[dpdk-dev] [PATCH 1/5] mbuf: ensure next pointer is set to null on free

[Bruce Richardson <bruce.richardson@intel.com>]

The receive functions for packets do not modify the next pointer so
the next pointer should always be cleared on mbuf free, just in case.
The slow-path TX needs to clear it, and the standard mbuf free function
also needs to clear it. Fast path TX does not handle chained mbufs so
is unaffected

Signed-off-by: Bruce Richardson <bruce.richardson@intel.com>
---
 lib/librte_mbuf/rte_mbuf.h        | 4 +++-
 lib/librte_pmd_ixgbe/ixgbe_rxtx.c | 1 +
 2 files changed, 4 insertions(+), 1 deletion(-)

diff --git a/lib/librte_mbuf/rte_mbuf.h b/lib/librte_mbuf/rte_mbuf.h
index 1c6e115..8e27d2e 100644
--- a/lib/librte_mbuf/rte_mbuf.h
+++ b/lib/librte_mbuf/rte_mbuf.h
@@ -682,8 +682,10 @@ __rte_pktmbuf_prefree_seg(struct rte_mbuf *m)
 static inline void __attribute__((always_inline))
 rte_pktmbuf_free_seg(struct rte_mbuf *m)
 {
-	if (likely(NULL != (m = __rte_pktmbuf_prefree_seg(m))))
+	if (likely(NULL != (m = __rte_pktmbuf_prefree_seg(m)))) {
+		m->next = NULL;
 		__rte_mbuf_raw_free(m);
+	}
 }
 
 /**
diff --git a/lib/librte_pmd_ixgbe/ixgbe_rxtx.c b/lib/librte_pmd_ixgbe/ixgbe_rxtx.c
index a80cade..6f702b3 100644
--- a/lib/librte_pmd_ixgbe/ixgbe_rxtx.c
+++ b/lib/librte_pmd_ixgbe/ixgbe_rxtx.c
@@ -145,6 +145,7 @@ ixgbe_tx_free_bufs(struct igb_tx_queue *txq)
 	/* free buffers one at a time */
 	if ((txq->txq_flags & (uint32_t)ETH_TXQ_FLAGS_NOREFCOUNT) != 0) {
 		for (i = 0; i < txq->tx_rs_thresh; ++i, ++txep) {
+			txep->mbuf->next = NULL;
 			rte_mempool_put(txep->mbuf->pool, txep->mbuf);
 			txep->mbuf = NULL;
 		}
-- 
1.9.3