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Make sure returned value is checked and assert a valid refcount.

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While at it fix a print: Unsigned types cannot be negative.

Reviewed by:		kib, mjg
Differential revision:	https://reviews.freebsd.org/D17616
MFC after:		1 week
Sponsored by:		Mellanox Technologies
This commit is contained in:
hselasky 2018-10-22 16:21:50 +00:00
parent 786751e464
commit 782d004253
1 changed files with 8 additions and 3 deletions
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11
sys/sys/refcount.h
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@ -62,7 +62,7 @@ refcount_release(volatile u_int *count)
atomic_thread_fence_rel(); atomic_thread_fence_rel();
old = atomic_fetchadd_int(count, -1); old = atomic_fetchadd_int(count, -1);
KASSERT(old > 0, ("negative refcount %p", count)); KASSERT(old > 0, ("refcount %p is zero", count));
if (old > 1) if (old > 1)
return (0); return (0);
@ -77,15 +77,19 @@ refcount_release(volatile u_int *count)
} }
/* /*
* This functions returns non-zero if the refcount was
* incremented. Else zero is returned.
*
* A temporary hack until refcount_* APIs are sorted out. * A temporary hack until refcount_* APIs are sorted out.
*/ */
static __inline int static __inline __result_use_check int
refcount_acquire_if_not_zero(volatile u_int *count) refcount_acquire_if_not_zero(volatile u_int *count)
{ {
u_int old; u_int old;
old = *count; old = *count;
for (;;) { for (;;) {
KASSERT(old < UINT_MAX, ("refcount %p overflowed", count));
if (old == 0) if (old == 0)
return (0); return (0);
if (atomic_fcmpset_int(count, &old, old + 1)) if (atomic_fcmpset_int(count, &old, old + 1))
@ -93,13 +97,14 @@ refcount_acquire_if_not_zero(volatile u_int *count)
} }
} }
static __inline int static __inline __result_use_check int
refcount_release_if_not_last(volatile u_int *count) refcount_release_if_not_last(volatile u_int *count)
{ {
u_int old; u_int old;
old = *count; old = *count;
for (;;) { for (;;) {
KASSERT(old > 0, ("refcount %p is zero", count));
if (old == 1) if (old == 1)
return (0); return (0);
if (atomic_fcmpset_int(count, &old, old - 1)) if (atomic_fcmpset_int(count, &old, old - 1))