watchdog: ts72xx_wdt: cleanup return codes in ioctl

There seems to be some confusion here which functions return positive
numbers and which return negative error codes.

copy_to_user() returns the number of bytes remaining to be copied but we
want to return -EFAULT.

The rest is just clean up.  get_user() actually returns zero on success
and -EFAULT on error so we can preserve the error code.  The
timeout_to_regval() function returns -EINVAL on failure, but we can
propogate that back instead of hardcoding -EINVAL ourselves.

Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>
--

1 files changed, 16 insertions, 20 deletions

diff --git a/drivers/watchdog/ts72xx_wdt.c b/drivers/watchdog/ts72xx_wdt.c
index c9b0c627fe7e..df5dd55b9b3a 100644
--- a/drivers/watchdog/ts72xx_wdt.c
+++ b/drivers/watchdog/ts72xx_wdt.c
@@ -305,7 +305,8 @@ static long ts72xx_wdt_ioctl(struct file *file, unsigned int cmd,
 
         switch (cmd) {
         case WDIOC_GETSUPPORT:
-                error = copy_to_user(argp, &winfo, sizeof(winfo));
+                if (copy_to_user(argp, &winfo, sizeof(winfo)))
+                        error = -EFAULT;
                 break;
 
         case WDIOC_GETSTATUS:
@@ -320,10 +321,9 @@ static long ts72xx_wdt_ioctl(struct file *file, unsigned int cmd,
         case WDIOC_SETOPTIONS: {
                 int options;
 
-                if (get_user(options, p)) {
-                        error = -EFAULT;
+                error = get_user(options, p);
+                if (error)
                         break;
-                }
 
                 error = -EINVAL;
 
@@ -341,30 +341,26 @@ static long ts72xx_wdt_ioctl(struct file *file, unsigned int cmd,
 
         case WDIOC_SETTIMEOUT: {
                 int new_timeout;
+                int regval;
 
-                if (get_user(new_timeout, p)) {
-                        error = -EFAULT;
-                } else {
-                        int regval;
-
-                        regval = timeout_to_regval(new_timeout);
-                        if (regval < 0) {
-                                error = -EINVAL;
-                        } else {
-                                ts72xx_wdt_stop(wdt);
-                                wdt->regval = regval;
-                                ts72xx_wdt_start(wdt);
-                        }
-                }
+                error = get_user(new_timeout, p);
                 if (error)
                         break;
 
+                regval = timeout_to_regval(new_timeout);
+                if (regval < 0) {
+                        error = regval;
+                        break;
+                }
+                ts72xx_wdt_stop(wdt);
+                wdt->regval = regval;
+                ts72xx_wdt_start(wdt);
+
                 /*FALLTHROUGH*/
         }
 
         case WDIOC_GETTIMEOUT:
-                if (put_user(regval_to_timeout(wdt->regval), p))
-                        error = -EFAULT;
+                error = put_user(regval_to_timeout(wdt->regval), p);
                 break;
 
         default: