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Commit 728fc8d5 authored by Jason Wang's avatar Jason Wang Committed by David S. Miller
Browse files

ptr_ring: introduce batch dequeuing 



This patch introduce a batched version of consuming, consumer can
dequeue more than one pointers from the ring at a time. We don't care
about the reorder of reading here so no need for compiler barrier.

Signed-off-by: default avatarJason Wang <jasowang@redhat.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 3acb6960

include/linux/ptr_ring.h

+65 −0
Original line number Diff line number Diff line
@@ -278,6 +278,22 @@ 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;



	for (i = 0; i < n; i++) {

		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
@@ -328,6 +344,55 @@ 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.