[PATCH] net/gve: fix mbuf allocation memory leak for DQ Rx

[Joshua Washington]

Currently, gve_rxq_mbufs_alloc_dqo() allocates RING_SIZE buffers, but
only posts RING_SIZE - 1 of them, inevitably leaking a buffer every
time queues are stopped/started. This could eventually lead to running
out of mbufs if an application stops/starts traffic enough.

Fixes: b044845bb015 ("net/gve: support queue start/stop")
Cc: sta...@dpdk.org

Signed-off-by: Joshua Washington <joshw...@google.com>
Reviewed-by: Rushil Gupta <rush...@google.com>
Reviewed-by: Praveen Kaligineedi <pkaligine...@google.com>
---
 drivers/net/gve/gve_rx_dqo.c | 16 +++++++++-------
 1 file changed, 9 insertions(+), 7 deletions(-)

diff --git a/drivers/net/gve/gve_rx_dqo.c b/drivers/net/gve/gve_rx_dqo.c
index 60702d4100..e4084bc0dd 100644
--- a/drivers/net/gve/gve_rx_dqo.c
+++ b/drivers/net/gve/gve_rx_dqo.c
@@ -393,34 +393,36 @@ static int
 gve_rxq_mbufs_alloc_dqo(struct gve_rx_queue *rxq)
 {
        struct rte_mbuf *nmb;
+       uint16_t rx_mask;
        uint16_t i;
        int diag;
 
-       diag = rte_pktmbuf_alloc_bulk(rxq->mpool, &rxq->sw_ring[0], 
rxq->nb_rx_desc);
+       rx_mask = rxq->nb_rx_desc - 1;
+       diag = rte_pktmbuf_alloc_bulk(rxq->mpool, &rxq->sw_ring[0],
+                                     rx_mask);
        if (diag < 0) {
                rxq->stats.no_mbufs_bulk++;
-               for (i = 0; i < rxq->nb_rx_desc - 1; i++) {
+               for (i = 0; i < rx_mask; i++) {
                        nmb = rte_pktmbuf_alloc(rxq->mpool);
                        if (!nmb)
                                break;
                        rxq->sw_ring[i] = nmb;
                }
                if (i < rxq->nb_rx_desc - 1) {
-                       rxq->stats.no_mbufs += rxq->nb_rx_desc - 1 - i;
+                       rxq->stats.no_mbufs += rx_mask - i;
                        return -ENOMEM;
                }
        }
 
-       for (i = 0; i < rxq->nb_rx_desc; i++) {
-               if (i == rxq->nb_rx_desc - 1)
-                       break;
+       for (i = 0; i < rx_mask; i++) {
                nmb = rxq->sw_ring[i];
                rxq->rx_ring[i].buf_addr = 
rte_cpu_to_le_64(rte_mbuf_data_iova_default(nmb));
                rxq->rx_ring[i].buf_id = rte_cpu_to_le_16(i);
        }
+       rxq->rx_ring[rx_mask].buf_id = rte_cpu_to_le_16(rx_mask);
 
        rxq->nb_rx_hold = 0;
-       rxq->bufq_tail = rxq->nb_rx_desc - 1;
+       rxq->bufq_tail = rx_mask;
 
        rte_write32(rxq->bufq_tail, rxq->qrx_tail);
 
-- 
2.46.1.824.gd892dcdcdd-goog