[1/3] reorder: add new drain up to seq number API

diff --git a/lib/reorder/rte_reorder.c b/lib/reorder/rte_reorder.c
index 385ee479da..57cc1b286b 100644
--- a/lib/reorder/rte_reorder.c
+++ b/lib/reorder/rte_reorder.c
@@ -406,3 +406,80 @@  rte_reorder_drain(struct rte_reorder_buffer *b, struct rte_mbuf **mbufs,
 
 	return drain_cnt;
 }
+
+/* Binary search seqn in ready buffer */
+static inline uint32_t
+ready_buffer_seqn_find(const struct cir_buffer *ready_buf, const uint32_t seqn)
+{
+	uint32_t mid, value, position, high;
+	uint32_t low = 0;
+
+	if (ready_buf->tail > ready_buf->head)
+		high = ready_buf->tail - ready_buf->head;
+	else
+		high = ready_buf->head - ready_buf->tail;
+
+	while (low <= high) {
+		mid = low + (high - low) / 2;
+		position = (ready_buf->tail + mid) & ready_buf->mask;
+		value = *rte_reorder_seqn(ready_buf->entries[position]);
+		if (seqn == value)
+			return mid;
+		else if (seqn > value)
+			low = mid + 1;
+		else
+			high = mid - 1;
+	}
+
+	return low;
+}
+
+unsigned int
+rte_reorder_drain_up_to_seqn(struct rte_reorder_buffer *b, struct rte_mbuf **mbufs,
+		const unsigned int max_mbufs, const rte_reorder_seqn_t seqn)
+{
+	uint32_t i, position, offset;
+	unsigned int drain_cnt = 0;
+
+	struct cir_buffer *order_buf = &b->order_buf,
+			*ready_buf = &b->ready_buf;
+
+	/* Seqn in Ready buffer */
+	if (seqn < b->min_seqn) {
+		/* All sequence numbers are higher then given */
+		if (*rte_reorder_seqn(ready_buf->entries[ready_buf->tail]) > seqn)
+			return 0;
+
+		offset = ready_buffer_seqn_find(ready_buf, seqn);
+
+		for (i = 0; (i < offset) && (drain_cnt < max_mbufs); i++) {
+			position = (ready_buf->tail + i) & ready_buf->mask;
+			mbufs[drain_cnt++] = ready_buf->entries[position];
+			ready_buf->entries[position] = NULL;
+		}
+		ready_buf->tail = (ready_buf->tail + i) & ready_buf->mask;
+
+		return drain_cnt;
+	}
+
+	/* Seqn in Order buffer, add all buffers from Ready buffer */
+	while ((drain_cnt < max_mbufs) && (ready_buf->tail != ready_buf->head)) {
+		mbufs[drain_cnt++] = ready_buf->entries[ready_buf->tail];
+		ready_buf->entries[ready_buf->tail] = NULL;
+		ready_buf->tail = (ready_buf->tail + 1) & ready_buf->mask;
+	}
+
+	/* Fetch buffers from Order buffer up to given sequence number (exclusive) */
+	offset = RTE_MIN(seqn - b->min_seqn, b->order_buf.size);
+	for (i = 0; (i < offset) && (drain_cnt < max_mbufs); i++) {
+		position = (order_buf->head + i) & order_buf->mask;
+		if (order_buf->entries[position] == NULL)
+			continue;
+		mbufs[drain_cnt++] = order_buf->entries[position];
+		order_buf->entries[position] = NULL;
+	}
+	b->min_seqn += i;
+	order_buf->head = (order_buf->head + i) & order_buf->mask;
+
+	return drain_cnt;
+}
diff --git a/lib/reorder/rte_reorder.h b/lib/reorder/rte_reorder.h
index 5abdb258e2..c5b354b53d 100644
--- a/lib/reorder/rte_reorder.h
+++ b/lib/reorder/rte_reorder.h
@@ -167,6 +167,31 @@  unsigned int
 rte_reorder_drain(struct rte_reorder_buffer *b, struct rte_mbuf **mbufs,
 		unsigned max_mbufs);
 
+/**
+ * @warning
+ * @b EXPERIMENTAL: this API may change without prior notice
+ *
+ * Fetch set of reordered packets up to specified sequence number (exclusive)
+ *
+ * Returns a set of in-order packets from the reorder buffer structure.
+ * Gaps may be present since reorder buffer will try to fetch all possible packets up to given
+ * sequence number.
+ *
+ * @param b
+ *   Reorder buffer instance from which packets are to be drained.
+ * @param mbufs
+ *   Array of mbufs where reordered packets will be inserted from reorder buffer.
+ * @param max_mbufs
+ *   The number of elements in the mbufs array.
+ * @param seqn
+ *   Sequence number up to which buffer will be drained.
+ * @return
+ *   Number of mbuf pointers written to mbufs. 0 <= N < max_mbufs.
+ */
+__rte_experimental
+unsigned int
+rte_reorder_drain_up_to_seqn(struct rte_reorder_buffer *b, struct rte_mbuf **mbufs,
+		unsigned int max_mbufs, rte_reorder_seqn_t seqn);
 #ifdef __cplusplus
 }
 #endif
diff --git a/lib/reorder/version.map b/lib/reorder/version.map
index e114d17730..e3f41ea7ef 100644
--- a/lib/reorder/version.map
+++ b/lib/reorder/version.map
@@ -16,4 +16,5 @@  EXPERIMENTAL {
 	global:
 
 	rte_reorder_seqn_dynfield_offset;
+	rte_reorder_drain_up_to_seqn;
 };