rcu: Remove SPARSE_RCU_POINTER Kconfig option

The sparse-based checking for non-RCU accesses to RCU-protected pointers
has been around for a very long time, and it is now the only type of
sparse-based checking that is optional.  This commit therefore makes
it unconditional.

Reported-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Fengguang Wu <fengguang.wu@intel.com>

3 files changed, 7 insertions, 16 deletions

diff --git a/Documentation/RCU/Design/Requirements/Requirements.html b/Documentation/RCU/Design/Requirements/Requirements.html
index 8c94fc1d1c84..0e6550a8c926 100644
--- a/Documentation/RCU/Design/Requirements/Requirements.html
+++ b/Documentation/RCU/Design/Requirements/Requirements.html
@@ -559,9 +559,7 @@ The <tt>rcu_access_pointer()</tt> on line&nbsp;6 is similar to
 	For <tt>remove_gp_synchronous()</tt>, as long as all modifications
 	to <tt>gp</tt> are carried out while holding <tt>gp_lock</tt>,
 	the above optimizations are harmless.
-	However,
-	with <tt>CONFIG_SPARSE_RCU_POINTER=y</tt>,
-	<tt>sparse</tt> will complain if you
+	However, <tt>sparse</tt> will complain if you
 	define <tt>gp</tt> with <tt>__rcu</tt> and then
 	access it without using
 	either <tt>rcu_access_pointer()</tt> or <tt>rcu_dereference()</tt>.
@@ -1978,9 +1976,8 @@ guard against mishaps and misuse:
 	and <tt>rcu_dereference()</tt>, perhaps (incorrectly)
 	substituting a simple assignment.
 	To catch this sort of error, a given RCU-protected pointer may be
-	tagged with <tt>__rcu</tt>, after which running sparse
-	with <tt>CONFIG_SPARSE_RCU_POINTER=y</tt> will complain
-	about simple-assignment accesses to that pointer.
+	tagged with <tt>__rcu</tt>, after which sparse
+	will complain about simple-assignment accesses to that pointer.
 	Arnd Bergmann made me aware of this requirement, and also
 	supplied the needed
 	<a href="https://lwn.net/Articles/376011/">patch series</a>.
diff --git a/Documentation/RCU/checklist.txt b/Documentation/RCU/checklist.txt
index 877947130ebe..6beda556faf3 100644
--- a/Documentation/RCU/checklist.txt
+++ b/Documentation/RCU/checklist.txt
@@ -413,11 +413,11 @@ over a rather long period of time, but improvements are always welcome!
 	read-side critical sections.  It is the responsibility of the
 	RCU update-side primitives to deal with this.
 
-17.	Use CONFIG_PROVE_RCU, CONFIG_DEBUG_OBJECTS_RCU_HEAD, and the
-	__rcu sparse checks (enabled by CONFIG_SPARSE_RCU_POINTER) to
-	validate your RCU code.  These can help find problems as follows:
+17.	Use CONFIG_PROVE_LOCKING, CONFIG_DEBUG_OBJECTS_RCU_HEAD, and the
+	__rcu sparse checks to validate your RCU code.	These can help
+	find problems as follows:
 
-	CONFIG_PROVE_RCU: check that accesses to RCU-protected data
+	CONFIG_PROVE_LOCKING: check that accesses to RCU-protected data
 		structures are carried out under the proper RCU
 		read-side critical section, while holding the right
 		combination of locks, or whatever other conditions
diff --git a/Documentation/dev-tools/sparse.rst b/Documentation/dev-tools/sparse.rst
index ffdcc97f6f5a..78aa00a604a0 100644
--- a/Documentation/dev-tools/sparse.rst
+++ b/Documentation/dev-tools/sparse.rst
@@ -103,9 +103,3 @@ have already built it.
 
 The optional make variable CF can be used to pass arguments to sparse.  The
 build system passes -Wbitwise to sparse automatically.
-
-Checking RCU annotations
-~~~~~~~~~~~~~~~~~~~~~~~~
-
-RCU annotations are not checked by default.  To enable RCU annotation
-checks, include -DCONFIG_SPARSE_RCU_POINTER in your CF flags.