Re: [PATCH v6 3/6] nvme-fc: nvme_fc_fpin_rcv() callback

[John Meneghini <jmeneghi@redhat.com>]

Reviewed-by: John Meneghini <jmeneghi@redhat.com>

On 6/20/25 1:57 PM, Bryan Gurney wrote:
> From: Hannes Reinecke <hare@kernel.org>
> 
> Add a callback nvme_fc_fpin_rcv() to evaluate the FPIN LI TLV
> information and set the 'marginal' path status for all affected
> rports.
> 
> Signed-off-by: Hannes Reinecke <hare@kernel.org>
> Tested-by: Bryan Gurney <bgurney@redhat.com>
> ---
>   drivers/nvme/host/fc.c         | 95 ++++++++++++++++++++++++++++++++++
>   include/linux/nvme-fc-driver.h |  3 ++
>   2 files changed, 98 insertions(+)
> 
> diff --git a/drivers/nvme/host/fc.c b/drivers/nvme/host/fc.c
> index 7e81c815bb83..71a77917a14f 100644
> --- a/drivers/nvme/host/fc.c
> +++ b/drivers/nvme/host/fc.c
> @@ -3724,6 +3724,101 @@ static struct nvmf_transport_ops nvme_fc_transport = {
>   	.create_ctrl	= nvme_fc_create_ctrl,
>   };
>   
> +static struct nvme_fc_rport *nvme_fc_rport_from_wwpn(struct nvme_fc_lport *lport,
> +		u64 rport_wwpn)
> +{
> +	struct nvme_fc_rport *rport;
> +
> +	list_for_each_entry(rport, &lport->endp_list, endp_list) {
> +		if (!nvme_fc_rport_get(rport))
> +			continue;
> +		if (rport->remoteport.port_name == rport_wwpn &&
> +		    rport->remoteport.port_role & FC_PORT_ROLE_NVME_TARGET)
> +			return rport;
> +		nvme_fc_rport_put(rport);
> +	}
> +	return NULL;
> +}
> +
> +static void
> +nvme_fc_fpin_li_lport_update(struct nvme_fc_lport *lport, struct fc_fn_li_desc *li)
> +{
> +	unsigned int i, pname_count = be32_to_cpu(li->pname_count);
> +	u64 attached_wwpn = be64_to_cpu(li->attached_wwpn);
> +	struct nvme_fc_rport *attached_rport;
> +
> +	for (i = 0; i < pname_count; i++) {
> +		struct nvme_fc_rport *rport;
> +		u64 wwpn = be64_to_cpu(li->pname_list[i]);
> +
> +		rport = nvme_fc_rport_from_wwpn(lport, wwpn);
> +		if (!rport)
> +			continue;
> +		if (wwpn != attached_wwpn) {
> +			struct nvme_fc_ctrl *ctrl;
> +
> +			spin_lock_irq(&rport->lock);
> +			list_for_each_entry(ctrl, &rport->ctrl_list, ctrl_list)
> +				set_bit(NVME_CTRL_MARGINAL, &ctrl->ctrl.flags);
> +			spin_unlock_irq(&rport->lock);
> +		}
> +		nvme_fc_rport_put(rport);
> +	}
> +
> +	attached_rport = nvme_fc_rport_from_wwpn(lport, attached_wwpn);
> +	if (attached_rport) {
> +		struct nvme_fc_ctrl *ctrl;
> +
> +		spin_lock_irq(&attached_rport->lock);
> +		list_for_each_entry(ctrl, &attached_rport->ctrl_list, ctrl_list)
> +			set_bit(NVME_CTRL_MARGINAL, &ctrl->ctrl.flags);
> +		spin_unlock_irq(&attached_rport->lock);
> +		nvme_fc_rport_put(attached_rport);
> +	}
> +}
> +
> +/**
> + * fc_host_fpin_rcv() - Process a received FPIN.
> + * @localport:		local port the FPIN was received on
> + * @fpin_len:		length of FPIN payload, in bytes
> + * @fpin_buf:		pointer to FPIN payload
> + * Notes:
> + *	This routine assumes no locks are held on entry.
> + */
> +void
> +nvme_fc_fpin_rcv(struct nvme_fc_local_port *localport,
> +		 u32 fpin_len, char *fpin_buf)
> +{
> +	struct nvme_fc_lport *lport;
> +	struct fc_els_fpin *fpin = (struct fc_els_fpin *)fpin_buf;
> +	union fc_tlv_desc *tlv;
> +	u32 bytes_remain;
> +	u32 dtag;
> +
> +	if (!localport)
> +		return;
> +	lport = localport_to_lport(localport);
> +	tlv = &fpin->fpin_desc[0];
> +	bytes_remain = fpin_len - offsetof(struct fc_els_fpin, fpin_desc);
> +	bytes_remain = min_t(u32, bytes_remain, be32_to_cpu(fpin->desc_len));
> +
> +	while (bytes_remain >= FC_TLV_DESC_HDR_SZ &&
> +	       bytes_remain >= FC_TLV_DESC_SZ_FROM_LENGTH(tlv)) {
> +		dtag = be32_to_cpu(tlv->hdr.desc_tag);
> +		switch (dtag) {
> +		case ELS_DTAG_LNK_INTEGRITY:
> +			nvme_fc_fpin_li_lport_update(lport, &tlv->li);
> +			break;
> +		default:
> +			break;
> +		}
> +
> +		bytes_remain -= FC_TLV_DESC_SZ_FROM_LENGTH(tlv);
> +		tlv = fc_tlv_next_desc(tlv);
> +	}
> +}
> +EXPORT_SYMBOL(nvme_fc_fpin_rcv);
> +
>   /* Arbitrary successive failures max. With lots of subsystems could be high */
>   #define DISCOVERY_MAX_FAIL	20
>   
> diff --git a/include/linux/nvme-fc-driver.h b/include/linux/nvme-fc-driver.h
> index 9f6acadfe0c8..bcd3b1e5a256 100644
> --- a/include/linux/nvme-fc-driver.h
> +++ b/include/linux/nvme-fc-driver.h
> @@ -536,6 +536,9 @@ void nvme_fc_rescan_remoteport(struct nvme_fc_remote_port *remoteport);
>   int nvme_fc_set_remoteport_devloss(struct nvme_fc_remote_port *remoteport,
>   			u32 dev_loss_tmo);
>   
> +void nvme_fc_fpin_rcv(struct nvme_fc_local_port *localport,
> +		      u32 fpin_len, char *fpin_buf);
> +
>   /*
>    * Routine called to pass a NVME-FC LS request, received by the lldd,
>    * to the nvme-fc transport.