[PATCH v3 0/2] mm/slab: trivial fixup for SLAB_TYPESAFE_BY_RCU example code snippet

[PATCH v3 0/2] mm/slab: trivial fixup for SLAB_TYPESAFE_BY_RCU example code snippet

[SeongJae Park]

Changes from v2
(https://lore.kernel.org/linux-mm/20230415033159.4249-1-sj@kernel.org/)
- Wordsmith commit message of the second patch (Valstimil Babka)

Changes from v1
(https://lore.kernel.org/linux-mm/20230415003754.1852-1-sj@kernel.org/)
- Update label (s/again/begin/) correctly (Matthew Wilcox)
- Add missed rcu_read_unlock()

This patchset is for trivial fixup for SLAB_TYPESAFE_BY_RCU example code
snippet, namely adding missed semicolon and breaking RCU read-side
critical section into smaller ones.

SeongJae Park (2):
  mm/slab: add a missing semicolon on SLAB_TYPESAFE_BY_RCU example code
  mm/slab: break up RCU readers on SLAB_TYPESAFE_BY_RCU example code

 include/linux/slab.h | 10 ++++++----
 1 file changed, 6 insertions(+), 4 deletions(-)

-- 
2.25.1

[PATCH v3 1/2] mm/slab: add a missing semicolon on SLAB_TYPESAFE_BY_RCU example code

[SeongJae Park]

An example code snippet for SLAB_TYPESAFE_BY_RCU is missing a semicolon.
Add it.

Signed-off-by: SeongJae Park <sj@kernel.org>
---
 include/linux/slab.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/include/linux/slab.h b/include/linux/slab.h
index f8b1d63c63a3..b18e56c6f06c 100644
--- a/include/linux/slab.h
+++ b/include/linux/slab.h
@@ -53,7 +53,7 @@
  * stays valid, the trick to using this is relying on an independent
  * object validation pass. Something like:
  *
- *  rcu_read_lock()
+ *  rcu_read_lock();
  * again:
  *  obj = lockless_lookup(key);
  *  if (obj) {
-- 
2.25.1

[PATCH v3 2/2] mm/slab: break up RCU readers on SLAB_TYPESAFE_BY_RCU example code

[SeongJae Park]

The SLAB_TYPESAFE_BY_RCU example code snippet uses a single RCU
read-side critical section for retries.
'Documentation/RCU/rculist_nulls.rst' has similar example code snippet,
and commit da82af04352b ("doc: Update and wordsmith rculist_nulls.rst")
has broken it up.  Apply the change to SLAB_TYPESAFE_BY_RCU example code
snippet, too.

Signed-off-by: SeongJae Park <sj@kernel.org>
---
 include/linux/slab.h | 8 +++++---
 1 file changed, 5 insertions(+), 3 deletions(-)

diff --git a/include/linux/slab.h b/include/linux/slab.h
index b18e56c6f06c..6acf1b7c6551 100644
--- a/include/linux/slab.h
+++ b/include/linux/slab.h
@@ -53,16 +53,18 @@
  * stays valid, the trick to using this is relying on an independent
  * object validation pass. Something like:
  *
+ * begin:
  *  rcu_read_lock();
- * again:
  *  obj = lockless_lookup(key);
  *  if (obj) {
  *    if (!try_get_ref(obj)) // might fail for free objects
- *      goto again;
+ *      rcu_read_unlock();
+ *      goto begin;
  *
  *    if (obj->key != key) { // not the object we expected
  *      put_ref(obj);
- *      goto again;
+ *      rcu_read_unlock();
+ *      goto begin;
  *    }
  *  }
  *  rcu_read_unlock();
-- 
2.25.1