path: root/Documentation/RCU
diff options
authorKees Cook <keescook@chromium.org>2012-10-19 09:48:30 -0700
committerPaul E. McKenney <paulmck@linux.vnet.ibm.com>2012-11-08 11:44:25 -0800
commit57d34a6cee1399bfedaa73add1915951cbe75cab (patch)
treeb1ace739f62f0e8217b4213a8cdda9fc46f9b27e /Documentation/RCU
parent0f9574d83234274c4d8f8f742b45022e5718b16e (diff)
rcu: Update docs to include kfree_rcu()
Mention kfree_rcu() in the call_rcu() section. Additionally fix the example code for list replacement that used the wrong structure element. Signed-off-by: Kees Cook <keescook@chromium.org> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Diffstat (limited to 'Documentation/RCU')
2 files changed, 12 insertions, 3 deletions
diff --git a/Documentation/RCU/listRCU.txt b/Documentation/RCU/listRCU.txt
index 4349c1487e91..adb5a3782846 100644
--- a/Documentation/RCU/listRCU.txt
+++ b/Documentation/RCU/listRCU.txt
@@ -205,7 +205,7 @@ RCU ("read-copy update") its name. The RCU code is as follows:
audit_copy_rule(&ne->rule, &e->rule);
ne->rule.action = newaction;
ne->rule.file_count = newfield_count;
- list_replace_rcu(e, ne);
+ list_replace_rcu(&e->list, &ne->list);
call_rcu(&e->rcu, audit_free_rule);
return 0;
diff --git a/Documentation/RCU/whatisRCU.txt b/Documentation/RCU/whatisRCU.txt
index bf0f6de2aa00..160ac5557e97 100644
--- a/Documentation/RCU/whatisRCU.txt
+++ b/Documentation/RCU/whatisRCU.txt
@@ -499,6 +499,8 @@ The foo_reclaim() function might appear as follows:
struct foo *fp = container_of(rp, struct foo, rcu);
+ foo_cleanup(fp->a);
@@ -521,6 +523,12 @@ o Use call_rcu() -after- removing a data element from an
read-side critical sections that might be referencing that
data item.
+If the callback for call_rcu() is not doing anything more than calling
+kfree() on the structure, you can use kfree_rcu() instead of call_rcu()
+to avoid having to write your own callback:
+ kfree_rcu(old_fp, rcu);
Again, see checklist.txt for additional rules governing the use of RCU.
@@ -773,8 +781,8 @@ a single atomic update, converting to RCU will require special care.
Also, the presence of synchronize_rcu() means that the RCU version of
delete() can now block. If this is a problem, there is a callback-based
-mechanism that never blocks, namely call_rcu(), that can be used in
-place of synchronize_rcu().
+mechanism that never blocks, namely call_rcu() or kfree_rcu(), that can
+be used in place of synchronize_rcu().
@@ -813,6 +821,7 @@ RCU: Critical sections Grace period Barrier
rcu_read_unlock synchronize_rcu
rcu_dereference synchronize_rcu_expedited
+ kfree_rcu
bh: Critical sections Grace period Barrier

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