rcu: Remove srcu_read_lock_raw() and srcu_read_unlock_raw().

These interfaces never did get used, so this commit removes them,
their rcutorture tests, and documentation referencing them.

Signed-off-by: Paul E. McKenney <[email protected]>
Reviewed-by: Lai Jiangshan <[email protected]>
Reviewed-by: Josh Triplett <[email protected]>

Documentation/RCU/checklist.txt

@@ -354,12 +354,6 @@ over a rather long period of time, but improvements are always welcome!
 	using RCU rather than SRCU, because RCU is almost always faster
 	and easier to use than is SRCU.
 
-	If you need to enter your read-side critical section in a
-	hardirq or exception handler, and then exit that same read-side
-	critical section in the task that was interrupted, then you need
-	to srcu_read_lock_raw() and srcu_read_unlock_raw(), which avoid
-	the lockdep checking that would otherwise this practice illegal.
-
 	Also unlike other forms of RCU, explicit initialization
 	and cleanup is required via init_srcu_struct() and
 	cleanup_srcu_struct().	These are passed a "struct srcu_struct"

Documentation/RCU/torture.txt

@@ -182,12 +182,6 @@ torture_type	The type of RCU to test, with string values as follows:
 		"srcu_expedited": srcu_read_lock(), srcu_read_unlock() and
 			synchronize_srcu_expedited().
 
-		"srcu_raw": srcu_read_lock_raw(), srcu_read_unlock_raw(),
-			and call_srcu().
-
-		"srcu_raw_sync": srcu_read_lock_raw(), srcu_read_unlock_raw(),
-			and synchronize_srcu().
-
 		"sched": preempt_disable(), preempt_enable(), and
 			call_rcu_sched().
 

Documentation/RCU/whatisRCU.txt

@@ -842,9 +842,7 @@ SRCU:	Critical sections	Grace period		Barrier
 
 	srcu_read_lock		synchronize_srcu	srcu_barrier
 	srcu_read_unlock	call_srcu
-	srcu_read_lock_raw	synchronize_srcu_expedited
-	srcu_read_unlock_raw
-	srcu_dereference
+	srcu_dereference	synchronize_srcu_expedited
 
 SRCU:	Initialization/cleanup
 	init_srcu_struct
@@ -865,38 +863,32 @@ list can be helpful:
 
 a.	Will readers need to block?  If so, you need SRCU.
 
-b.	Is it necessary to start a read-side critical section in a
-	hardirq handler or exception handler, and then to complete
-	this read-side critical section in the task that was
-	interrupted?  If so, you need SRCU's srcu_read_lock_raw() and
-	srcu_read_unlock_raw() primitives.
-
-c.	What about the -rt patchset?  If readers would need to block
+b.	What about the -rt patchset?  If readers would need to block
 	in an non-rt kernel, you need SRCU.  If readers would block
 	in a -rt kernel, but not in a non-rt kernel, SRCU is not
 	necessary.
 
-d.	Do you need to treat NMI handlers, hardirq handlers,
+c.	Do you need to treat NMI handlers, hardirq handlers,
 	and code segments with preemption disabled (whether
 	via preempt_disable(), local_irq_save(), local_bh_disable(),
 	or some other mechanism) as if they were explicit RCU readers?
 	If so, RCU-sched is the only choice that will work for you.
 
-e.	Do you need RCU grace periods to complete even in the face
+d.	Do you need RCU grace periods to complete even in the face
 	of softirq monopolization of one or more of the CPUs?  For
 	example, is your code subject to network-based denial-of-service
 	attacks?  If so, you need RCU-bh.
 
-f.	Is your workload too update-intensive for normal use of
+e.	Is your workload too update-intensive for normal use of
 	RCU, but inappropriate for other synchronization mechanisms?
 	If so, consider SLAB_DESTROY_BY_RCU.  But please be careful!
 
-g.	Do you need read-side critical sections that are respected
+f.	Do you need read-side critical sections that are respected
 	even though they are in the middle of the idle loop, during
 	user-mode execution, or on an offlined CPU?  If so, SRCU is the
 	only choice that will work for you.
 
-h.	Otherwise, use RCU.
+g.	Otherwise, use RCU.
 
 Of course, this all assumes that you have determined that RCU is in fact
 the right tool for your job.