[PATCH rcu 01/15] doc: Further updates to RCU's lockdep.rst

From: Paul E. McKenney
Date: Wed Jan 04 2023 - 19:10:01 EST


This commit wordsmiths RCU's lockdep.rst.

Signed-off-by: Paul E. McKenney <paulmck@xxxxxxxxxx>
---
Documentation/RCU/lockdep.rst | 13 ++++++-------
1 file changed, 6 insertions(+), 7 deletions(-)

diff --git a/Documentation/RCU/lockdep.rst b/Documentation/RCU/lockdep.rst
index 9308f1bdba05d..2749f43ec1b03 100644
--- a/Documentation/RCU/lockdep.rst
+++ b/Documentation/RCU/lockdep.rst
@@ -69,9 +69,8 @@ checking of rcu_dereference() primitives:
value of the pointer itself, for example, against NULL.

The rcu_dereference_check() check expression can be any boolean
-expression, but would normally include a lockdep expression. However,
-any boolean expression can be used. For a moderately ornate example,
-consider the following::
+expression, but would normally include a lockdep expression. For a
+moderately ornate example, consider the following::

file = rcu_dereference_check(fdt->fd[fd],
lockdep_is_held(&files->file_lock) ||
@@ -97,10 +96,10 @@ code, it could instead be written as follows::
atomic_read(&files->count) == 1);

This would verify cases #2 and #3 above, and furthermore lockdep would
-complain if this was used in an RCU read-side critical section unless one
-of these two cases held. Because rcu_dereference_protected() omits all
-barriers and compiler constraints, it generates better code than do the
-other flavors of rcu_dereference(). On the other hand, it is illegal
+complain even if this was used in an RCU read-side critical section unless
+one of these two cases held. Because rcu_dereference_protected() omits
+all barriers and compiler constraints, it generates better code than do
+the other flavors of rcu_dereference(). On the other hand, it is illegal
to use rcu_dereference_protected() if either the RCU-protected pointer
or the RCU-protected data that it points to can change concurrently.

--
2.31.1.189.g2e36527f23