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LinuxKPI: Add compiler barriers to list_for_each_entry_lockless macro

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so this list-traversal primitive may safely run concurrently with the
_rcu list-mutation primitives such as list_add_rcu() as long as the
traversal is guarded by rcu_read_lock().

Do it by reusing the "list_for_each_entry_rcu" macro which does the same.
On Linux it implements some additional lockdep stuff which we skip.

Also move the macro to linux/rculist.h where it resides on Linux.

Reviewed by:	hselasky
Differential revision:	https://reviews.freebsd.org/D30795
This commit is contained in:
Vladimir Kondratyev 2021-07-05 03:19:35 +03:00
parent c77ec79b57
commit c0862b2b1f
2 changed files with 3 additions and 2 deletions
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2
sys/compat/linuxkpi/common/include/linux/list.h
View File

@ -202,8 +202,6 @@ list_del_init(struct list_head *entry)
for (p = list_entry((h)->next, typeof(*p), field); &(p)->field != (h); \
p = list_entry((p)->field.next, typeof(*p), field))
#define list_for_each_entry_lockless(...) list_for_each_entry(__VA_ARGS__)
#define list_for_each_entry_safe(p, n, h, field) \
for (p = list_entry((h)->next, typeof(*p), field), \
n = list_entry((p)->field.next, typeof(*p), field); &(p)->field != (h);\

3
sys/compat/linuxkpi/common/include/linux/rculist.h
View File

@ -44,6 +44,9 @@
&(pos)->member != (head); \
pos = list_entry_rcu((pos)->member.next, typeof(*(pos)), member))
#define list_for_each_entry_lockless(pos, head, member) \
list_for_each_entry_rcu(pos, head, member)
static inline void
linux_list_add_rcu(struct list_head *new, struct list_head *prev,
struct list_head *next)