Commit 13d8ef7d authored by Emilio G. Cota's avatar Emilio G. Cota Committed by Paolo Bonzini
Browse files

rcu_queue: add RCU QSIMPLEQ 



Signed-off-by: default avatarEmilio G. Cota <cota@braap.org>
Message-Id: <20180819091335.22863-4-cota@braap.org>
Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
parent 735d1af6

include/qemu/rcu_queue.h

+65 −0
Original line number Diff line number Diff line
@@ -128,6 +128,71 @@ extern "C" { 
          ((next_var) = atomic_rcu_read(&(var)->field.le_next), 1);  \

           (var) = (next_var))



/*

 * RCU simple queue

 */



/* Simple queue access methods */

#define QSIMPLEQ_EMPTY_RCU(head)      (atomic_read(&(head)->sqh_first) == NULL)

#define QSIMPLEQ_FIRST_RCU(head)       atomic_rcu_read(&(head)->sqh_first)

#define QSIMPLEQ_NEXT_RCU(elm, field)  atomic_rcu_read(&(elm)->field.sqe_next)



/* Simple queue functions */

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

    (elm)->field.sqe_next = (head)->sqh_first;                  \

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

        (head)->sqh_last = &(elm)->field.sqe_next;              \

    }                                                           \

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

} while (/*CONSTCOND*/0)



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

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

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

    (head)->sqh_last = &(elm)->field.sqe_next;             \

} while (/*CONSTCOND*/0)



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

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

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

        (head)->sqh_last = &(elm)->field.sqe_next;                      \

    }                                                                   \

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

} while (/*CONSTCOND*/0)



#define QSIMPLEQ_REMOVE_HEAD_RCU(head, field) do {                     \

    atomic_set(&(head)->sqh_first, (head)->sqh_first->field.sqe_next); \

    if ((head)->sqh_first == NULL) {                                   \

        (head)->sqh_last = &(head)->sqh_first;                         \

    }                                                                  \

} while (/*CONSTCOND*/0)



#define QSIMPLEQ_REMOVE_RCU(head, elm, type, field) do {            \

    if ((head)->sqh_first == (elm)) {                               \

        QSIMPLEQ_REMOVE_HEAD_RCU((head), field);                    \

    } else {                                                        \

        struct type *curr = (head)->sqh_first;                      \

        while (curr->field.sqe_next != (elm)) {                     \

            curr = curr->field.sqe_next;                            \

        }                                                           \

        atomic_set(&curr->field.sqe_next,                           \

                   curr->field.sqe_next->field.sqe_next);           \

        if (curr->field.sqe_next == NULL) {                         \

            (head)->sqh_last = &(curr)->field.sqe_next;             \

        }                                                           \

    }                                                               \

} while (/*CONSTCOND*/0)



#define QSIMPLEQ_FOREACH_RCU(var, head, field)                          \

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

         (var);                                                         \

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



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

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

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

         (var) = (next))



#ifdef __cplusplus

}

#endif