Re: [PATCH 1/2] mbuf: Add rte_pktmbuf_copy

["Mrzyglod, DanielX T" <danielx.t.mrzyglod@intel.com>]

>-----Original Message-----
>From: dev [mailto:dev-bounces@dpdk.org] On Behalf Of Stephen Hemminger
>Sent: Friday, July 10, 2015 1:38 AM
>To: dev@dpdk.org
>Cc: Mike Davison <mdavison@brocade.com>; Stephen Hemminger
><shemming@brocade.com>
>Subject: [dpdk-dev] [PATCH 1/2] mbuf: Add rte_pktmbuf_copy
>
>From: Stephen Hemminger <shemming@brocade.com>
>
>Added rte_pktmbuf_copy() function since copying multi-part
>segments is common issue and can be problematic.
>
>Signed-off-by: Mike Davison <mdavison@brocade.com>
>Reviewed-by: Stephen Hemminger <shemming@brocade.com>
>---
> lib/librte_mbuf/rte_mbuf.h | 59
>++++++++++++++++++++++++++++++++++++++++++++++
> 1 file changed, 59 insertions(+)
>
>diff --git a/lib/librte_mbuf/rte_mbuf.h b/lib/librte_mbuf/rte_mbuf.h
>index 80419df..f0a543b 100644
>--- a/lib/librte_mbuf/rte_mbuf.h
>+++ b/lib/librte_mbuf/rte_mbuf.h
>@@ -60,6 +60,7 @@
> #include <rte_atomic.h>
> #include <rte_prefetch.h>
> #include <rte_branch_prediction.h>
>+#include <rte_memcpy.h>
>
> #ifdef __cplusplus
> extern "C" {
>@@ -1272,6 +1273,64 @@ static inline int rte_pktmbuf_is_contiguous(const
>struct rte_mbuf *m)
> 	return !!(m->nb_segs == 1);
> }
>
>+/*
>+ * Creates a copy of the given packet mbuf.
>+ *
>+ * Walks through all segments of the given packet mbuf, and for each of them:
>+ *  - Creates a new packet mbuf from the given pool.
>+ *  - Copy segment to newly created mbuf.
>+ * Then updates pkt_len and nb_segs of the new packet mbuf to match values
>+ * from the original packet mbuf.
>+ *
>+ * @param md
>+ *   The packet mbuf to be copied.
>+ * @param mp
>+ *   The mempool from which the mbufs are allocated.
>+ * @return
>+ *   - The pointer to the new mbuf on success.
>+ *   - NULL if allocation fails.
>+ */
>+static inline struct rte_mbuf *rte_pktmbuf_copy(struct rte_mbuf *md,
>+		struct rte_mempool *mp)
>+{
>+	struct rte_mbuf *mc = NULL;
>+	struct rte_mbuf **prev = &mc;
>+
>+	do {
>+		struct rte_mbuf *mi;
>+
>+		mi = rte_pktmbuf_alloc(mp);
>+		if (unlikely(mi == NULL)) {
>+			rte_pktmbuf_free(mc);
>+			return NULL;
>+		}
>+
>+		mi->data_off = md->data_off;
>+		mi->data_len = md->data_len;
>+		mi->port = md->port;
>+		mi->vlan_tci = md->vlan_tci;
>+		mi->tx_offload = md->tx_offload;
>+		mi->hash = md->hash;
>+
>+		mi->next = NULL;
>+		mi->pkt_len = md->pkt_len;
>+		mi->nb_segs = md->nb_segs;
>+		mi->ol_flags = md->ol_flags;
>+		mi->packet_type = md->packet_type;
>+
>+		rte_memcpy(rte_pktmbuf_mtod(mi, char *),
>+			   rte_pktmbuf_mtod(md, char *),
>+			   md->data_len);
>+
>+		*prev = mi;
>+		prev = &mi->next;
>+	} while ((md = md->next) != NULL);
>+
>+	*prev = NULL;
>+	__rte_mbuf_sanity_check(mc, 1);
>+	return mc;
>+}
>+
> /**
>  * Dump an mbuf structure to the console.
>  *
>--
>2.1.4

Hi Stephen :>
This patch look useful in case of backup buffs. 
There will be second approach ?