diff options
Diffstat (limited to 'include/linux/ptr_ring.h')
| -rw-r--r-- | include/linux/ptr_ring.h | 14 |
1 files changed, 10 insertions, 4 deletions
diff --git a/include/linux/ptr_ring.h b/include/linux/ptr_ring.h index c95e891903f0..631c43fde440 100644 --- a/include/linux/ptr_ring.h +++ b/include/linux/ptr_ring.h @@ -96,7 +96,13 @@ static inline bool ptr_ring_full_bh(struct ptr_ring *r) return ret; } -/* Note: callers invoking this in a loop must use a compiler barrier, +/* Report whether the next __ptr_ring_produce() has room for one entry: + * 0 means the single slot at r->queue[r->producer] is free, -ENOSPC means + * the ring is full, which is transient, and -EINVAL means r->size is 0, + * which is permanent. A caller that stops producing and waits for space + * must therefore do so only for -ENOSPC. + * + * Note: callers invoking this in a loop must use a compiler barrier, * for example cpu_relax(). Callers must hold producer_lock. */ static inline int __ptr_ring_check_produce(struct ptr_ring *r) @@ -117,10 +123,10 @@ static inline int __ptr_ring_check_produce(struct ptr_ring *r) */ static inline int __ptr_ring_produce(struct ptr_ring *r, void *ptr) { - int p = __ptr_ring_check_produce(r); + int ret = __ptr_ring_check_produce(r); - if (p) - return p; + if (ret) + return ret; /* Make sure the pointer we are storing points to a valid data. */ /* Pairs with the dependency ordering in __ptr_ring_consume. */ |