On Tue, Mar 21, 2017 at 12:04:40PM +0800, Jason Wang wrote:
> Signed-off-by: Jason Wang <jasow...@redhat.com>
> ---
> include/linux/ptr_ring.h | 65
> ++++++++++++++++++++++++++++++++++++++++++++++++
> 1 file changed, 65 insertions(+)
>
> diff --git a/include/linux/ptr_ring.h b/include/linux/ptr_ring.h
> index 6c70444..4771ded 100644
> --- a/include/linux/ptr_ring.h
> +++ b/include/linux/ptr_ring.h
> @@ -247,6 +247,22 @@ static inline void *__ptr_ring_consume(struct ptr_ring
> *r)
> return ptr;
> }
>
> +static inline int __ptr_ring_consume_batched(struct ptr_ring *r,
> + void **array, int n)
> +{
> + void *ptr;
> + int i = 0;
> +
> + while (i < n) {
> + ptr = __ptr_ring_consume(r);
> + if (!ptr)
> + break;
> + array[i++] = ptr;
> + }
> +
> + return i;
> +}
> +
> /*
> * Note: resize (below) nests producer lock within consumer lock, so if you
> * call this in interrupt or BH context, you must disable interrupts/BH when
This ignores the comment above that function:
/* Note: callers invoking this in a loop must use a compiler barrier,
* for example cpu_relax().
*/
Also - it looks like it shouldn't matter if reads are reordered but I wonder.
Thoughts? Including some reasoning about it in commit log would be nice.
> @@ -297,6 +313,55 @@ static inline void *ptr_ring_consume_bh(struct ptr_ring
> *r)
> return ptr;
> }
>
> +static inline int ptr_ring_consume_batched(struct ptr_ring *r,
> + void **array, int n)
> +{
> + int ret;
> +
> + spin_lock(&r->consumer_lock);
> + ret = __ptr_ring_consume_batched(r, array, n);
> + spin_unlock(&r->consumer_lock);
> +
> + return ret;
> +}
> +
> +static inline int ptr_ring_consume_batched_irq(struct ptr_ring *r,
> + void **array, int n)
> +{
> + int ret;
> +
> + spin_lock_irq(&r->consumer_lock);
> + ret = __ptr_ring_consume_batched(r, array, n);
> + spin_unlock_irq(&r->consumer_lock);
> +
> + return ret;
> +}
> +
> +static inline int ptr_ring_consume_batched_any(struct ptr_ring *r,
> + void **array, int n)
> +{
> + unsigned long flags;
> + int ret;
> +
> + spin_lock_irqsave(&r->consumer_lock, flags);
> + ret = __ptr_ring_consume_batched(r, array, n);
> + spin_unlock_irqrestore(&r->consumer_lock, flags);
> +
> + return ret;
> +}
> +
> +static inline int ptr_ring_consume_batched_bh(struct ptr_ring *r,
> + void **array, int n)
> +{
> + int ret;
> +
> + spin_lock_bh(&r->consumer_lock);
> + ret = __ptr_ring_consume_batched(r, array, n);
> + spin_unlock_bh(&r->consumer_lock);
> +
> + return ret;
> +}
> +
> /* Cast to structure type and call a function without discarding from FIFO.
> * Function must return a value.
> * Callers must take consumer_lock.
> --
> 2.7.4
