To change the definition of (atomic_)cmpxchg. This patch is for code review
only.
Before the patch:
old/(old+1) (atomic_)cmpxchg(*ptr, old, new)
After the patch:
true/false (atomic_)cmpxchg(*ptr, *old, new)
Signed-off-by: Junchang@T470s <junchangwang@xxxxxxxxx>
---
CodeSamples/advsync/q.c | 2 +-
CodeSamples/advsync/singleq.c | 3 ++-
CodeSamples/api-pthreads/api-gcc.h | 12 ++++--------
CodeSamples/count/count_lim_atomic.c | 8 ++++----
CodeSamples/defer/rcu64_atomicgp.c | 2 +-
CodeSamples/defer/route_refcnt.c | 2 +-
6 files changed, 13 insertions(+), 16 deletions(-)
diff --git a/CodeSamples/advsync/q.c b/CodeSamples/advsync/q.c
index 5fade3e..4e8abd3 100644
--- a/CodeSamples/advsync/q.c
+++ b/CodeSamples/advsync/q.c
@@ -51,7 +51,7 @@ struct el *q_pop(struct queue *q)
pnext = p->next;
if (pnext == NULL)
return NULL;
- } while (cmpxchg(&q->head, p, pnext) != p);
+ } while (!cmpxchg(&q->head, &p, pnext));
if (p != &q->dummy)
return p;
q_push(&q->dummy, q);
diff --git a/CodeSamples/advsync/singleq.c b/CodeSamples/advsync/singleq.c
index 6586561..c56c8d8 100644
--- a/CodeSamples/advsync/singleq.c
+++ b/CodeSamples/advsync/singleq.c
@@ -31,7 +31,8 @@ void init_q(struct queue *qp)
int q_push(struct el *ep, struct queue *qp)
{
- return cmpxchg(&qp->head, NULL, ep) == NULL;
+ void *nil = NULL;
+ return cmpxchg(&qp->head, &nil, ep);
}
struct el *q_pop(struct queue *qp)
diff --git a/CodeSamples/api-pthreads/api-gcc.h b/CodeSamples/api-pthreads/api-gcc.h
index 3afe340..9cb5998 100644
--- a/CodeSamples/api-pthreads/api-gcc.h
+++ b/CodeSamples/api-pthreads/api-gcc.h
@@ -166,13 +166,11 @@ struct __xchg_dummy {
#define cmpxchg(ptr, o, n) \
({ \
- typeof(*ptr) _____actual = (o); \
- \
- __atomic_compare_exchange_n(ptr, (void *)&_____actual, (n), 1, \
- __ATOMIC_SEQ_CST, __ATOMIC_SEQ_CST) ? (o) : (o)+1; \
+ __atomic_compare_exchange_n(ptr, (void *)(o), (n), 1, \
+ __ATOMIC_SEQ_CST, __ATOMIC_SEQ_CST); \
})
-static __inline__ int atomic_cmpxchg(atomic_t *v, int old, int new)
+static __inline__ int atomic_cmpxchg(atomic_t *v, int *old, int new)
{
return cmpxchg(&v->counter, old, new);
}
@@ -197,10 +195,8 @@ static __inline__ int atomic_cmpxchg(atomic_t *v, int old, int new)
for (;;) { \
if (unlikely(c == (u))) \
break; \
- old = atomic_cmpxchg((v), c, c + (a)); \
- if (likely(old == c)) \
+ if (likely(atomic_cmpxchg((v), &c, c + (a)))) \
break; \
- c = old; \
} \
c != (u); \
})
diff --git a/CodeSamples/count/count_lim_atomic.c b/CodeSamples/count/count_lim_atomic.c
index 02f4e6d..72bdb65 100644
--- a/CodeSamples/count/count_lim_atomic.c
+++ b/CodeSamples/count/count_lim_atomic.c
@@ -106,8 +106,8 @@ int add_count(unsigned long delta) //\lnlbl{add:b}
if (delta > MAX_COUNTERMAX || c + delta > cm)//\lnlbl{add:check}
goto slowpath; //\lnlbl{add:goto}
new = merge_counterandmax(c + delta, cm);//\lnlbl{add:merge}
- } while (atomic_cmpxchg(&counterandmax, //\lnlbl{add:atmcmpex}
- old, new) != old); //\lnlbl{add:loop:e}
+ } while (!atomic_cmpxchg(&counterandmax, //\lnlbl{add:atmcmpex}
+ &old, new)); //\lnlbl{add:loop:e}
return 1; //\lnlbl{add:return:fs}
slowpath: //\lnlbl{add:slow:b}
spin_lock(&gblcnt_mutex); //\lnlbl{add:acquire}
@@ -139,8 +139,8 @@ int sub_count(unsigned long delta) //\lnlbl{sub:b}
if (delta > c)
goto slowpath;
new = merge_counterandmax(c - delta, cm);
- } while (atomic_cmpxchg(&counterandmax,
- old, new) != old);
+ } while (!atomic_cmpxchg(&counterandmax,
+ &old, new));
return 1; //\lnlbl{sub:fast:e}
slowpath: //\lnlbl{sub:slow:b}
spin_lock(&gblcnt_mutex);
diff --git a/CodeSamples/defer/rcu64_atomicgp.c b/CodeSamples/defer/rcu64_atomicgp.c
index f7cb6ff..923df93 100644
--- a/CodeSamples/defer/rcu64_atomicgp.c
+++ b/CodeSamples/defer/rcu64_atomicgp.c
@@ -39,7 +39,7 @@ void synchronize_rcu(void)
*/
oldval = rcu_gp_ctr;
- (void)cmpxchg(&rcu_gp_ctr, oldval, oldval - 1);
+ (void)cmpxchg(&rcu_gp_ctr, &oldval, oldval - 1);
smp_mb();
/*
diff --git a/CodeSamples/defer/route_refcnt.c b/CodeSamples/defer/route_refcnt.c
index 8a48faf..c202548 100644
--- a/CodeSamples/defer/route_refcnt.c
+++ b/CodeSamples/defer/route_refcnt.c
@@ -68,7 +68,7 @@ retry:
if (old <= 0)
goto retry;
new = old + 1;
- } while (atomic_cmpxchg(&rep->re_refcnt, old, new) != old);
+ } while (!atomic_cmpxchg(&rep->re_refcnt, &old, new));
/* Advance to next. */
repp = &rep->re_next;
--
2.7.4
