debian/patches/providers-mana-fix-WRs-with-zero-sges.patch

From: Konstantin Taranov <kotaranov@microsoft.com>
Date: Thu, 5 Sep 2024 14:05:11 +0200
Subject: providers/mana: fix WRs with zero sges

The HW requires at least one SGE posted in work queues.
Add dummy SGE when zero SGEs are requested in receive WRs.

Fixes: ec26fedd55e0 ("providers/mana: Post recv and post send")
Signed-off-by: Konstantin Taranov <kotaranov@microsoft.com>
Origin: upstream, https://github.com/linux-rdma/rdma-core/pull/1556
---
 providers/mana/qp.c | 11 ++++++++---
 providers/mana/wr.c | 14 ++++++++++----
 2 files changed, 18 insertions(+), 7 deletions(-)

diff --git a/providers/mana/qp.c b/providers/mana/qp.c
index a6b28d5..a318620 100644
--- a/providers/mana/qp.c
+++ b/providers/mana/qp.c
@@ -180,12 +180,15 @@ struct mana_qp *mana_get_qp_from_rq(struct mana_context *ctx, uint32_t qid)
 static uint32_t get_queue_size(struct ibv_qp_init_attr *attr, enum user_queue_types type)
 {
 	uint32_t size = 0;
+	uint32_t sges = 0;
 
 	if (attr->qp_type == IBV_QPT_RC) {
 		switch (type) {
 		case USER_RC_SEND_QUEUE_REQUESTER:
-			/* For write with imm we need +1 */
-			size = attr->cap.max_send_wr * get_large_wqe_size(attr->cap.max_send_sge + 1);
+			/* WQE must have at least one SGE */
+			/* For write with imm we need one extra SGE */
+			sges = max(1U, attr->cap.max_send_sge) + 1;
+			size = attr->cap.max_send_wr * get_large_wqe_size(sges);
 			break;
 		case USER_RC_SEND_QUEUE_RESPONDER:
 			size = MANA_PAGE_SIZE;
@@ -194,7 +197,9 @@ static uint32_t get_queue_size(struct ibv_qp_init_attr *attr, enum user_queue_ty
 			size = MANA_PAGE_SIZE;
 			break;
 		case USER_RC_RECV_QUEUE_RESPONDER:
-			size = attr->cap.max_recv_wr * get_wqe_size(attr->cap.max_recv_sge);
+			/* WQE must have at least one SGE */
+			sges = max(1U, attr->cap.max_recv_sge);
+			size = attr->cap.max_recv_wr * get_wqe_size(sges);
 			break;
 		default:
 			return 0;
diff --git a/providers/mana/wr.c b/providers/mana/wr.c
index 5975971..755e6a8 100644
--- a/providers/mana/wr.c
+++ b/providers/mana/wr.c
@@ -106,12 +106,18 @@ static inline void gdma_write_sge(struct gdma_wqe *wqe, void *oob_sge,
 }
 
 static inline int
-gdma_post_rq_wqe(struct mana_gdma_queue *wq, struct ibv_sge *sgl,  void *oob,
+gdma_post_rq_wqe(struct mana_gdma_queue *wq, struct ibv_sge *sgl,  struct rdma_recv_oob *recv_oob,
 		 uint32_t num_sge, enum gdma_work_req_flags flags, struct gdma_wqe *wqe)
 {
-	uint32_t wqe_size = get_wqe_size(num_sge);
+	struct ibv_sge dummy = {1, 0, 0};
+	uint32_t wqe_size;
 	int ret;
 
+	if (num_sge == 0) {
+		num_sge = 1;
+		sgl = &dummy;
+	}
+	wqe_size = get_wqe_size(num_sge);
 	ret = gdma_get_current_wqe(wq, INLINE_OOB_SMALL_SIZE, wqe_size, wqe);
 	if (ret)
 		return ret;
@@ -119,8 +125,8 @@ gdma_post_rq_wqe(struct mana_gdma_queue *wq, struct ibv_sge *sgl,  void *oob,
 	wqe->gdma_oob->rx.num_sgl_entries = num_sge;
 	wqe->gdma_oob->rx.inline_client_oob_size = INLINE_OOB_SMALL_SIZE / sizeof(uint32_t);
 	wqe->gdma_oob->rx.check_sn = (flags & GDMA_WORK_REQ_CHECK_SN) != 0;
-	if (oob)
-		memcpy(wqe->client_oob, oob, INLINE_OOB_SMALL_SIZE);
+	if (recv_oob)
+		memcpy(wqe->client_oob, recv_oob, INLINE_OOB_SMALL_SIZE);
 
 	gdma_write_sge(wqe, NULL, sgl, num_sge);
 	gdma_advance_producer(wq, wqe->size_in_bu);