power management: force pm_ops.valid callback to be assigned

This patch changes the docs and behaviour from "all states valid" to "no
states valid" if no .valid callback is assigned.  Users of pm_ops that only
need mem sleep can assign pm_valid_only_mem without any overhead, others
will require more elaborate callbacks.

Now that all users of pm_ops have a .valid callback this is a safe thing to
do and prevents things from getting messy again as they were before.

Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Acked-by: Pavel Machek <pavel@ucw.cz>
Looks-okay-to: Rafael J. Wysocki <rjw@sisk.pl>
Cc: <linux-pm@lists.linux-foundation.org>
Cc: Greg KH <greg@kroah.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 2 insertions, 2 deletions

diff --git a/kernel/power/main.c b/kernel/power/main.c
index f94f4e2..72419a3 100644
--- a/kernel/power/main.c
+++ b/kernel/power/main.c
@@ -198,8 +198,8 @@ static inline int valid_state(suspend_state_t state)
 
 	/* all other states need lowlevel support and need to be
 	 * valid to the lowlevel implementation, no valid callback
-	 * implies that all are valid. */
-	if (!pm_ops || (pm_ops->valid && !pm_ops->valid(state)))
+	 * implies that none are valid. */
+	if (!pm_ops || !pm_ops->valid || !pm_ops->valid(state))
 		return 0;
 	return 1;
 }