[PATCH v3 2/3] Documentation: RCU: adopt new coding style of type-aware kmalloc-family

Manuel Ebner
2026-04-25T05:46:56Z

Update Documentation/RCU/* to reflect new type-aware kmalloc-family
as suggested in commit 2932ba8d9c99 ("slab: Introduce kmalloc_obj()
and family")

ptr = kmalloc(sizeof(*ptr), gfp);
-> ptr = kmalloc_obj(*ptr);

Signed-off-by: Manuel Ebner <manuelebner@mailbox.org>
Acked-by: Paul E. McKenney <paulmck@kernel.org>
---
in the prior mail i forgot the e-mail address of Paul
Acked-by see
https://lore.kernel.org/linux-doc/7a49fee0-09c8-4a48-9506-d9172ef024b0@paulmck-laptop/

Documentation/RCU/Design/Requirements/Requirements.rst | 6 +++---
Documentation/RCU/listRCU.rst | 2 +-
Documentation/RCU/whatisRCU.rst | 4 ++--
3 files changed, 6 insertions(+), 6 deletions(-)

diff --git a/Documentation/RCU/Design/Requirements/Requirements.rst b/Documentation/RCU/Design/Requirements/Requirements.rst
index b5cdbba3ec2e..faca5a9c8c12 100644
--- a/Documentation/RCU/Design/Requirements/Requirements.rst
+++ b/Documentation/RCU/Design/Requirements/Requirements.rst
@@ -206,7 +206,7 @@ non-\ ``NULL``, locklessly accessing the ``->a`` and ``->b`` fields.

1 bool add_gp_buggy(int a, int b)
2 {
- 3 p = kmalloc(sizeof(*p), GFP_KERNEL);
+ 3 p = kmalloc_obj(*p);
4 if (!p)
5 return -ENOMEM;
6 spin_lock(&gp_lock);
@@ -228,7 +228,7 @@ their rights to reorder this code as follows:

1 bool add_gp_buggy_optimized(int a, int b)
2 {
- 3 p = kmalloc(sizeof(*p), GFP_KERNEL);
+ 3 p = kmalloc_obj(*p);
4 if (!p)
5 return -ENOMEM;
6 spin_lock(&gp_lock);
@@ -264,7 +264,7 @@ shows an example of insertion:

1 bool add_gp(int a, int b)
2 {
- 3 p = kmalloc(sizeof(*p), GFP_KERNEL);
+ 3 p = kmalloc_obj(*p);
4 if (!p)
5 return -ENOMEM;
6 spin_lock(&gp_lock);
diff --git a/Documentation/RCU/listRCU.rst b/Documentation/RCU/listRCU.rst
index d8bb98623c12..48c7272a4ccc 100644
--- a/Documentation/RCU/listRCU.rst
+++ b/Documentation/RCU/listRCU.rst
@@ -276,7 +276,7 @@ The RCU version of audit_upd_rule() is as follows::

list_for_each_entry(e, list, list) {
if (!audit_compare_rule(rule, &e->rule)) {
- ne = kmalloc(sizeof(*entry), GFP_ATOMIC);
+ ne = kmalloc_obj(*entry, GFP_ATOMIC);
if (ne == NULL)
return -ENOMEM;
audit_copy_rule(&ne->rule, &e->rule);
diff --git a/Documentation/RCU/whatisRCU.rst b/Documentation/RCU/whatisRCU.rst
index a1582bd653d1..770aab8ea36a 100644
--- a/Documentation/RCU/whatisRCU.rst
+++ b/Documentation/RCU/whatisRCU.rst
@@ -468,7 +468,7 @@ uses of RCU may be found in listRCU.rst and NMI-RCU.rst.
struct foo *new_fp;
struct foo *old_fp;

- new_fp = kmalloc(sizeof(*new_fp), GFP_KERNEL);
+ new_fp = kmalloc_obj(*new_fp);
spin_lock(&foo_mutex);
old_fp = rcu_dereference_protected(gbl_foo, lockdep_is_held(&foo_mutex));
*new_fp = *old_fp;
@@ -570,7 +570,7 @@ The foo_update_a() function might then be written as follows::
struct foo *new_fp;
struct foo *old_fp;

- new_fp = kmalloc(sizeof(*new_fp), GFP_KERNEL);
+ new_fp = kmalloc_obj(*new_fp);
spin_lock(&foo_mutex);
old_fp = rcu_dereference_protected(gbl_foo, lockdep_is_held(&foo_mutex));
*new_fp = *old_fp;
--
2.53.0