[PATCH 26/29] ibmvfc: implement nvme-fc IO command submission callback

[Tyrel Datwyler <tyreld@linux.ibm.com>]

Add helpers to initialize an ibmvfc command from an nvmefc_fcp_req,
map request scatterlists into either an inline descriptor or an external
DMA pool list, and submit the request on the selected NVMe hardware
queue. On completion, translate ibmvfc status into the NVMe-FC response
format, including transferred length and CQE handling for no-DMA
responses.

Also store the NVMe request pointer in struct ibmvfc_event so the
completion path can finish the original request.

Signed-off-by: Tyrel Datwyler <tyreld@linux.ibm.com>
---
 drivers/scsi/ibmvscsi/ibmvfc-core.c |   2 +-
 drivers/scsi/ibmvscsi/ibmvfc-nvme.c | 140 +++++++++++++++++++++++++++-
 drivers/scsi/ibmvscsi/ibmvfc.h      |   1 +
 3 files changed, 141 insertions(+), 2 deletions(-)

diff --git a/drivers/scsi/ibmvscsi/ibmvfc-core.c b/drivers/scsi/ibmvscsi/ibmvfc-core.c
index 177d341ce7bc..a7183493cf96 100644
--- a/drivers/scsi/ibmvscsi/ibmvfc-core.c
+++ b/drivers/scsi/ibmvscsi/ibmvfc-core.c
@@ -1539,7 +1539,7 @@ static void ibmvfc_set_login_info(struct ibmvfc_host *vhost)
 
 	login_info->ostype = cpu_to_be32(IBMVFC_OS_LINUX);
 	login_info->max_dma_len = cpu_to_be64(max_sectors << 9);
-	login_info->max_payload = cpu_to_be32(sizeof(struct ibmvfc_fcp_cmd_iu));
+	login_info->max_payload = cpu_to_be32(sizeof(struct nvme_fc_cmd_iu));
 	login_info->max_response = cpu_to_be32(sizeof(struct ibmvfc_fcp_rsp));
 	login_info->partition_num = cpu_to_be32(vhost->partition_number);
 	login_info->vfc_frame_version = cpu_to_be32(1);
diff --git a/drivers/scsi/ibmvscsi/ibmvfc-nvme.c b/drivers/scsi/ibmvscsi/ibmvfc-nvme.c
index 506135c1a34e..bff469d0b47d 100644
--- a/drivers/scsi/ibmvscsi/ibmvfc-nvme.c
+++ b/drivers/scsi/ibmvscsi/ibmvfc-nvme.c
@@ -8,6 +8,7 @@
  * Copyright (C) IBM Corporation, 2026
  */
 
+#include <linux/dmapool.h>
 #include <scsi/scsi_transport_fc.h>
 
 #include "ibmvfc-nvme.h"
@@ -164,12 +165,149 @@ static void ibmvfc_nvme_ls_abort(struct nvme_fc_local_port *lport,
 {
 }
 
+static void ibmvfc_nvme_done(struct ibmvfc_event *evt)
+{
+	struct ibmvfc_cmd *vfc_cmd = &evt->xfer_iu->cmd;
+	struct nvmefc_fcp_req *fcp_req = evt->fcp_req;
+	struct nvme_fc_ersp_iu *ersp = (struct nvme_fc_ersp_iu *)fcp_req->rspaddr;
+	struct nvme_completion *cqe = &ersp->cqe;
+	struct nvme_command *sqe = &((struct nvme_fc_cmd_iu *)fcp_req->cmdaddr)->sqe;
+
+	ibmvfc_dbg(evt->vhost, "fc_done: (%x:%x)\n", be16_to_cpu(vfc_cmd->status),
+		   be16_to_cpu(vfc_cmd->error));
+	ibmvfc_dbg(evt->vhost, "fc_done: cmdlen: %d, rsplen %d, payload_len %d\n",
+		   fcp_req->cmdlen, fcp_req->rsplen, fcp_req->payload_length);
+
+	fcp_req->status = 0;
+	if (!vfc_cmd->status) {
+		fcp_req->rcv_rsplen = NVME_FC_SIZEOF_ZEROS_RSP;
+		fcp_req->transferred_length = fcp_req->payload_length;
+	} else if (be16_to_cpu(vfc_cmd->status) & IBMVFC_FC_NVME_STATUS) {
+		fcp_req->rcv_rsplen = sizeof(struct nvme_fc_ersp_iu);
+		fcp_req->transferred_length = be32_to_cpu(ersp->xfrd_len);
+		if (be16_to_cpu(vfc_cmd->error) & IBMVFC_NVMS_VALID_NODMA_CQE)
+			cqe->command_id = sqe->common.command_id;
+	} else {
+		fcp_req->rcv_rsplen = 0;
+		fcp_req->transferred_length = 0;
+		fcp_req->status = NVME_SC_INTERNAL;
+	}
+
+	fcp_req->done(fcp_req);
+	ibmvfc_free_event(evt);
+}
+
+static struct ibmvfc_cmd *ibmvfc_nvme_init_vfc_cmd(struct ibmvfc_event *evt,
+						   struct nvme_fc_remote_port *rport,
+						   struct nvmefc_fcp_req *fcp_req)
+{
+	struct ibmvfc_target *tgt = rport->private;
+	struct ibmvfc_cmd *vfc_cmd = &evt->iu.cmd;
+
+	memset(vfc_cmd, 0, sizeof(*vfc_cmd));
+
+	vfc_cmd->resp.va = cpu_to_be64(fcp_req->rspdma);
+	vfc_cmd->resp.len = cpu_to_be32(fcp_req->rsplen);
+	vfc_cmd->frame_type = cpu_to_be32(IBMVFC_NVME_FCP_TYPE);
+	vfc_cmd->flags |= cpu_to_be16(IBMVFC_NVMEOF_PROTOCOL);
+	vfc_cmd->payload_len = cpu_to_be32(fcp_req->cmdlen);
+	vfc_cmd->resp_len = cpu_to_be32(fcp_req->rsplen);
+	vfc_cmd->cancel_key = cpu_to_be32((u64)evt);
+	vfc_cmd->target_wwpn = cpu_to_be64(rport->port_name);
+	vfc_cmd->tgt_scsi_id = cpu_to_be64(rport->port_id);
+	vfc_cmd->assoc_id = cpu_to_be64(tgt->assoc_id);
+
+	memcpy(&vfc_cmd->v3nvme.iu, fcp_req->cmdaddr, fcp_req->cmdlen);
+
+	return vfc_cmd;
+}
+
+static void ibmvfc_nvme_map_sg_list(struct nvmefc_fcp_req *fcp_req,
+				    struct srp_direct_buf *md)
+{
+	int i;
+	struct scatterlist *sg;
+
+	for_each_sg(fcp_req->first_sgl, sg, fcp_req->sg_cnt, i) {
+		md[i].va = cpu_to_be64(sg_dma_address(sg));
+		md[i].len = cpu_to_be32(sg_dma_len(sg));
+		md[i].key = 0;
+	}
+}
+
+static int ibmvfc_nvme_map_sg_data(struct nvmefc_fcp_req *fcp_req,
+				    struct ibmvfc_event *evt,
+				    struct ibmvfc_cmd *vfc_cmd)
+{
+	struct srp_direct_buf *data = &vfc_cmd->ioba;
+	struct ibmvfc_host *vhost = evt->vhost;
+
+	if (!fcp_req->sg_cnt) {
+		vfc_cmd->flags |= cpu_to_be16(IBMVFC_NO_MEM_DESC);
+		return 0;
+	}
+
+	if (fcp_req->io_dir == NVMEFC_FCP_WRITE)
+		vfc_cmd->flags |= cpu_to_be16(IBMVFC_WRITE);
+	else
+		vfc_cmd->flags |= cpu_to_be16(IBMVFC_READ);
+
+	if (fcp_req->sg_cnt == 1) {
+		ibmvfc_nvme_map_sg_list(fcp_req, data);
+		return 0;
+	}
+
+	vfc_cmd->flags |= cpu_to_be16(IBMVFC_SCATTERLIST);
+
+	if (!evt->ext_list) {
+		evt->ext_list = dma_pool_alloc(vhost->sg_pool, GFP_ATOMIC,
+					       &evt->ext_list_token);
+
+		if (!evt->ext_list)
+			return -ENOMEM;
+	}
+
+	ibmvfc_nvme_map_sg_list(fcp_req, evt->ext_list);
+
+	data->va = cpu_to_be64(evt->ext_list_token);
+	data->len = cpu_to_be32(fcp_req->sg_cnt * sizeof(struct srp_direct_buf));
+	data->key = 0;
+	return 0;
+}
+
 static int ibmvfc_nvme_fcp_io(struct nvme_fc_local_port *lport,
 			      struct nvme_fc_remote_port *rport,
 			      void *hw_queue_handle,
 			      struct nvmefc_fcp_req *fcp_req)
 {
-	return 0;
+	struct ibmvfc_host *vhost = lport->private;
+	struct ibmvfc_nvme_qhandle *qhandle = hw_queue_handle;
+	struct ibmvfc_cmd *vfc_cmd;
+	struct ibmvfc_event *evt;
+	int rc;
+
+	ibmvfc_dbg(vhost, "nvme_fcp_io\n");
+	evt = ibmvfc_get_event(qhandle->queue);
+	if (!evt)
+		return -EBUSY;
+
+	evt->hwq = qhandle->index;
+	ibmvfc_dbg(vhost, "vfc-nvme-mq-%d\n", evt->hwq);
+
+	ibmvfc_init_event(evt, ibmvfc_nvme_done, IBMVFC_CMD_FORMAT);
+	evt->fcp_req = fcp_req;
+	fcp_req->private = evt;
+
+	vfc_cmd = ibmvfc_nvme_init_vfc_cmd(evt, rport, fcp_req);
+
+	vfc_cmd->correlation = cpu_to_be64((u64)evt);
+
+	if (likely(!(rc = ibmvfc_nvme_map_sg_data(fcp_req, evt, vfc_cmd))))
+		return ibmvfc_send_event(evt, vhost, 0);
+
+	ibmvfc_free_event(evt);
+
+	return rc;
 }
 
 static void ibmvfc_nvme_fcp_abort(struct nvme_fc_local_port *lport,
diff --git a/drivers/scsi/ibmvscsi/ibmvfc.h b/drivers/scsi/ibmvscsi/ibmvfc.h
index 9f6705e604fd..ca80ceffe53a 100644
--- a/drivers/scsi/ibmvscsi/ibmvfc.h
+++ b/drivers/scsi/ibmvscsi/ibmvfc.h
@@ -853,6 +853,7 @@ struct ibmvfc_event {
 	struct ibmvfc_target *tgt;
 	struct scsi_cmnd *cmnd;
 	struct nvmefc_ls_req *ls_req;
+	struct nvmefc_fcp_req *fcp_req;
 	atomic_t free;
 	atomic_t active;
 	union ibmvfc_iu *xfer_iu;
-- 
2.54.0