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Surround reference count decrement-branch by release/acquire membars. #127

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Surround reference count decrement-branch by release/acquire membars. #127

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2 changes: 2 additions & 0 deletions src/kern/npf_nat.c
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Original file line number Diff line number Diff line change
Expand Up @@ -257,9 +257,11 @@ npf_natpolicy_release(npf_natpolicy_t *np)
{
KASSERT(atomic_load_relaxed(&np->n_refcnt) > 0);

membar_release();
if (atomic_dec_uint_nv(&np->n_refcnt) != 0) {
return;
}
membar_acquire();
KASSERT(LIST_EMPTY(&np->n_nat_list));
mutex_destroy(&np->n_lock);
kmem_free(np, sizeof(npf_natpolicy_t));
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2 changes: 2 additions & 0 deletions src/kern/npf_rproc.c
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Expand Up @@ -308,9 +308,11 @@ npf_rproc_release(npf_rproc_t *rp)
{
KASSERT(atomic_load_relaxed(&rp->rp_refcnt) > 0);

membar_release();
if (atomic_dec_uint_nv(&rp->rp_refcnt) != 0) {
return;
}
membar_acquire();
/* XXXintr */
for (unsigned i = 0; i < rp->rp_ext_count; i++) {
npf_ext_t *ext = rp->rp_ext[i];
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10 changes: 7 additions & 3 deletions src/kern/npf_tableset.c
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Expand Up @@ -136,9 +136,13 @@ npf_tableset_destroy(npf_tableset_t *ts)
for (u_int tid = 0; tid < ts->ts_nitems; tid++) {
npf_table_t *t = ts->ts_map[tid];

if (t && atomic_dec_uint_nv(&t->t_refcnt) == 0) {
npf_table_destroy(t);
}
if (t == NULL)
continue;
membar_release();
if (atomic_dec_uint_nv(&t->t_refcnt) > 0)
continue;
membar_acquire();
npf_table_destroy(t);
}
kmem_free(ts, NPF_TABLESET_SIZE(ts->ts_nitems));
}
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2 changes: 2 additions & 0 deletions src/kern/stand/npf_stand.h
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Expand Up @@ -136,6 +136,8 @@ npfkern_atomic_swap_ptr(volatile void *ptr, void *newval)
#define membar_sync() __sync_synchronize()
#define membar_consumer() __sync_synchronize()
#define membar_producer() __sync_synchronize()
#define membar_release() __sync_synchronize()
#define membar_acquire() __sync_synchronize()
#define atomic_inc_uint(x) __sync_fetch_and_add((x), 1)
#define atomic_inc_uint_nv(x) __sync_add_and_fetch((x), 1)
#define atomic_inc_ulong_nv(x) __sync_add_and_fetch((x), 1)
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