Kernel/linux-next
1
0
Fork 0
mirror of https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git synced 2025-01-01 10:42:11 +00:00
Code Issues Actions Packages Projects Releases Wiki Activity

Docs/RCU/rculist_nulls: Fix hlist_[nulls]_head field names of 'obj'

Browse Source 
The example code snippets on rculist_nulls.rst are assuming 'obj' to
have the 'hlist_head' or 'hlist_nulls_head' field named 'obj_node', but
a sentence and some code snippets are wrongly calling
'obj->obj_node.next' as 'obj->obj_next', or 'obj->obj_node' as 'member'.
Fix it.

Signed-off-by: SeongJae Park <sj@kernel.org>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
This commit is contained in:
SeongJae Park 2023-06-16 23:36:25 +00:00 committed by Paul E. McKenney
parent 5326caa7a1
commit d186204a98
1 changed files with 4 additions and 4 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

8
Documentation/RCU/rculist_nulls.rst
View File

@ -65,7 +65,7 @@ but a version with an additional memory barrier (smp_rmb())
struct hlist_node *node, *next; struct hlist_node *node, *next;
for (pos = rcu_dereference((head)->first); for (pos = rcu_dereference((head)->first);
pos && ({ next = pos->next; smp_rmb(); prefetch(next); 1; }) && pos && ({ next = pos->next; smp_rmb(); prefetch(next); 1; }) &&
({ obj = hlist_entry(pos, typeof(*obj), member); 1; }); ({ obj = hlist_entry(pos, typeof(*obj), obj_node); 1; });
pos = rcu_dereference(next)) pos = rcu_dereference(next))
if (obj->key == key) if (obj->key == key)
return obj; return obj;
@ -77,7 +77,7 @@ And note the traditional hlist_for_each_entry_rcu() misses this smp_rmb()::
struct hlist_node *node; struct hlist_node *node;
for (pos = rcu_dereference((head)->first); for (pos = rcu_dereference((head)->first);
pos && ({ prefetch(pos->next); 1; }) && pos && ({ prefetch(pos->next); 1; }) &&
({ obj = hlist_entry(pos, typeof(*obj), member); 1; }); ({ obj = hlist_entry(pos, typeof(*obj), obj_node); 1; });
pos = rcu_dereference(pos->next)) pos = rcu_dereference(pos->next))
if (obj->key == key) if (obj->key == key)
return obj; return obj;
@ -97,7 +97,7 @@ Quoting Corey Minyard::
2) Insertion algorithm 2) Insertion algorithm
---------------------- ----------------------
We need to make sure a reader cannot read the new 'obj->obj_next' value We need to make sure a reader cannot read the new 'obj->obj_node.next' value
and previous value of 'obj->key'. Otherwise, an item could be deleted and previous value of 'obj->key'. Otherwise, an item could be deleted
from a chain, and inserted into another chain. If new chain was empty from a chain, and inserted into another chain. If new chain was empty
before the move, 'next' pointer is NULL, and lockless reader can not before the move, 'next' pointer is NULL, and lockless reader can not
@ -165,7 +165,7 @@ Note that using hlist_nulls means the type of 'obj_node' field of
head = &table[slot]; head = &table[slot];
begin: begin:
rcu_read_lock(); rcu_read_lock();
hlist_nulls_for_each_entry_rcu(obj, node, head, member) { hlist_nulls_for_each_entry_rcu(obj, node, head, obj_node) {
if (obj->key == key) { if (obj->key == key) {
if (!try_get_ref(obj)) { // might fail for free objects if (!try_get_ref(obj)) { // might fail for free objects
rcu_read_unlock(); rcu_read_unlock();