Commit 945d9c75 authored by Emilio G. Cota's avatar Emilio G. Cota Committed by Paolo Bonzini
Browse files

rcu_queue: add RCU QTAILQ 



Signed-off-by: default avatarEmilio G. Cota <cota@braap.org>
Message-Id: <20180819091335.22863-5-cota@braap.org>
Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
parent 13d8ef7d

include/qemu/rcu_queue.h

+66 −0
Original line number Diff line number Diff line
@@ -193,6 +193,72 @@ extern "C" { 
         (var) && ((next) = atomic_rcu_read(&(var)->field.sqe_next), 1); \

         (var) = (next))



/*

 * RCU tail queue

 */



/* Tail queue access methods */

#define QTAILQ_EMPTY_RCU(head)      (atomic_read(&(head)->tqh_first) == NULL)

#define QTAILQ_FIRST_RCU(head)       atomic_rcu_read(&(head)->tqh_first)

#define QTAILQ_NEXT_RCU(elm, field)  atomic_rcu_read(&(elm)->field.tqe_next)



/* Tail queue functions */

#define QTAILQ_INSERT_HEAD_RCU(head, elm, field) do {                   \

    (elm)->field.tqe_next = (head)->tqh_first;                          \

    if ((elm)->field.tqe_next != NULL) {                                \

        (head)->tqh_first->field.tqe_prev = &(elm)->field.tqe_next;     \

    } else {                                                            \

        (head)->tqh_last = &(elm)->field.tqe_next;                      \

    }                                                                   \

    atomic_rcu_set(&(head)->tqh_first, (elm));                          \

    (elm)->field.tqe_prev = &(head)->tqh_first;                         \

} while (/*CONSTCOND*/0)



#define QTAILQ_INSERT_TAIL_RCU(head, elm, field) do {               \

    (elm)->field.tqe_next = NULL;                                   \

    (elm)->field.tqe_prev = (head)->tqh_last;                       \

    atomic_rcu_set((head)->tqh_last, (elm));                        \

    (head)->tqh_last = &(elm)->field.tqe_next;                      \

} while (/*CONSTCOND*/0)



#define QTAILQ_INSERT_AFTER_RCU(head, listelm, elm, field) do {         \

    (elm)->field.tqe_next = (listelm)->field.tqe_next;                  \

    if ((elm)->field.tqe_next != NULL) {                                \

        (elm)->field.tqe_next->field.tqe_prev = &(elm)->field.tqe_next; \

    } else {                                                            \

        (head)->tqh_last = &(elm)->field.tqe_next;                      \

    }                                                                   \

    atomic_rcu_set(&(listelm)->field.tqe_next, (elm));                  \

    (elm)->field.tqe_prev = &(listelm)->field.tqe_next;                 \

} while (/*CONSTCOND*/0)



#define QTAILQ_INSERT_BEFORE_RCU(listelm, elm, field) do {          \

    (elm)->field.tqe_prev = (listelm)->field.tqe_prev;              \

    (elm)->field.tqe_next = (listelm);                              \

    atomic_rcu_set((listelm)->field.tqe_prev, (elm));               \

    (listelm)->field.tqe_prev = &(elm)->field.tqe_next;             \

    } while (/*CONSTCOND*/0)



#define QTAILQ_REMOVE_RCU(head, elm, field) do {                        \

    if (((elm)->field.tqe_next) != NULL) {                              \

        (elm)->field.tqe_next->field.tqe_prev = (elm)->field.tqe_prev;  \

    } else {                                                            \

        (head)->tqh_last = (elm)->field.tqe_prev;                       \

    }                                                                   \

    atomic_set((elm)->field.tqe_prev, (elm)->field.tqe_next);           \

    (elm)->field.tqe_prev = NULL;                                       \

} while (/*CONSTCOND*/0)



#define QTAILQ_FOREACH_RCU(var, head, field)                            \

    for ((var) = atomic_rcu_read(&(head)->tqh_first);                   \

         (var);                                                         \

         (var) = atomic_rcu_read(&(var)->field.tqe_next))



#define QTAILQ_FOREACH_SAFE_RCU(var, head, field, next)                  \

    for ((var) = atomic_rcu_read(&(head)->tqh_first);                    \

         (var) && ((next) = atomic_rcu_read(&(var)->field.tqe_next), 1); \

         (var) = (next))



#ifdef __cplusplus

}

#endif