[dpdk-dev] [PATCH] net/sfc: fix double-free in EF10 ESSB Rx queue purge

[Andrew Rybchenko]

Number of buffers left in completed descriptor may be 0. If so,
all buffers of the descriptor are freed once again.

Fixes: 390f9b8d82c9 ("net/sfc: support equal stride super-buffer Rx mode")
Cc: sta...@dpdk.org

Signed-off-by: Andrew Rybchenko <arybche...@solarflare.com>
Reviewed-by: Ivan Malov <ivan.ma...@oktetlabs.ru>
---
 drivers/net/sfc/sfc_ef10_essb_rx.c | 21 ++++++---------------
 1 file changed, 6 insertions(+), 15 deletions(-)

diff --git a/drivers/net/sfc/sfc_ef10_essb_rx.c 
b/drivers/net/sfc/sfc_ef10_essb_rx.c
index 5f5af602c..dcb5cb24c 100644
--- a/drivers/net/sfc/sfc_ef10_essb_rx.c
+++ b/drivers/net/sfc/sfc_ef10_essb_rx.c
@@ -647,29 +647,20 @@ static void
 sfc_ef10_essb_rx_qpurge(struct sfc_dp_rxq *dp_rxq)
 {
        struct sfc_ef10_essb_rxq *rxq = sfc_ef10_essb_rxq_by_dp_rxq(dp_rxq);
-       unsigned int i, j;
+       unsigned int i;
        const struct sfc_ef10_essb_rx_sw_desc *rxd;
        struct rte_mbuf *m;
 
-       if (rxq->completed != rxq->added && rxq->left_in_completed > 0) {
-               rxd = &rxq->sw_ring[rxq->completed & rxq->rxq_ptr_mask];
-               m = sfc_ef10_essb_mbuf_by_index(rxq, rxd->first_mbuf,
-                               rxq->block_size - rxq->left_in_completed);
-               do {
-                       rxq->left_in_completed--;
-                       rte_mempool_put(rxq->refill_mb_pool, m);
-                       m = sfc_ef10_essb_next_mbuf(rxq, m);
-               } while (rxq->left_in_completed > 0);
-               rxq->completed++;
-       }
-
        for (i = rxq->completed; i != rxq->added; ++i) {
                rxd = &rxq->sw_ring[i & rxq->rxq_ptr_mask];
-               m = rxd->first_mbuf;
-               for (j = 0; j < rxq->block_size; ++j) {
+               m = sfc_ef10_essb_mbuf_by_index(rxq, rxd->first_mbuf,
+                               rxq->block_size - rxq->left_in_completed);
+               while (rxq->left_in_completed > 0) {
                        rte_mempool_put(rxq->refill_mb_pool, m);
                        m = sfc_ef10_essb_next_mbuf(rxq, m);
+                       rxq->left_in_completed--;
                }
+               rxq->left_in_completed = rxq->block_size;
        }
 
        rxq->flags &= ~SFC_EF10_ESSB_RXQ_STARTED;
-- 
2.17.1