[PATCH] net/nfp: fix mbufs releasing when stop or close

[PATCH] net/nfp: fix mbufs releasing when stop or close

[Alejandro Lucero]

PMDs have the responsabilty of releasing mbufs sent through xmit burst
function. NFP PMD attaches those sent mbufs to the TX ring structure,
and it is at the next time a specific ring descriptor is going to be
used when the previous linked mbuf, already transmitted at that point,
is released. Those mbufs belonging to a chained mbuf got its own link
to a ring descriptor, and they are released independently of the mbuf
head of that chain.

The problem is how those mbufs are released when the PMD is stopped or
closed. Instead of releasing those mbufs as the xmit functions does,
this is independently of being in a mbuf chain, the code calls
rte_pktmbuf_free which will release not just the mbuf head in that
chain but all the chained mbufs. The loop will try to release those
mbufs which have already been released again when chained mbufs exist.

This patch fixes the problem using rte_pktmbuf_free_seg instead.

Fixes: b812daadad0d ("nfp: add Rx and Tx")

Signed-off-by: Alejandro Lucero <alejandro.lucero@netronome.com>
---
 drivers/net/nfp/nfp_net.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/net/nfp/nfp_net.c b/drivers/net/nfp/nfp_net.c
index 2a4b006..a5875f2 100644
--- a/drivers/net/nfp/nfp_net.c
+++ b/drivers/net/nfp/nfp_net.c
@@ -263,7 +263,7 @@ enum nfp_qcp_ptr {
 
 	for (i = 0; i < txq->tx_count; i++) {
 		if (txq->txbufs[i].mbuf) {
-			rte_pktmbuf_free(txq->txbufs[i].mbuf);
+			rte_pktmbuf_free_seg(txq->txbufs[i].mbuf);
 			txq->txbufs[i].mbuf = NULL;
 		}
 	}
-- 
1.9.1

Re: [dpdk-stable] [PATCH] net/nfp: fix mbufs releasing when stop or close

[Ferruh Yigit]

On 4/23/2018 12:23 PM, Alejandro Lucero wrote:
> PMDs have the responsabilty of releasing mbufs sent through xmit burst
> function. NFP PMD attaches those sent mbufs to the TX ring structure,
> and it is at the next time a specific ring descriptor is going to be
> used when the previous linked mbuf, already transmitted at that point,
> is released. Those mbufs belonging to a chained mbuf got its own link
> to a ring descriptor, and they are released independently of the mbuf
> head of that chain.
> 
> The problem is how those mbufs are released when the PMD is stopped or
> closed. Instead of releasing those mbufs as the xmit functions does,
> this is independently of being in a mbuf chain, the code calls
> rte_pktmbuf_free which will release not just the mbuf head in that
> chain but all the chained mbufs. The loop will try to release those
> mbufs which have already been released again when chained mbufs exist.
> 
> This patch fixes the problem using rte_pktmbuf_free_seg instead.
> 
> Fixes: b812daadad0d ("nfp: add Rx and Tx")
> 
> Signed-off-by: Alejandro Lucero <alejandro.lucero@netronome.com>

Applied to dpdk-next-net/master, thanks.