net/mlx5: cleanup Rx ring in free functions

Vector PMD returns buffers to the application without setting the pointers
in the Rx queue to null nor allocating them.  When the PMD cleanup the ring
it needs to take a special care to those pointers to not free the mbufs
before the application have used them nor if the application have already
freed them.

Signed-off-by: Nelio Laranjeiro <nelio.laranjeiro@6wind.com>
Acked-by: Yongseok Koh <yskoh@mellanox.com>

diff --git a/drivers/net/mlx5/mlx5_rxq.c b/drivers/net/mlx5/mlx5_rxq.c
index de54175..2119dfa 100644 (file)
--- a/drivers/net/mlx5/mlx5_rxq.c
+++ b/drivers/net/mlx5/mlx5_rxq.c
@@ -633,32 +633,6 @@ priv_rehash_flows(struct priv *priv)
        return 0;
 }
 
-/**
- * Unlike regular Rx function, vPMD Rx doesn't replace mbufs immediately when
- * receiving packets. Instead it replaces later in bulk. In rxq->elts[], entries
- * from rq_pi to rq_ci are owned by device but the rest is already delivered to
- * application. In order not to reuse those mbufs by rxq_alloc_elts(), this
- * function must be called to replace used mbufs.
- *
- * @param rxq
- *   Pointer to RX queue structure.
- */
-static void
-rxq_trim_elts(struct rxq *rxq)
-{
-       const uint16_t q_n = (1 << rxq->elts_n);
-       const uint16_t q_mask = q_n - 1;
-       uint16_t used = q_n - (rxq->rq_ci - rxq->rq_pi);
-       uint16_t i;
-
-       if (!rxq->trim_elts)
-               return;
-       for (i = 0; i < used; ++i)
-               (*rxq->elts)[(rxq->rq_ci + i) & q_mask] = NULL;
-       rxq->trim_elts = 0;
-       return;
-}
-
 /**
  * Allocate RX queue elements.
  *
@@ -730,7 +704,6 @@ rxq_alloc_elts(struct rxq_ctrl *rxq_ctrl, unsigned int elts_n)
                /* Padding with a fake mbuf for vectorized Rx. */
                for (i = 0; i < MLX5_VPMD_DESCS_PER_LOOP; ++i)
                        (*rxq->elts)[elts_n + i] = &rxq->fake_mbuf;
-               rxq->trim_elts = 1;
        }
        DEBUG("%p: allocated and configured %u segments (max %u packets)",
              (void *)rxq_ctrl, elts_n, elts_n / (1 << rxq_ctrl->rxq.sges_n));
@@ -757,17 +730,28 @@ error:
 static void
 rxq_free_elts(struct rxq_ctrl *rxq_ctrl)
 {
-       unsigned int i;
+       struct rxq *rxq = &rxq_ctrl->rxq;
+       const uint16_t q_n = (1 << rxq->elts_n);
+       const uint16_t q_mask = q_n - 1;
+       uint16_t used = q_n - (rxq->rq_ci - rxq->rq_pi);
+       uint16_t i;
 
-       rxq_trim_elts(&rxq_ctrl->rxq);
        DEBUG("%p: freeing WRs", (void *)rxq_ctrl);
-       if (rxq_ctrl->rxq.elts == NULL)
+       if (rxq->elts == NULL)
                return;
-
-       for (i = 0; (i != (1u << rxq_ctrl->rxq.elts_n)); ++i) {
-               if ((*rxq_ctrl->rxq.elts)[i] != NULL)
-                       rte_pktmbuf_free_seg((*rxq_ctrl->rxq.elts)[i]);
-               (*rxq_ctrl->rxq.elts)[i] = NULL;
+       /**
+        * Some mbuf in the Ring belongs to the application.  They cannot be
+        * freed.
+        */
+       if (rxq_check_vec_support(rxq) > 0) {
+               for (i = 0; i < used; ++i)
+                       (*rxq->elts)[(rxq->rq_ci + i) & q_mask] = NULL;
+               rxq->rq_pi = rxq->rq_ci;
+       }
+       for (i = 0; (i != (1u << rxq->elts_n)); ++i) {
+               if ((*rxq->elts)[i] != NULL)
+                       rte_pktmbuf_free_seg((*rxq->elts)[i]);
+               (*rxq->elts)[i] = NULL;
        }
 }
 

diff --git a/drivers/net/mlx5/mlx5_rxtx.h b/drivers/net/mlx5/mlx5_rxtx.h
index d85ea16..39b217b 100644 (file)
--- a/drivers/net/mlx5/mlx5_rxtx.h
+++ b/drivers/net/mlx5/mlx5_rxtx.h
@@ -116,8 +116,7 @@ struct rxq {
        unsigned int rss_hash:1; /* RSS hash result is enabled. */
        unsigned int mark:1; /* Marked flow available on the queue. */
        unsigned int pending_err:1; /* CQE error needs to be handled. */
-       unsigned int trim_elts:1; /* Whether elts needs clean-up. */
-       unsigned int :6; /* Remaining bits. */
+       unsigned int :7; /* Remaining bits. */
        volatile uint32_t *rq_db;
        volatile uint32_t *cq_db;
        uint16_t rq_ci;