kernel/params.c: downgrade warning for unsafe parameters

As using an unsafe module parameter is, by its very definition, an
expected user action, emitting a warning is overkill.  Nothing has yet
gone wrong, and we add a taint flag for any future oops should something
actually go wrong.  So instead of having a user controllable pr_warn,
downgrade it to a pr_notice for "a normal, but significant condition".

We make use of unsafe kernel parameters in igt
(https://cgit.freedesktop.org/drm/igt-gpu-tools/) (we have not yet
succeeded in removing all such debugging options), which generates a
warning and taints the kernel.  The warning is unhelpful as we then need
to filter it out again as we check that every test themselves do not
provoke any kernel warnings.

Link: http://lkml.kernel.org/r/[email protected]
Fixes: 91f9d33 ("module: make it possible to have unsafe, tainting module params")
Signed-off-by: Chris Wilson <[email protected]>
Acked-by: Jani Nikula <[email protected]>
Reviewed-by: Andrew Morton <[email protected]>
Cc: Rusty Russell <[email protected]>
Cc: Jean Delvare <[email protected]>
Cc: Li Zhong <[email protected]>
Cc: Petri Latvala <[email protected]>
Cc: Daniel Vetter <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>

kernel/params.c

@@ -111,8 +111,8 @@ bool parameq(const char *a, const char *b)
 static void param_check_unsafe(const struct kernel_param *kp)
 {
 	if (kp->flags & KERNEL_PARAM_FL_UNSAFE) {
-		pr_warn("Setting dangerous option %s - tainting kernel\n",
-			kp->name);
+		pr_notice("Setting dangerous option %s - tainting kernel\n",
+			  kp->name);
 		add_taint(TAINT_USER, LOCKDEP_STILL_OK);
 	}
 }