[PATCH v5 09/13] scsi: fnic: Send NVMe LS requests through FDLS

[Karan Tilak Kumar <kartilak@cisco.com>]

Add the FC frame wrapper for NVMe LS requests and build LS request
frames from the NVMe-FC transport callback.

Allocate OXIDs, track outstanding LS requests on the target port, arm
request timers, and register the LS request callback in the NVMe FC
port template.

Reported-by: kernel test robot <lkp@intel.com>
Closes: https://lore.kernel.org/oe-kbuild-all/202605280619.pmobiDWp-lkp@intel.com/
Reviewed-by: Sesidhar Baddela <sebaddel@cisco.com>
Reviewed-by: Arulprabhu Ponnusamy <arulponn@cisco.com>
Reviewed-by: Gian Carlo Boffa <gcboffa@cisco.com>
Reviewed-by: Arun Easi <aeasi@cisco.com>
Reviewed-by: Hannes Reinecke <hare@kernel.org>
Reviewed-by: Lee Duncan <lduncan@suse.com>
Signed-off-by: Karan Tilak Kumar <kartilak@cisco.com>
Co-developed-by: Hannes Reinecke <hare@kernel.org>

---
Changes between v2 and v3:
Fix issues reported by kernel bot.
Guard tport logging when NVMe LS send has no tport.

Changes between v3 and v4:
Incorporate review comments from Sashiko:
	Arm NVMe LS request timer before exposing the request

Changes between v4 and v5:
Incorporate review comments from Sashiko:
	Avoid NVMe LS request send races
---
 drivers/scsi/fnic/fdls_fc.h   |   3 +
 drivers/scsi/fnic/fnic_nvme.c | 125 +++++++++++++++++++++++++++++++++-
 drivers/scsi/fnic/fnic_nvme.h |   3 +
 3 files changed, 130 insertions(+), 1 deletion(-)

diff --git a/drivers/scsi/fnic/fdls_fc.h b/drivers/scsi/fnic/fdls_fc.h
index a7b8b969f019..cdf84462dd37 100644
--- a/drivers/scsi/fnic/fdls_fc.h
+++ b/drivers/scsi/fnic/fdls_fc.h
@@ -30,6 +30,9 @@
 #include <linux/if_ether.h>
 #include <scsi/fc/fc_encaps.h>
 #include <scsi/fc/fc_fcoe.h>
+#include <linux/nvme.h>
+#include <linux/nvme-fc.h>
+#include <linux/nvme-fc-driver.h>
 
 #define FDLS_MIN_FRAMES	(32)
 #define FDLS_MIN_FRAME_ELEM	(4)
diff --git a/drivers/scsi/fnic/fnic_nvme.c b/drivers/scsi/fnic/fnic_nvme.c
index 8374464e4fcc..16e2f0add5ce 100644
--- a/drivers/scsi/fnic/fnic_nvme.c
+++ b/drivers/scsi/fnic/fnic_nvme.c
@@ -1306,6 +1306,129 @@ void nvfnic_ls_req_timeout(struct timer_list *t)
 	ls_req->done(ls_req, -ETIMEDOUT);
 }
 
+/**
+ * nvfnic_ls_req_send - Send NVMe FC link service (LS) request
+ * @lport:   Pointer to local NVMe FC port structure
+ * @rport:   Pointer to remote NVMe FC port structure
+ * @ls_req:  Pointer to the link service request structure
+ *
+ * This function is used to send link service (LS) commands to an NVMe
+ * Discovery Controller for discovery operations, as well as to regular
+ * NVMe subsystems during association. It encapsulates the logic for
+ * transmitting LS requests over the NVMe over Fabrics (NVMe-oF) FC
+ * transport.
+ *
+ * Returns: 0 on success, or a negative error code on failure.
+ */
+int nvfnic_ls_req_send(struct nvme_fc_local_port *lport,
+		  struct nvme_fc_remote_port *rport,
+		  struct nvmefc_ls_req *ls_req)
+{
+	int timeout;
+	uint8_t *frame;
+	uint8_t fcid[3];
+	unsigned long flags = 0;
+	struct fnic_iport_s *iport = lport->private;
+	uint8_t *ls_req_payload;
+	struct fnic *fnic = iport->fnic;
+	struct fc_frame_header *fchdr;
+	struct nvfnic_ls_req *nvfnic_ls_req = ls_req->private;
+	uint16_t frame_size = FNIC_ETH_FCOE_HDRS_OFFSET +
+			sizeof(struct fc_frame_header) + ls_req->rqstlen;
+	struct fnic_tport_s *tport;
+	int ret;
+
+	spin_lock_irqsave(&fnic->fnic_lock, flags);
+
+	tport = (struct fnic_tport_s *)rport->private;
+	INIT_LIST_HEAD(&nvfnic_ls_req->list);
+
+	if (!nvfnic_transport_ready(iport, tport)) {
+		if (tport != NULL)
+			FNIC_NVME_DBG(KERN_INFO, fnic,
+				      "iport: 0x%x tport: 0x%x transport not ready\n",
+				      iport->fcid, tport->fcid);
+		else
+			FNIC_NVME_DBG(KERN_INFO, fnic,
+				      "iport: 0x%x transport not ready\n",
+				      iport->fcid);
+		spin_unlock_irqrestore(&fnic->fnic_lock, flags);
+		return -ENOLINK;
+	}
+
+	frame = fdls_alloc_frame(iport);
+	if (frame == NULL) {
+		FNIC_NVME_DBG(KERN_ERR, fnic,
+		     "Failed to allocate frame to send NVME LS REQ");
+		spin_unlock_irqrestore(&fnic->fnic_lock, flags);
+		return -ENOMEM;
+	}
+
+	if (fdls_alloc_oxid(iport, FNIC_FRAME_TYPE_NVME_LS,
+			&nvfnic_ls_req->oxid) == FNIC_UNASSIGNED_OXID) {
+		FNIC_FCS_DBG(KERN_INFO, fnic,
+		     "0x%x: Failed to allocate OXID to send NVME LS REQ",
+			 iport->fcid);
+		mempool_free(frame, fnic->frame_pool);
+		spin_unlock_irqrestore(&fnic->fnic_lock, flags);
+		return -EAGAIN;
+	}
+
+	timer_setup(&nvfnic_ls_req->ls_req_timer, nvfnic_ls_req_timeout,
+		     0UL);
+
+	nvfnic_ls_req->fnic = fnic;
+	nvfnic_ls_req->tport = tport;
+	nvfnic_ls_req->state = FNIC_LS_REQ_CMD_INIT;
+	nvfnic_ls_req->ls_req = ls_req;
+
+	fchdr = (struct fc_frame_header *)(frame + FNIC_ETH_FCOE_HDRS_OFFSET);
+	*fchdr = (struct fc_frame_header) {
+		.fh_r_ctl = FC_RCTL_ELS4_REQ,
+		.fh_type = FC_TYPE_NVME,
+		.fh_f_ctl = {FNIC_ELS_REQ_FCTL, 0, 0},
+		.fh_rx_id = cpu_to_be16(FNIC_UNASSIGNED_RXID)
+	};
+
+	hton24(fcid, iport->fcid);
+	FNIC_STD_SET_S_ID(*fchdr, fcid);
+
+	hton24(fcid, tport->fcid);
+	FNIC_STD_SET_D_ID(*fchdr, fcid);
+
+	FNIC_STD_SET_OX_ID(*fchdr, nvfnic_ls_req->oxid);
+
+	ls_req_payload = frame + FNIC_ETH_FCOE_HDRS_OFFSET + sizeof(*fchdr);
+	memcpy(ls_req_payload, ls_req->rqstaddr, ls_req->rqstlen);
+
+	FNIC_NVME_DBG(KERN_INFO, fnic,
+		 "0x%x: NVME send ls req with oxid: 0x%x type: 0x%02x len: %d",
+		 iport->fcid, nvfnic_ls_req->oxid, *((uint8_t *) ls_req->rqstaddr),
+		 ls_req->rqstlen);
+
+	list_add_tail(&nvfnic_ls_req->list, &tport->ls_req_list);
+	nvfnic_ls_req->state = FNIC_LS_REQ_CMD_PENDING;
+
+	ret = fnic_send_fcoe_frame(iport, frame, frame_size);
+	if (ret) {
+		list_del(&nvfnic_ls_req->list);
+		fdls_free_oxid(iport, nvfnic_ls_req->oxid,
+			       &nvfnic_ls_req->oxid);
+		nvfnic_ls_req->state = FNIC_LS_REQ_CMD_COMPLETE;
+		ls_req->private = NULL;
+		spin_unlock_irqrestore(&fnic->fnic_lock, flags);
+		mempool_free(frame, fnic->frame_pool);
+		return ret;
+	}
+
+	timeout = FNIC_LS_REQ_TMO_MSECS(ls_req->timeout);
+	mod_timer(&nvfnic_ls_req->ls_req_timer,
+		  round_jiffies(jiffies + msecs_to_jiffies(timeout)));
+	spin_unlock_irqrestore(&fnic->fnic_lock, flags);
+
+	return 0;
+}
+
 void nvfnic_local_port_delete(struct nvme_fc_local_port *lport)
 {
 	struct fnic_iport_s *iport = (struct fnic_iport_s *) lport->private;
@@ -1606,7 +1729,7 @@ nvme_fc_port_template nvfnic_port = {
 	.remoteport_delete = nvfnic_remote_port_delete,
 	.create_queue = nvfnic_create_queue,
 	.delete_queue = NULL,
-	.ls_req = NULL,
+	.ls_req = nvfnic_ls_req_send,
 	.ls_abort = nvfnic_ls_req_abort,
 	.fcp_io = nvfnic_fcpio_send,
 	.fcp_abort = nvfnic_fcpio_abort,
diff --git a/drivers/scsi/fnic/fnic_nvme.h b/drivers/scsi/fnic/fnic_nvme.h
index ab96b8d13931..ebdaf6930f8e 100644
--- a/drivers/scsi/fnic/fnic_nvme.h
+++ b/drivers/scsi/fnic/fnic_nvme.h
@@ -111,6 +111,9 @@ void nvfnic_ls_req_abort(struct nvme_fc_local_port *lport,
 			 struct nvmefc_ls_req *lsreq);
 int nvfnic_create_queue(struct nvme_fc_local_port *lport, unsigned int idx,
 			u16 size, void **handle);
+int nvfnic_ls_req_send(struct nvme_fc_local_port *lport,
+		       struct nvme_fc_remote_port *rport,
+		       struct nvmefc_ls_req *ls_req);
 void nvfnic_ls_req_timeout(struct timer_list *t);
 uint16_t nvfnic_alloc_ls_req_oxid(struct fnic_iport_s *iport);
 struct nvfnic_ls_req *nvfnic_find_ls_req(struct fnic_tport_s *tport,
-- 
2.47.1