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MINOR: lists: Implement locked variations.

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Implement LIST_ADD_LOCKED(), LIST_ADDQ_LOCKED(), LIST_DEL_LOCKED() and
LIST_POP_LOCKED().

LIST_ADD_LOCKED, LIST_ADDQ_LOCKED and LIST_DEL_LOCKED work the same as
LIST_ADD, LIST_ADDQ and LIST_DEL, except before any manipulation it locks
the relevant elements of the list, so it's safe to manipulate the list
with multiple threads.
LIST_POP_LOCKED() removes the first element from the list, and returns its
data.
This commit is contained in:
Olivier Houchard 2019-01-18 17:26:26 +01:00 committed by Olivier Houchard
parent 36839dc39f
commit a8434ec146
1 changed files with 144 additions and 0 deletions
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144
include/common/mini-clist.h
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@ -163,5 +163,149 @@ struct cond_wordlist {
&item->member != (list_head); \
item = back, back = LIST_ELEM(back->member.n, typeof(back), member))
#include <common/hathreads.h>
#define LLIST_BUSY ((struct list *)1)
/*
* Locked version of list manipulation macros.
* It is OK to use those concurrently from multiple threads, as long as the
* list is only used with the locked variants. The only "unlocked" macro you
* can use with a locked list is LIST_INIT.
*/
#define LIST_ADD_LOCKED(lh, el) \
do { \
while (1) { \
struct list *n; \
struct list *p; \
n = HA_ATOMIC_XCHG(&(lh)->n, LLIST_BUSY); \
if (n == LLIST_BUSY) \
continue; \
__ha_barrier_store(); \
p = HA_ATOMIC_XCHG(&n->p, LLIST_BUSY); \
if (p == LLIST_BUSY) { \
(lh)->n = n; \
__ha_barrier_store(); \
continue; \
} \
(el)->n = n; \
(el)->p = p; \
n->p = (el); \
__ha_barrier_store(); \
p->n = (el); \
__ha_barrier_store(); \
break; \
} \
} while (0)
#define LIST_ADDQ_LOCKED(lh, el) \
do { \
while (1) { \
struct list *n; \
struct list *p; \
p = HA_ATOMIC_XCHG(&(lh)->p, LLIST_BUSY); \
if (p == LLIST_BUSY) \
continue; \
__ha_barrier_store(); \
n = HA_ATOMIC_XCHG(&p->n, LLIST_BUSY); \
if (n == LLIST_BUSY) { \
(lh)->n = p; \
__ha_barrier_store(); \
continue; \
} \
(el)->n = n; \
(el)->p = p; \
n->p = (el); \
__ha_barrier_store(); \
p->n = (el); \
__ha_barrier_store(); \
break; \
} \
} while (0)
#define LIST_DEL_LOCKED(el) \
do { \
while (1) { \
struct list *n, *n2; \
struct list *p, *p2; \
n = HA_ATOMIC_XCHG(&(el)->n, LLIST_BUSY); \
if (n == LLIST_BUSY) \
continue; \
p = HA_ATOMIC_XCHG(&(el)->p, LLIST_BUSY); \
if (p == LLIST_BUSY) { \
(el)->n = n; \
__ha_barrier_store(); \
continue; \
} \
if (p != (el)) { \
p2 = HA_ATOMIC_XCHG(&p->n, LLIST_BUSY); \
if (p2 == LLIST_BUSY) { \
(el)->p = p; \
(el)->n = n; \
__ha_barrier_store(); \
continue; \
} \
} \
if (n != (el)) { \
n2 = HA_ATOMIC_XCHG(&n->p, LLIST_BUSY); \
if (n2 == LLIST_BUSY) { \
p2->n = (el); \
(el)->p = p; \
(el)->n = n; \
__ha_barrier_store(); \
continue; \
} \
} \
n->p = p; \
p->n = n; \
__ha_barrier_store(); \
break; \
} \
} while (0)
/* Remove the first element from the list, and return it */
#define LIST_POP_LOCKED(lh, pt, el) \
({ \
void *_ret; \
while (1) { \
struct list *n, *n2; \
struct list *p, *p2; \
n = HA_ATOMIC_XCHG(&(lh)->n, LLIST_BUSY); \
if (n == LLIST_BUSY) \
continue; \
if (n == (lh)) { \
(lh)->n = lh; \
_ret = NULL; \
break; \
} \
p = HA_ATOMIC_XCHG(&n->p, LLIST_BUSY); \
if (p == LLIST_BUSY) { \
(lh)->n = n; \
__ha_barrier_store(); \
continue; \
} \
n2 = HA_ATOMIC_XCHG(&n->n, LLIST_BUSY); \
if (n2 == LLIST_BUSY) { \
n->p = p; \
(lh)->n = n; \
__ha_barrier_store(); \
continue; \
} \
p2 = HA_ATOMIC_XCHG(&n2->p, LLIST_BUSY); \
if (p2 == LLIST_BUSY) { \
n->n = n2; \
n->p = p; \
(lh)->n = n; \
__ha_barrier_store(); \
continue; \
} \
(lh)->n = n2; \
(n2)->p = (lh); \
__ha_barrier_store(); \
_ret = LIST_ELEM(n, pt, el); \
break; \
} \
(_ret); \
})
#endif /* _COMMON_MINI_CLIST_H */