	void __iomem *membase;
>   
>   	mem = mcb_get_resource(mdev, IORESOURCE_MEM);
> @@ -88,7 +88,7 @@ static int serial_8250_men_mcb_probe(struct mcb_device *mdev,
>   	dev_dbg(&mdev->dev, "found a 16z%03u with %u ports\n",
>   		mdev->id, num_ports);
>   
> -	if (num_ports == 0 || num_ports > 4) {
> +	if (num_ports <= 0 || num_ports > 4) {
>   		dev_err(&mdev->dev, "unexpected number of ports: %u\n",
>   			num_ports);
>   		return -ENODEV;
> @@ -133,7 +133,7 @@ static int serial_8250_men_mcb_probe(struct mcb_device *mdev,
>   
>   static void serial_8250_men_mcb_remove(struct mcb_device *mdev)
>   {
> -	unsigned int num_ports, i;
> +	int num_ports, i;
>   	struct serial_8250_men_mcb_data *data = mcb_get_drvdata(mdev);
>   
>   	if (!data)
> 

-- 
Michael Moese <mmoese@suse.de>
QA Engineer
PGP Fingerprint: 4CCE 3896 F873 2CA5 2382  3C6F 6021 375C 8635 7E74

SUSE Software Solutions Germany GmbH
Maxfeldstr. 5
90409 Nürnberg
Germany

(HRB 247165, AG München)
Geschäftsführer: Felix Imendörffer