When a dp_packet is from a DPDK source, and it contains multi-segment
mbufs, the data_len is not equal to the packet size, pkt_len. Instead,
the data_len of each mbuf in the chain should be considered while
distributing the new (provided) size.
To account for the above dp_packet_set_size() has been changed so that,
in the multi-segment mbufs case, only the data_len on the last mbuf of
the chain and the total size of the packet, pkt_len, are changed. The
data_len on the intermediate mbufs preceeding the last mbuf is not
changed by dp_packet_set_size(). Furthermore, in some cases
dp_packet_set_size() may be used to set a smaller size than the current
packet size, thus effectively trimming the end of the packet. In the
multi-segment mbufs case this may lead to lingering mbufs that may need
freeing.
__dp_packet_set_data() now also updates an mbufs' data_len after setting
the data offset. This is so that both fields are always in sync for each
mbuf in a chain.
Co-authored-by: Michael Qiu <qiud...@chinac.com>
Co-authored-by: Mark Kavanagh <mark.b.kavan...@intel.com>
Co-authored-by: Przemyslaw Lal <przemyslawx....@intel.com>
Co-authored-by: Marcin Ksiadz <mksi...@gmail.com>
Co-authored-by: Yuanhan Liu <y...@fridaylinux.org>
Signed-off-by: Michael Qiu <qiud...@chinac.com>
Signed-off-by: Mark Kavanagh <mark.b.kavan...@intel.com>
Signed-off-by: Przemyslaw Lal <przemyslawx....@intel.com>
Signed-off-by: Marcin Ksiadz <mksi...@gmail.com>
Signed-off-by: Yuanhan Liu <y...@fridaylinux.org>
Signed-off-by: Tiago Lam <tiago....@intel.com>
---
lib/dp-packet.h | 38 +++++++++++++++++++++++++++-----------
1 file changed, 27 insertions(+), 11 deletions(-)
diff --git a/lib/dp-packet.h b/lib/dp-packet.h
index d6512cf..93b0aaf 100644
--- a/lib/dp-packet.h
+++ b/lib/dp-packet.h
@@ -397,17 +397,31 @@ dp_packet_size(const struct dp_packet *b)
static inline void
dp_packet_set_size(struct dp_packet *b, uint32_t v)
{
- /* netdev-dpdk does not currently support segmentation; consequently, for
- * all intents and purposes, 'data_len' (16 bit) and 'pkt_len' (32 bit) may
- * be used interchangably.
- *
- * On the datapath, it is expected that the size of packets
- * (and thus 'v') will always be <= UINT16_MAX; this means that there is no
- * loss of accuracy in assigning 'v' to 'data_len'.
- */
- b->mbuf.data_len = (uint16_t)v; /* Current seg length. */
- b->mbuf.pkt_len = v; /* Total length of all segments linked to
- * this segment. */
+ if (b->source == DPBUF_DPDK) {
+ struct rte_mbuf *seg = &b->mbuf;
+ uint16_t pkt_len = v;
+ uint16_t seg_len;
+
+ /* Trim 'v' length bytes from the end of the chained buffers, freeing
+ any buffers that may be left floating */
+ while (seg) {
+ seg_len = MIN(pkt_len, seg->data_len);
+ seg->data_len = seg_len;
+
+ pkt_len -= seg_len;
+ if (pkt_len <= 0) {
+ /* Free the rest of chained mbufs */
+ rte_pktmbuf_free(seg->next);
+ seg->next = NULL;
+ }
+ seg = seg->next;
+ }
+ } else {
+ b->mbuf.data_len = v;
+ }
+
+ /* Total length of all segments linked to this segment. */
+ b->mbuf.pkt_len = v;
}
static inline uint16_t
@@ -420,6 +434,8 @@ static inline void
__packet_set_data(struct dp_packet *b, uint16_t v)
{
b->mbuf.data_off = v;
+ /* When dealing with DPDK mbufs, keep data_off and data_len in sync */
+ b->mbuf.data_len = b->mbuf.buf_len - b->mbuf.data_off;
}
static inline void *
--
2.7.4
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