[dpdk-dev] [PATCH v2 1/5] mbuf: ensure next pointer is set to null on free

[Bruce Richardson]

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

Changes in V2:
* None

Signed-off-by: Bruce Richardson <bruce.richardson at 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