Simon Schippers wrote: > Add __ptr_ring_consume_created_space() to check whether the previous > __ptr_ring_consume() call successfully consumed an element and created > space in the ring buffer. This enables callers to conditionally notify > producers when space becomes available. > > The function is only valid immediately after a single consume operation > and should not be used after calling __ptr_ring_consume_batched().
Please explain why it is only valid in that case. > Co-developed-by: Tim Gebauer <[email protected]> > Signed-off-by: Tim Gebauer <[email protected]> > Co-developed by: Jon Kohler <[email protected]> > Signed-off-by: Jon Kohler <[email protected]> > Signed-off-by: Simon Schippers <[email protected]> > --- > include/linux/ptr_ring.h | 17 +++++++++++++++++ > 1 file changed, 17 insertions(+) > > diff --git a/include/linux/ptr_ring.h b/include/linux/ptr_ring.h > index da141cc8b075..76d6840b45a3 100644 > --- a/include/linux/ptr_ring.h > +++ b/include/linux/ptr_ring.h > @@ -453,6 +453,23 @@ static inline int ptr_ring_consume_batched_bh(struct > ptr_ring *r, > return ret; > } > > +/* > + * Check if the previous consume operation created space > + * > + * Returns true if the last call to __ptr_ring_consume() has created > + * space in the ring buffer (i.e., an element was consumed). > + * > + * Note: This function is only valid immediately after a single call to > + * __ptr_ring_consume(). If multiple calls to ptr_ring_consume*() have > + * been made, this check must be performed after each call individually. > + * Likewise, do not use this function after calling > + * __ptr_ring_consume_batched(). > + */ > +static inline bool __ptr_ring_consume_created_space(struct ptr_ring *r) > +{ > + return r->consumer_tail >= r->consumer_head; > +} > + > /* Cast to structure type and call a function without discarding from FIFO. > * Function must return a value. > * Callers must take consumer_lock. > -- > 2.43.0 >
