RDMA/hns: Remove the reserved WQE of SRQ

Each SRQs contain an reserved WQE, it is inappropriate and should be
removed.

Fixes: c7bcb13 ("RDMA/hns: Add SRQ support for hip08 kernel mode")
Link: https://lore.kernel.org/r/1611997090-48820-6-git-send-email-liweihang@huawei.com
Signed-off-by: Wenpeng Liang <liangwenpeng@huawei.com>
Signed-off-by: Weihang Li <liweihang@huawei.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>

drivers/infiniband/hw/hns/hns_roce_device.h

@@ -54,6 +54,7 @@
 /* Hardware specification only for v1 engine */
 #define HNS_ROCE_MIN_CQE_NUM			0x40
 #define HNS_ROCE_MIN_WQE_NUM			0x20
+#define HNS_ROCE_MIN_SRQ_WQE_NUM		1
 
 /* Hardware specification only for v1 engine */
 #define HNS_ROCE_MAX_INNER_MTPT_NUM		0x7

drivers/infiniband/hw/hns/hns_roce_hw_v2.c

@@ -860,7 +860,7 @@ int hns_roce_srqwq_overflow(struct hns_roce_srq *srq, int nreq)
 	unsigned int cur;
 
 	cur = idx_que->head - idx_que->tail;
-	return cur + nreq >= srq->wqe_cnt - 1;
+	return cur + nreq >= srq->wqe_cnt;
 }
 
 static int find_empty_entry(struct hns_roce_idx_que *idx_que,
@@ -5338,7 +5338,7 @@ static int hns_roce_v2_modify_srq(struct ib_srq *ibsrq,
 		return -EINVAL;
 
 	if (srq_attr_mask & IB_SRQ_LIMIT) {
-		if (srq_attr->srq_limit >= srq->wqe_cnt)
+		if (srq_attr->srq_limit > srq->wqe_cnt)
 			return -EINVAL;
 
 		mailbox = hns_roce_alloc_cmd_mailbox(hr_dev);
@@ -5401,7 +5401,7 @@ static int hns_roce_v2_query_srq(struct ib_srq *ibsrq, struct ib_srq_attr *attr)
 				  SRQC_BYTE_8_SRQ_LIMIT_WL_S);
 
 	attr->srq_limit = limit_wl;
-	attr->max_wr = srq->wqe_cnt - 1;
+	attr->max_wr = srq->wqe_cnt;
 	attr->max_sge = srq->max_gs - srq->rsv_sge;
 
 out:

drivers/infiniband/hw/hns/hns_roce_srq.c

@@ -320,7 +320,7 @@ int hns_roce_create_srq(struct ib_srq *ib_srq,
 
 	max_sge = proc_srq_sge(hr_dev, srq, !!udata);
 
-	if (init_attr->attr.max_wr >= hr_dev->caps.max_srq_wrs ||
+	if (init_attr->attr.max_wr > hr_dev->caps.max_srq_wrs ||
 	    init_attr->attr.max_sge > max_sge) {
 		ibdev_err(&hr_dev->ib_dev,
 			  "SRQ config error, depth = %u, sge = %d\n",
@@ -331,7 +331,9 @@ int hns_roce_create_srq(struct ib_srq *ib_srq,
 	mutex_init(&srq->mutex);
 	spin_lock_init(&srq->lock);
 
-	srq->wqe_cnt = roundup_pow_of_two(init_attr->attr.max_wr + 1);
+	init_attr->attr.max_wr = max_t(u32, init_attr->attr.max_wr,
+				       HNS_ROCE_MIN_SRQ_WQE_NUM);
+	srq->wqe_cnt = roundup_pow_of_two(init_attr->attr.max_wr);
 	srq->max_gs =
 		roundup_pow_of_two(init_attr->attr.max_sge + srq->rsv_sge);
 	init_attr->attr.max_wr = srq->wqe_cnt;