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add READ_ONCE() and WRITE_ONCE()

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This commit is contained in:
Bruno Raoult
2022-03-18 16:53:43 +01:00
parent 21e27ba16e
commit a92a4e04b4
2 changed files with 55 additions and 21 deletions
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43
c/list.h
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@@ -10,6 +10,7 @@
#include <stddef.h>
#include <stdbool.h>
#include "rwonce.h"
/************ originally in <include/linux/types.h> */
struct list_head {
@@ -61,7 +62,7 @@ struct hlist_node {
*/
static inline void INIT_LIST_HEAD(struct list_head *list)
{
list->next = list;
WRITE_ONCE(list->next, list);
list->prev = list;
}
@@ -78,7 +79,7 @@ static inline void __list_add(struct list_head *new,
next->prev = new;
new->next = next;
new->prev = prev;
prev->next = new;
WRITE_ONCE(prev->next, new);
}
/**
@@ -118,7 +119,7 @@ static inline void list_add_tail(struct list_head *new, struct list_head *head)
static inline void __list_del(struct list_head * prev, struct list_head * next)
{
next->prev = prev;
prev->next = next;
WRITE_ONCE(prev->next, next);
}
/*
@@ -284,7 +285,7 @@ static inline int list_is_last(const struct list_head *list,
*/
static inline int list_empty(const struct list_head *head)
{
return head->next == head;
return READ_ONCE(head->next) == head;
}
/**
@@ -510,7 +511,7 @@ static inline void list_splice_tail_init(struct list_head *list,
*/
#define list_first_entry_or_null(ptr, type, member) ({ \
struct list_head *head__ = (ptr); \
struct list_head *pos__ = head__->next; \
struct list_head *pos__ = READ_ONCE(head__->next); \
pos__ != head__ ? list_entry(pos__, type, member) : NULL; \
})
@@ -786,7 +787,7 @@ static inline int hlist_unhashed(const struct hlist_node *h)
*/
static inline int hlist_unhashed_lockless(const struct hlist_node *h)
{
return !h->pprev;
return !READ_ONCE(h->pprev);
}
/**
@@ -795,7 +796,7 @@ static inline int hlist_unhashed_lockless(const struct hlist_node *h)
*/
static inline int hlist_empty(const struct hlist_head *h)
{
return !h->first;
return !READ_ONCE(h->first);
}
static inline void __hlist_del(struct hlist_node *n)
@@ -803,9 +804,9 @@ static inline void __hlist_del(struct hlist_node *n)
struct hlist_node *next = n->next;
struct hlist_node **pprev = n->pprev;
*pprev = next;
WRITE_ONCE(*pprev, next);
if (next)
next->pprev = pprev;
WRITE_ONCE(next->pprev, pprev);
}
/**
@@ -847,11 +848,11 @@ static inline void hlist_del_init(struct hlist_node *n)
static inline void hlist_add_head(struct hlist_node *n, struct hlist_head *h)
{
struct hlist_node *first = h->first;
n->next = first;
WRITE_ONCE(n->next, first);
if (first)
first->pprev = &n->next;
h->first = n;
n->pprev = &h->first;
WRITE_ONCE(first->pprev, &n->next);
WRITE_ONCE(h->first, n);
WRITE_ONCE(n->pprev, &h->first);
}
/**
@@ -862,10 +863,10 @@ static inline void hlist_add_head(struct hlist_node *n, struct hlist_head *h)
static inline void hlist_add_before(struct hlist_node *n,
struct hlist_node *next)
{
n->pprev = next->pprev;
n->next = next;
next->pprev = &n->next;
*(n->pprev) = n;
WRITE_ONCE(n->pprev, next->pprev);
WRITE_ONCE(n->next, next);
WRITE_ONCE(next->pprev, &n->next);
WRITE_ONCE(*(n->pprev), n);
}
/**
@@ -876,12 +877,12 @@ static inline void hlist_add_before(struct hlist_node *n,
static inline void hlist_add_behind(struct hlist_node *n,
struct hlist_node *prev)
{
n->next = prev->next;
prev->next = n;
n->pprev = &prev->next;
WRITE_ONCE(n->next, prev->next);
WRITE_ONCE(prev->next, n);
WRITE_ONCE(n->pprev, &prev->next);
if (n->next)
n->next->pprev = &n->next;
WRITE_ONCE(n->next->pprev, &n->next);
}
/**