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

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>
Reviewed-by: Michael Moese <mmoese@suse.de>
Link: https://lore.kernel.org/r/20191013220016.9369-1-colin.king@canonical.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/tty/serial/8250/8250_men_mcb.c b/drivers/tty/serial/8250/8250_men_mcb.c
index 02c5aff58a7408d3509f020b18f5a5cd93eac6c6..8df89e9cd2542d05dff25fc377b08d30a9efe5c5 100644 (file)
--- 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)