[ovs-dev] [PATCH 3/5] lib/dp-packet: Fix data_len issue with multi-segments

[Kavanagh, Mark B]

>
This patch didn't apply cleanly either; 'apply -3' resolved the issue, but I recommend rebasing to HEAD of master for next version.

Other than that, just some minor cosmetic comments inline.

>When a packet is from DPDK source, and it contains
>multipule segments, data_len is not equal to the

Typo in the previous line - 'multipule'

>packet size. This patch fix this issue.
>
>Signed-off-by: Michael Qiu <qiudayu at chinac.com>
>Signed-off-by: Marcin Ksiadz <marcinx.ksiadz at intel.com>
>Signed-off-by: Mark Kavanagh <mark.b.kavanagh at intel.com>
>Signed-off-by: Przemyslaw Lal <przemyslawx.lal at intel.com>
>Signed-off-by: Yuanhan Liu <yuanhan.liu at linux.intel.com>
>---
> lib/dp-packet.h | 27 +++++++++++++++++----------
> 1 file changed, 17 insertions(+), 10 deletions(-)
>
>diff --git a/lib/dp-packet.h b/lib/dp-packet.h
>index 7c1e637..b5a55bb 100644
>--- a/lib/dp-packet.h
>+++ b/lib/dp-packet.h
>@@ -24,6 +24,10 @@
> #include "util.h"
> #include "netdev-dpdk.h"
>
>+#ifdef DPDK_NETDEV
>+#include "rte_ether.h"
>+#endif
>+
> #ifdef  __cplusplus
> extern "C" {
> #endif
>@@ -409,17 +413,20 @@ 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'.
>+    /*
>+     * Assign current segment length. If total length is greater than
>+     * max data length in a segment, additional calculation is needed
>      */
>-    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 (v > (b->mbuf.buf_len - b->mbuf.data_off)) {
>+        b->mbuf.data_len =
>+            (uint16_t)(b->mbuf.buf_len - b->mbuf.data_off);

Coding style: there should be a space between cast type and attribute being cast (this mistake was present in the previous code, to be fair).

>+    } else {
>+        b->mbuf.data_len = (uint16_t)v;

As above.

>+    }
>+
>+    /* Total length of all segments linked to
>+     * this segment. */

It might be clearer to phrase it along the lines of 'Total length of all packet segments'; also, with its current length, this comment can fit on one line.

>+    b->mbuf.pkt_len = v;
> }
>
> static inline uint16_t
>--
>1.8.3.1