[PATCH rdma-next v2 6/6] RDMA/irdma: Support UMEM attribute for SRQ creation

[David Hu <dhu@x6u.co>]

From: David Hu <xuehaohu@google.com>

Support the standard 1-step queue buffer creation for SRQ by
`UVERBS_ATTR_CREATE_SRQ_BUF_UMEM` via `ib_umem_get_attr()`.

Set up hardware pble directly from the pinned SRQ umem via
`irdma_setup_q_pbl_from_umem()`.

Proper umem and pble cleanup, and error unwind are added into existing
`irdma_srq_free_rsrc()` upon SRQ destruction.

We maintain backward compatibility for the legacy 2-step registration if
the UMEM attribute is not provided.

Signed-off-by: David Hu <xuehaohu@google.com>
---
 drivers/infiniband/hw/irdma/verbs.c | 68 ++++++++++++++++++++++++-----
 1 file changed, 58 insertions(+), 10 deletions(-)

diff --git a/drivers/infiniband/hw/irdma/verbs.c b/drivers/infiniband/hw/irdma/verbs.c
index 4f0831813119..5d085933c7f0 100644
--- a/drivers/infiniband/hw/irdma/verbs.c
+++ b/drivers/infiniband/hw/irdma/verbs.c
@@ -1996,9 +1996,16 @@ static void irdma_srq_free_rsrc(struct irdma_pci_f *rf, struct irdma_srq *iwsrq)
 		iwsrq->kmem.va = NULL;
 	} else {
 		/* Not called in any failure path, so iwpbl is valid. */
-		struct irdma_mr *iwmr = iwsrq->iwpbl->iwmr;
+		if (iwsrq->iwpbl) {
+			struct irdma_mr *iwmr = iwsrq->iwpbl->iwmr;
 
-		refcount_dec(&iwmr->user_ring_refs);
+			if (iwmr && refcount_dec_and_test(&iwmr->user_ring_refs)) {
+				ib_umem_release(iwmr->region);
+				if (iwsrq->iwpbl->pbl_allocated)
+					irdma_free_pble(rf->pble_rsrc, &iwsrq->iwpbl->pble_alloc);
+				kfree(iwmr);
+			}
+		}
 	}
 
 	irdma_free_rsrc(rf, rf->allocated_srqs, srq->srq_uk.srq_id);
@@ -2425,6 +2432,7 @@ static int irdma_setup_umode_srq(struct irdma_device *iwdev,
 				 struct ib_udata *udata,
 				 struct uverbs_attr_bundle *attrs)
 {
+	struct irdma_srq_uk_init_info *ukinfo = &info->srq_uk_init_info;
 	struct irdma_create_srq_req req = {};
 	struct irdma_ucontext *ucontext;
 	struct irdma_srq_mr *srqmr;
@@ -2440,14 +2448,49 @@ static int irdma_setup_umode_srq(struct irdma_device *iwdev,
 	if (ret)
 		return ret;
 
-	spin_lock_irqsave(&ucontext->srq_reg_mem_list_lock, flags);
-	iwpbl = irdma_get_pbl((unsigned long)req.user_srq_buf,
-			      &ucontext->srq_reg_mem_list);
-	spin_unlock_irqrestore(&ucontext->srq_reg_mem_list_lock, flags);
-	if (!iwpbl)
-		return -EPROTO;
+	if (attrs && uverbs_attr_is_valid(attrs, UVERBS_ATTR_CREATE_SRQ_BUF_UMEM)) {
+		struct irdma_mem_reg_req srq_req = {};
+		struct ib_umem *umem;
+		u32 total;
+		u8 shift;
 
-	iwsrq->iwpbl = iwpbl;
+		irdma_get_wqe_shift(ukinfo->uk_attrs, ukinfo->max_srq_frag_cnt, 0, &shift);
+		srq_req.rq_pages =
+			DIV_ROUND_UP((ukinfo->srq_size << shift) * IRDMA_QP_WQE_MIN_SIZE,
+				     IRDMA_HW_PAGE_SIZE);
+		total = srq_req.rq_pages + IRDMA_SHADOW_PGCNT;
+
+		umem = ib_umem_get_attr(&iwdev->ibdev, attrs,
+					UVERBS_ATTR_CREATE_SRQ_BUF_UMEM,
+					total << IRDMA_HW_PAGE_SHIFT,
+					IB_ACCESS_LOCAL_WRITE);
+		if (IS_ERR(umem))
+			return PTR_ERR(umem);
+
+		iwsrq->iwpbl = irdma_setup_q_pbl_from_umem(iwdev, umem,
+							   iwsrq->ibsrq.pd,
+							   IRDMA_MEMREG_TYPE_SRQ,
+							   &srq_req);
+		if (IS_ERR(iwsrq->iwpbl)) {
+			ret = PTR_ERR(iwsrq->iwpbl);
+			iwsrq->iwpbl = NULL;
+			ib_umem_release(umem);
+			return ret;
+		}
+		iwpbl = iwsrq->iwpbl;
+	} else {
+		if (!req.user_srq_buf)
+			return -EINVAL;
+
+		spin_lock_irqsave(&ucontext->srq_reg_mem_list_lock, flags);
+		iwpbl = irdma_get_pbl((unsigned long)req.user_srq_buf,
+				      &ucontext->srq_reg_mem_list);
+		spin_unlock_irqrestore(&ucontext->srq_reg_mem_list_lock, flags);
+		if (!iwpbl)
+			return -EPROTO;
+
+		iwsrq->iwpbl = iwpbl;
+	}
 	srqmr = &iwpbl->srq_mr;
 
 	if (iwpbl->pbl_allocated) {
@@ -2615,7 +2658,12 @@ static int irdma_create_srq(struct ib_srq *ibsrq,
 	if (iwsrq->user_mode && iwsrq->iwpbl) {
 		struct irdma_mr *iwmr = iwsrq->iwpbl->iwmr;
 
-		refcount_dec(&iwmr->user_ring_refs);
+		if (iwmr && refcount_dec_and_test(&iwmr->user_ring_refs)) {
+			ib_umem_release(iwmr->region);
+			if (iwsrq->iwpbl->pbl_allocated)
+				irdma_free_pble(rf->pble_rsrc, &iwsrq->iwpbl->pble_alloc);
+			kfree(iwmr);
+		}
 	}
 	irdma_free_rsrc(rf, rf->allocated_srqs, iwsrq->srq_num);
 	return err_code;
-- 
2.56.0.385.gd3acb90ef8-goog