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Subject[PATCH v1 5/8] watchdog: f71808e_wdt: do stricter parameter validation
Date
We check the f71862fg_pin module parameter every time a watchdog device
for the f71862fg is opened, but the parameter can't change at runtime.

If we move the check to the start of init:

- We catch userspace passing invalid, but unused, values
- We check the condition only once
- We simplify the code

Do so.

Signed-off-by: Ahmad Fatoum <a.fatoum@pengutronix.de>
---
drivers/watchdog/f71808e_wdt.c | 37 +++++++++++-----------------------
1 file changed, 12 insertions(+), 25 deletions(-)

diff --git a/drivers/watchdog/f71808e_wdt.c b/drivers/watchdog/f71808e_wdt.c
index 26bf366aebc2..9f7823819ed1 100644
--- a/drivers/watchdog/f71808e_wdt.c
+++ b/drivers/watchdog/f71808e_wdt.c
@@ -306,27 +306,6 @@ static int watchdog_keepalive(void)
return err;
}

-static int f71862fg_pin_configure(unsigned short ioaddr)
-{
- /* When ioaddr is non-zero the calling function has to take care of
- mutex handling and superio preparation! */
-
- if (f71862fg_pin == 63) {
- if (ioaddr) {
- /* SPI must be disabled first to use this pin! */
- superio_clear_bit(ioaddr, SIO_REG_ROM_ADDR_SEL, 6);
- superio_set_bit(ioaddr, SIO_REG_MFUNCT3, 4);
- }
- } else if (f71862fg_pin == 56) {
- if (ioaddr)
- superio_set_bit(ioaddr, SIO_REG_MFUNCT1, 1);
- } else {
- pr_err("Invalid argument f71862fg_pin=%d\n", f71862fg_pin);
- return -EINVAL;
- }
- return 0;
-}
-
static int watchdog_start(void)
{
int err;
@@ -352,9 +331,13 @@ static int watchdog_start(void)
break;

case f71862fg:
- err = f71862fg_pin_configure(watchdog.sioaddr);
- if (err)
- goto exit_superio;
+ if (f71862fg_pin == 63) {
+ /* SPI must be disabled first to use this pin! */
+ superio_clear_bit(watchdog.sioaddr, SIO_REG_ROM_ADDR_SEL, 6);
+ superio_set_bit(watchdog.sioaddr, SIO_REG_MFUNCT3, 4);
+ } else if (f71862fg_pin == 56) {
+ superio_set_bit(watchdog.sioaddr, SIO_REG_MFUNCT1, 1);
+ }
break;

case f71868:
@@ -810,7 +793,6 @@ static int __init f71808e_find(int sioaddr)
break;
case SIO_F71862_ID:
watchdog.type = f71862fg;
- err = f71862fg_pin_configure(0); /* validate module parameter */
break;
case SIO_F71868_ID:
watchdog.type = f71868;
@@ -859,6 +841,11 @@ static int __init f71808e_init(void)
int err = -ENODEV;
int i;

+ if (f71862fg_pin != 63 && f71862fg_pin != 56) {
+ pr_err("Invalid argument f71862fg_pin=%d\n", f71862fg_pin);
+ return -EINVAL;
+ }
+
for (i = 0; i < ARRAY_SIZE(addrs); i++) {
err = f71808e_find(addrs[i]);
if (err == 0)
--
2.27.0
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