lockref: add a __cond_lock annotation for lockref_put_or_lock

Add a cond_lock annotation for lockref_put_or_lock to make sparse
happy with using it. Note that for this the return value has to be
double-inverted as the return value convention of lockref_put_or_lock
is inverted compared to _trylock conventions expected by __cond_lock,
as lockref_put_or_lock returns true when it did not need to take the
lock.

Signed-off-by: Christoph Hellwig <[e-mail]>
Signed-off-by: Linus Torvalds <[e-mail]>

include/linux/lockref.h

···
 int lockref_put_return(struct lockref *lockref);
 bool lockref_get_not_zero(struct lockref *lockref);
 bool lockref_put_or_lock(struct lockref *lockref);
+#define lockref_put_or_lock(_lockref) \
+	(!__cond_lock((_lockref)->lock, !lockref_put_or_lock(_lockref)))
 
 void lockref_mark_dead(struct lockref *lockref);
 bool lockref_get_not_dead(struct lockref *lockref);

lib/lockref.c

···
  * @lockref: pointer to lockref structure
  * Return: 1 if count updated successfully or 0 if count <= 1 and lock taken
  */
+#undef lockref_put_or_lock
 bool lockref_put_or_lock(struct lockref *lockref)
 {
 	CMPXCHG_LOOP(