[dpdk-dev] [PATCH v2] net/mlx5: fix split buffer Rx

[Dmitry Kozlyuk <dkozlyuk@nvidia.com>]

Routine to lookup LKey on Rx was assuming that the mbuf address
always belongs to a single mempool: the one associated with an RxQ
or the MPRQ mempool. This assumption is false for split buffers case.
A wrong LKey was looked up, resulting in completion errors.
Modify lookup routines to lookup LKey in the mbuf->pool
for non-MPRQ cases both on Rx datapath and on queue initialization.

Fixes: fec28ca0e3a9 ("net/mlx5: support mempool registration")

Signed-off-by: Dmitry Kozlyuk <dkozlyuk@nvidia.com>
Reviewed-by: Matan Azrad <matan@nvidia.com>
Reviewed-by: Viacheslav Ovsiienko <viacheslavo@nvidia.com>
---
v2: rebase on next-net-mlx

 drivers/net/mlx5/mlx5_rx.c |  5 ++++-
 drivers/net/mlx5/mlx5_rx.h | 37 +++++++++++++++++++++++++++++++++++--
 2 files changed, 39 insertions(+), 3 deletions(-)

diff --git a/drivers/net/mlx5/mlx5_rx.c b/drivers/net/mlx5/mlx5_rx.c
index 4d85f64acc..e8215f7381 100644
--- a/drivers/net/mlx5/mlx5_rx.c
+++ b/drivers/net/mlx5/mlx5_rx.c
@@ -347,6 +347,7 @@ mlx5_rxq_initialize(struct mlx5_rxq_data *rxq)
 		volatile struct mlx5_wqe_data_seg *scat;
 		uintptr_t addr;
 		uint32_t byte_count;
+		uint32_t lkey;
 
 		if (mlx5_rxq_mprq_enabled(rxq)) {
 			struct mlx5_mprq_buf *buf = (*rxq->mprq_bufs)[i];
@@ -357,6 +358,7 @@ mlx5_rxq_initialize(struct mlx5_rxq_data *rxq)
 							 1 << rxq->strd_num_n);
 			byte_count = (1 << rxq->strd_sz_n) *
 					(1 << rxq->strd_num_n);
+			lkey = mlx5_rx_addr2mr(rxq, addr);
 		} else {
 			struct rte_mbuf *buf = (*rxq->elts)[i];
 
@@ -364,13 +366,14 @@ mlx5_rxq_initialize(struct mlx5_rxq_data *rxq)
 					rxq->wqes)[i];
 			addr = rte_pktmbuf_mtod(buf, uintptr_t);
 			byte_count = DATA_LEN(buf);
+			lkey = mlx5_rx_mb2mr(rxq, buf);
 		}
 		/* scat->addr must be able to store a pointer. */
 		MLX5_ASSERT(sizeof(scat->addr) >= sizeof(uintptr_t));
 		*scat = (struct mlx5_wqe_data_seg){
 			.addr = rte_cpu_to_be_64(addr),
 			.byte_count = rte_cpu_to_be_32(byte_count),
-			.lkey = mlx5_rx_addr2mr(rxq, addr),
+			.lkey = lkey,
 		};
 	}
 	rxq->consumed_strd = 0;
diff --git a/drivers/net/mlx5/mlx5_rx.h b/drivers/net/mlx5/mlx5_rx.h
index 19d194ce12..298d1b1f32 100644
--- a/drivers/net/mlx5/mlx5_rx.h
+++ b/drivers/net/mlx5/mlx5_rx.h
@@ -291,7 +291,7 @@ uint16_t mlx5_rx_burst_mprq_vec(void *dpdk_rxq, struct rte_mbuf **pkts,
 static int mlx5_rxq_mprq_enabled(struct mlx5_rxq_data *rxq);
 
 /**
- * Query LKey from a packet buffer for Rx. No need to flush local caches
+ * Query LKey for an address on Rx. No need to flush local caches
  * as the Rx mempool database entries are valid for the lifetime of the queue.
  *
  * @param rxq
@@ -320,7 +320,40 @@ mlx5_rx_addr2mr(struct mlx5_rxq_data *rxq, uintptr_t addr)
 				     mp, addr);
 }
 
-#define mlx5_rx_mb2mr(rxq, mb) mlx5_rx_addr2mr(rxq, (uintptr_t)((mb)->buf_addr))
+/**
+ * Query LKey from a packet buffer for Rx. No need to flush local caches
+ * as the Rx mempool database entries are valid for the lifetime of the queue.
+ *
+ * @param rxq
+ *   Pointer to Rx queue structure.
+ * @param mb
+ *   Buffer to search the address of.
+ *
+ * @return
+ *   Searched LKey on success, UINT32_MAX on no match.
+ *   This function always succeeds on valid input.
+ */
+static __rte_always_inline uint32_t
+mlx5_rx_mb2mr(struct mlx5_rxq_data *rxq, struct rte_mbuf *mb)
+{
+	struct mlx5_mr_ctrl *mr_ctrl = &rxq->mr_ctrl;
+	uintptr_t addr = (uintptr_t)mb->buf_addr;
+	struct mlx5_rxq_ctrl *rxq_ctrl;
+	uint32_t lkey;
+
+	/* Linear search on MR cache array. */
+	lkey = mlx5_mr_lookup_lkey(mr_ctrl->cache, &mr_ctrl->mru,
+				   MLX5_MR_CACHE_N, addr);
+	if (likely(lkey != UINT32_MAX))
+		return lkey;
+	/*
+	 * Slower search in the mempool database on miss.
+	 * During queue creation rxq->sh is not yet set, so we use rxq_ctrl.
+	 */
+	rxq_ctrl = container_of(rxq, struct mlx5_rxq_ctrl, rxq);
+	return mlx5_mr_mempool2mr_bh(&rxq_ctrl->sh->cdev->mr_scache,
+				     mr_ctrl, mb->pool, addr);
+}
 
 /**
  * Convert timestamp from HW format to linear counter
-- 
2.25.1