module_param: avoid bool abuse, add bint for special cases.

For historical reasons, we allow module_param(bool) to take an int (or
an unsigned int).  That's going away.

A few drivers really want an int: they set it to -1 and a parameter
will set it to 0 or 1.  This sucks: reading them from sysfs will give
'Y' for both -1 and 1, but if we change it to an int, then the users
might be broken (if they did "param" instead of "param=1").

Use a new 'bint' parser for them.

(ntfs has a different problem: it needs an int for debug_msgs because
it's also exposed via sysctl.)

Cc: Steve Glendinning <steve.glendinning@smsc.com>
Cc: Jean Delvare <khali@linux-fr.org>
Cc: Guenter Roeck <guenter.roeck@ericsson.com>
Cc: Hoang-Nam Nguyen <hnguyen@de.ibm.com>
Cc: Christoph Raisch <raisch@de.ibm.com>
Cc: Roland Dreier <roland@kernel.org>
Cc: Sean Hefty <sean.hefty@intel.com>
Cc: Hal Rosenstock <hal.rosenstock@gmail.com>
Cc: linux390@de.ibm.com
Cc: Anton Altaparmakov <anton@tuxera.com>
Cc: Jaroslav Kysela <perex@perex.cz>
Cc: Takashi Iwai <tiwai@suse.de>
Cc: lm-sensors@lm-sensors.org
Cc: linux-rdma@vger.kernel.org
Cc: linux-s390@vger.kernel.org
Cc: linux-ntfs-dev@lists.sourceforge.net
Cc: alsa-devel@alsa-project.org
Acked-by: Takashi Iwai <tiwai@suse.de> (For the sound part)
Acked-by: Guenter Roeck <guenter.roeck@ericsson.com> (For the hwmon driver)
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>

1 files changed, 24 insertions, 0 deletions

diff --git a/kernel/params.c b/kernel/params.c
index 9240664af110..32ee04308285 100644
--- a/kernel/params.c
+++ b/kernel/params.c
@@ -363,6 +363,30 @@ struct kernel_param_ops param_ops_invbool = {
 };
 EXPORT_SYMBOL(param_ops_invbool);
 
+int param_set_bint(const char *val, const struct kernel_param *kp)
+{
+        struct kernel_param boolkp;
+        bool v;
+        int ret;
+
+        /* Match bool exactly, by re-using it. */
+        boolkp = *kp;
+        boolkp.arg = &v;
+        boolkp.flags |= KPARAM_ISBOOL;
+
+        ret = param_set_bool(val, &boolkp);
+        if (ret == 0)
+                *(int *)kp->arg = v;
+        return ret;
+}
+EXPORT_SYMBOL(param_set_bint);
+
+struct kernel_param_ops param_ops_bint = {
+        .set = param_set_bint,
+        .get = param_get_int,
+};
+EXPORT_SYMBOL(param_ops_bint);
+
 /* We break the rule and mangle the string. */
 static int param_array(const char *name,
                        const char *val,