From: Jacob Moroni <jmoroni@google.com>
Date: Tue, 25 Nov 2025 02:53:49 +0000 (-0600)
Subject: RDMA/irdma: Remove doorbell elision logic
X-Git-Tag: v6.19-rc1~130^2~5
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=62356fccb195f83d2ceafc787c5ba87ebbe5edfe;p=thirdparty%2Fkernel%2Flinux.git

RDMA/irdma: Remove doorbell elision logic

In some cases, this logic can result in doorbell writes being
skipped when they should not have been (at least on GEN3 HW),
so remove it. This also means that the mb() can be safely
downgraded to dma_wmb().

Fixes: 551c46edc769 ("RDMA/irdma: Add user/kernel shared libraries")
Signed-off-by: Jacob Moroni <jmoroni@google.com>
Signed-off-by: Tatyana Nikolova <tatyana.e.nikolova@intel.com>
Link: https://patch.msgid.link/20251125025350.180-9-tatyana.e.nikolova@intel.com
Signed-off-by: Leon Romanovsky <leon@kernel.org>
---

diff --git a/drivers/infiniband/hw/irdma/puda.c b/drivers/infiniband/hw/irdma/puda.c
index 3c29e22893225..cee47ddbd1b59 100644
--- a/drivers/infiniband/hw/irdma/puda.c
+++ b/drivers/infiniband/hw/irdma/puda.c
@@ -685,7 +685,6 @@ static int irdma_puda_qp_create(struct irdma_puda_rsrc *rsrc)
 	ukqp->rq_size = rsrc->rq_size;
 
 	IRDMA_RING_INIT(ukqp->sq_ring, ukqp->sq_size);
-	IRDMA_RING_INIT(ukqp->initial_ring, ukqp->sq_size);
 	IRDMA_RING_INIT(ukqp->rq_ring, ukqp->rq_size);
 	ukqp->wqe_alloc_db = qp->pd->dev->wqe_alloc_db;
 
diff --git a/drivers/infiniband/hw/irdma/uk.c b/drivers/infiniband/hw/irdma/uk.c
index 8a463b3d4c838..f0846b800913d 100644
--- a/drivers/infiniband/hw/irdma/uk.c
+++ b/drivers/infiniband/hw/irdma/uk.c
@@ -114,33 +114,8 @@ void irdma_clr_wqes(struct irdma_qp_uk *qp, u32 qp_wqe_idx)
  */
 void irdma_uk_qp_post_wr(struct irdma_qp_uk *qp)
 {
-	u64 temp;
-	u32 hw_sq_tail;
-	u32 sw_sq_head;
-
-	/* valid bit is written and loads completed before reading shadow */
-	mb();
-
-	/* read the doorbell shadow area */
-	get_64bit_val(qp->shadow_area, 0, &temp);
-
-	hw_sq_tail = (u32)FIELD_GET(IRDMA_QP_DBSA_HW_SQ_TAIL, temp);
-	sw_sq_head = IRDMA_RING_CURRENT_HEAD(qp->sq_ring);
-	if (sw_sq_head != qp->initial_ring.head) {
-		if (sw_sq_head != hw_sq_tail) {
-			if (sw_sq_head > qp->initial_ring.head) {
-				if (hw_sq_tail >= qp->initial_ring.head &&
-				    hw_sq_tail < sw_sq_head)
-					writel(qp->qp_id, qp->wqe_alloc_db);
-			} else {
-				if (hw_sq_tail >= qp->initial_ring.head ||
-				    hw_sq_tail < sw_sq_head)
-					writel(qp->qp_id, qp->wqe_alloc_db);
-			}
-		}
-	}
-
-	qp->initial_ring.head = qp->sq_ring.head;
+	dma_wmb();
+	writel(qp->qp_id, qp->wqe_alloc_db);
 }
 
 /**
@@ -1606,7 +1581,6 @@ static void irdma_setup_connection_wqes(struct irdma_qp_uk *qp,
 	qp->conn_wqes = move_cnt;
 	IRDMA_RING_MOVE_HEAD_BY_COUNT_NOCHECK(qp->sq_ring, move_cnt);
 	IRDMA_RING_MOVE_TAIL_BY_COUNT(qp->sq_ring, move_cnt);
-	IRDMA_RING_MOVE_HEAD_BY_COUNT_NOCHECK(qp->initial_ring, move_cnt);
 }
 
 /**
@@ -1751,7 +1725,6 @@ int irdma_uk_qp_init(struct irdma_qp_uk *qp, struct irdma_qp_uk_init_info *info)
 	qp->max_sq_frag_cnt = info->max_sq_frag_cnt;
 	sq_ring_size = qp->sq_size << info->sq_shift;
 	IRDMA_RING_INIT(qp->sq_ring, sq_ring_size);
-	IRDMA_RING_INIT(qp->initial_ring, sq_ring_size);
 	if (info->first_sq_wq) {
 		irdma_setup_connection_wqes(qp, info);
 		qp->swqe_polarity = 1;
diff --git a/drivers/infiniband/hw/irdma/user.h b/drivers/infiniband/hw/irdma/user.h
index 3a27cce3c3dbc..9eb7fd0b1cbf9 100644
--- a/drivers/infiniband/hw/irdma/user.h
+++ b/drivers/infiniband/hw/irdma/user.h
@@ -457,7 +457,6 @@ struct irdma_srq_uk {
 	struct irdma_uk_attrs *uk_attrs;
 	__le64 *shadow_area;
 	struct irdma_ring srq_ring;
-	struct irdma_ring initial_ring;
 	u32 srq_id;
 	u32 srq_size;
 	u32 max_srq_frag_cnt;