RDMA/hns: Support SRQ record doorbell

Compared with normal doorbell, using record doorbell can shorten the
process of ringing the doorbell and reduce the latency.

Add a flag HNS_ROCE_CAP_FLAG_SRQ_RECORD_DB to allow FW to
enable/disable SRQ record doorbell.

If the flag above is set, allocate the dma buffer for SRQ record
doorbell and write the buffer address into SRQC during SRQ creation.

For userspace SRQ, add a flag HNS_ROCE_RSP_SRQ_CAP_RECORD_DB to notify
userspace whether the SRQ record doorbell is enabled.

Signed-off-by: Yangyang Li <liyangyang20@huawei.com>
Signed-off-by: Junxian Huang <huangjunxian6@hisilicon.com>
Link: https://lore.kernel.org/r/20230926130026.583088-1-huangjunxian6@hisilicon.com
Signed-off-by: Leon Romanovsky <leon@kernel.org>

1 files changed, 83 insertions, 2 deletions

diff --git a/drivers/infiniband/hw/hns/hns_roce_srq.c b/drivers/infiniband/hw/hns/hns_roce_srq.c
index 8dae98f827eb..4e2d1c8e164a 100644
--- a/drivers/infiniband/hw/hns/hns_roce_srq.c
+++ b/drivers/infiniband/hw/hns/hns_roce_srq.c
@@ -5,6 +5,7 @@
 
 #include <linux/pci.h>
 #include <rdma/ib_umem.h>
+#include <rdma/uverbs_ioctl.h>
 #include "hns_roce_device.h"
 #include "hns_roce_cmd.h"
 #include "hns_roce_hem.h"
@@ -387,6 +388,79 @@ static void free_srq_buf(struct hns_roce_dev *hr_dev, struct hns_roce_srq *srq)
 	free_srq_idx(hr_dev, srq);
 }
 
+static int get_srq_ucmd(struct hns_roce_srq *srq, struct ib_udata *udata,
+			struct hns_roce_ib_create_srq *ucmd)
+{
+	struct ib_device *ibdev = srq->ibsrq.device;
+	int ret;
+
+	ret = ib_copy_from_udata(ucmd, udata, min(udata->inlen, sizeof(*ucmd)));
+	if (ret) {
+		ibdev_err(ibdev, "failed to copy SRQ udata, ret = %d.\n", ret);
+		return ret;
+	}
+
+	return 0;
+}
+
+static void free_srq_db(struct hns_roce_dev *hr_dev, struct hns_roce_srq *srq,
+			struct ib_udata *udata)
+{
+	struct hns_roce_ucontext *uctx;
+
+	if (!(srq->cap_flags & HNS_ROCE_SRQ_CAP_RECORD_DB))
+		return;
+
+	srq->cap_flags &= ~HNS_ROCE_SRQ_CAP_RECORD_DB;
+	if (udata) {
+		uctx = rdma_udata_to_drv_context(udata,
+						 struct hns_roce_ucontext,
+						 ibucontext);
+		hns_roce_db_unmap_user(uctx, &srq->rdb);
+	} else {
+		hns_roce_free_db(hr_dev, &srq->rdb);
+	}
+}
+
+static int alloc_srq_db(struct hns_roce_dev *hr_dev, struct hns_roce_srq *srq,
+			struct ib_udata *udata,
+			struct hns_roce_ib_create_srq_resp *resp)
+{
+	struct hns_roce_ib_create_srq ucmd = {};
+	struct hns_roce_ucontext *uctx;
+	int ret;
+
+	if (udata) {
+		ret = get_srq_ucmd(srq, udata, &ucmd);
+		if (ret)
+			return ret;
+
+		if ((hr_dev->caps.flags & HNS_ROCE_CAP_FLAG_SRQ_RECORD_DB) &&
+		    (ucmd.req_cap_flags & HNS_ROCE_SRQ_CAP_RECORD_DB)) {
+			uctx = rdma_udata_to_drv_context(udata,
+					struct hns_roce_ucontext, ibucontext);
+			ret = hns_roce_db_map_user(uctx, ucmd.db_addr,
+						   &srq->rdb);
+			if (ret)
+				return ret;
+
+			srq->cap_flags |= HNS_ROCE_RSP_SRQ_CAP_RECORD_DB;
+		}
+	} else {
+		if (hr_dev->caps.flags & HNS_ROCE_CAP_FLAG_SRQ_RECORD_DB) {
+			ret = hns_roce_alloc_db(hr_dev, &srq->rdb, 1);
+			if (ret)
+				return ret;
+
+			*srq->rdb.db_record = 0;
+			srq->cap_flags |= HNS_ROCE_RSP_SRQ_CAP_RECORD_DB;
+		}
+		srq->db_reg = hr_dev->reg_base + SRQ_DB_REG;
+	}
+
+	return 0;
+}
+
 int hns_roce_create_srq(struct ib_srq *ib_srq,
 			struct ib_srq_init_attr *init_attr,
 			struct ib_udata *udata)
@@ -407,15 +481,20 @@ int hns_roce_create_srq(struct ib_srq *ib_srq,
 	if (ret)
 		return ret;
 
-	ret = alloc_srqn(hr_dev, srq);
+	ret = alloc_srq_db(hr_dev, srq, udata, &resp);
 	if (ret)
 		goto err_srq_buf;
 
+	ret = alloc_srqn(hr_dev, srq);
+	if (ret)
+		goto err_srq_db;
+
 	ret = alloc_srqc(hr_dev, srq);
 	if (ret)
 		goto err_srqn;
 
 	if (udata) {
+		resp.cap_flags = srq->cap_flags;
 		resp.srqn = srq->srqn;
 		if (ib_copy_to_udata(udata, &resp,
 				     min(udata->outlen, sizeof(resp)))) {
@@ -424,7 +503,6 @@ int hns_roce_create_srq(struct ib_srq *ib_srq,
 		}
 	}
 
-	srq->db_reg = hr_dev->reg_base + SRQ_DB_REG;
 	srq->event = hns_roce_ib_srq_event;
 	refcount_set(&srq->refcount, 1);
 	init_completion(&srq->free);
@@ -435,6 +513,8 @@ err_srqc:
 	free_srqc(hr_dev, srq);
 err_srqn:
 	free_srqn(hr_dev, srq);
+err_srq_db:
+	free_srq_db(hr_dev, srq, udata);
 err_srq_buf:
 	free_srq_buf(hr_dev, srq);
 
@@ -448,6 +528,7 @@ int hns_roce_destroy_srq(struct ib_srq *ibsrq, struct ib_udata *udata)
 
 	free_srqc(hr_dev, srq);
 	free_srqn(hr_dev, srq);
+	free_srq_db(hr_dev, srq, udata);
 	free_srq_buf(hr_dev, srq);
 	return 0;
 }