rcu: Remove rcu_swap_protected()

Now that the calls to rcu_swap_protected() have been replaced by
rcu_replace_pointer(), this commit removes rcu_swap_protected().

Link: https://lore.kernel.org/lkml/CAHk-=wiAsJLw1egFEE=Z7-GGtM6wcvtyytXZA1+BHqta4gg6Hw@mail.gmail.com/
Reported-by: Linus Torvalds <[email protected]>
Signed-off-by: Paul E. McKenney <[email protected]>
Cc: Bart Van Assche <[email protected]>
Cc: Christoph Hellwig <[email protected]>
Cc: Hannes Reinecke <[email protected]>
Cc: Johannes Thumshirn <[email protected]>
Cc: Shane M Seymour <[email protected]>
Cc: Martin K. Petersen <[email protected]>

Author: paulmckrcu

include/linux/rcupdate.h

@@ -400,22 +400,6 @@ do {									      \
 	__tmp;								\
 })
 
-/**
- * rcu_swap_protected() - swap an RCU and a regular pointer
- * @rcu_ptr: RCU pointer
- * @ptr: regular pointer
- * @c: the conditions under which the dereference will take place
- *
- * Perform swap(@rcu_ptr, @ptr) where @rcu_ptr is an RCU-annotated pointer and
- * @c is the argument that is passed to the rcu_dereference_protected() call
- * used to read that pointer.
- */
-#define rcu_swap_protected(rcu_ptr, ptr, c) do {			\
-	typeof(ptr) __tmp = rcu_dereference_protected((rcu_ptr), (c));	\
-	rcu_assign_pointer((rcu_ptr), (ptr));				\
-	(ptr) = __tmp;							\
-} while (0)
-
 /**
  * rcu_access_pointer() - fetch RCU pointer with no dereferencing
  * @p: The pointer to read