[ovs-dev] [PATCH v8 07/13] dp-packet: Handle multi-seg mbufs in put*() funcs.

Tiago Lam tiago.lam at intel.com
Mon Jun 11 16:21:23 UTC 2018


The dp_packet_put*() function - dp_packet_put_uninit(), dp_packet_put()
and dp_packet_put_zeros() - are, in their current implementation,
operating on the data buffer of a dp_packet as if it were contiguous,
which in the case of multi-segment mbufs means they operate on the first
mbuf in the chain. However, in the case of dp_packet_put_uninit(), for
example, it is the data length of the last mbuf in the mbuf chain that
should be adjusted. These functions have thus been modified to support
multi-segment mbufs.

Additionally, most of the core logic in dp_pcket_put_uninit() was moved
to a new helper function, dp_packet_put_uninit()_, to abstract the
implementation details from the API, since in the case of multi-seg
mbufs a new struct is returned that holds the mbuf and offset that
constitute the tail. For the single mbuf case a pointer to the byte that
constitute the tail still returned.

Co-authored-by: Mark Kavanagh <mark.b.kavanagh at intel.com>

Signed-off-by: Mark Kavanagh <mark.b.kavanagh at intel.com>
Signed-off-by: Tiago Lam <tiago.lam at intel.com>
---
 lib/dp-packet.c | 34 ++++++++++++++++++++++++----------
 lib/dp-packet.h |  5 +++++
 2 files changed, 29 insertions(+), 10 deletions(-)

diff --git a/lib/dp-packet.c b/lib/dp-packet.c
index 2aaeaae..9b97dd4 100644
--- a/lib/dp-packet.c
+++ b/lib/dp-packet.c
@@ -321,29 +321,43 @@ dp_packet_put_uninit(struct dp_packet *b, size_t size)
     void *p;
     dp_packet_prealloc_tailroom(b, size);
     p = dp_packet_tail(b);
+#ifdef DPDK_NETDEV
+    struct rte_mbuf *mbuf;
+
+    if (b->source == DPBUF_DPDK) {
+        mbuf = rte_pktmbuf_lastseg(&b->mbuf);
+    } else {
+        mbuf = CONST_CAST(struct rte_mbuf *, &b->mbuf);
+    }
+
+    mbuf->data_len += size;
+#endif
     dp_packet_set_size(b, dp_packet_size(b) + size);
+
     return p;
 }
 
-/* Appends 'size' zeroed bytes to the tail end of 'b'.  Data in 'b' is
- * reallocated and copied if necessary.  Returns a pointer to the first byte of
- * the data's location in the dp_packet. */
+/* Appends the 'size' bytes of data in 'p' to the tail end of 'b'.  Data in 'b'
+ * is reallocated and copied if necessary.  Returns a pointer to the first
+ * byte of the data's location in the dp_packet. */
 void *
-dp_packet_put_zeros(struct dp_packet *b, size_t size)
+dp_packet_put(struct dp_packet *b, const void *p, size_t size)
 {
     void *dst = dp_packet_put_uninit(b, size);
-    memset(dst, 0, size);
+    memcpy(dst, p, size);
+
     return dst;
 }
 
-/* Appends the 'size' bytes of data in 'p' to the tail end of 'b'.  Data in 'b'
- * is reallocated and copied if necessary.  Returns a pointer to the first
- * byte of the data's location in the dp_packet. */
+/* Appends 'size' zeroed bytes to the tail end of 'b'.  Data in 'b' is
+ * reallocated and copied if necessary.  Returns a pointer to the first byte of
+ * the data's location in the dp_packet. */
 void *
-dp_packet_put(struct dp_packet *b, const void *p, size_t size)
+dp_packet_put_zeros(struct dp_packet *b, size_t size)
 {
     void *dst = dp_packet_put_uninit(b, size);
-    memcpy(dst, p, size);
+    memset(dst, 0, size);
+
     return dst;
 }
 
diff --git a/lib/dp-packet.h b/lib/dp-packet.h
index 21fa05e..8c0e23c 100644
--- a/lib/dp-packet.h
+++ b/lib/dp-packet.h
@@ -83,6 +83,11 @@ struct dp_packet {
 #ifdef DPDK_NETDEV
 #define MBUF_BUF_END(BUF_ADDR, BUF_LEN) \
     (char *) (((char *) BUF_ADDR) + BUF_LEN)
+
+struct mbuf_tail {
+    struct rte_mbuf *mbuf;
+    uint16_t ofs;
+};
 #endif
 
 static inline void *dp_packet_data(const struct dp_packet *);
-- 
2.7.4



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