RE: [PATCH v2] scsi: storvsc: Add support for FC rport.

[KY Srinivasan]

> -----Original Message-----
> From: Cathy Avery [mailto:cavery@xxxxxxxxxx]
> Sent: Friday, March 17, 2017 8:18 AM
> To: KY Srinivasan <kys@xxxxxxxxxxxxx>; hch@xxxxxxxxxxxxx; Haiyang Zhang
> <haiyangz@xxxxxxxxxxxxx>; jejb@xxxxxxxxxxxxxxxxxx;
> martin.petersen@xxxxxxxxxx
> Cc: stephen@xxxxxxxxxxxxxxxxxx; dan.carpenter@xxxxxxxxxx;
> devel@xxxxxxxxxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx; linux-
> scsi@xxxxxxxxxxxxxxx
> Subject: [PATCH v2] scsi: storvsc: Add support for FC rport.
> 
> Included in the current storvsc driver for Hyper-V is the ability
> to access luns on an FC fabric via a virtualized fiber channel
> adapter exposed by the Hyper-V host. The driver also attaches to
> the FC transport to allow host and port names to be published under
> /sys/class/fc_host/hostX. Current customer tools running on the VM
> require that these names be available in the well known standard
> location under fc_host/hostX.
> 
> A problem arose when attaching to the FC transport. The scsi_scan
> code attempts to call fc_user_scan which has basically become a no-op
> due to the fact that the virtualized FC device does not expose rports.
> At this point you cannot refresh the scsi bus after mapping or unmapping
> luns on the SAN without a reboot of the VM.
> 
> This patch stubs in an rport per fc_host in storvsc so that the
> requirement of a defined rport is now met within the fc_transport and
> echo "- - -" > /sys/class/scsi_host/hostX/scan now works.
> 
> Signed-off-by: Cathy Avery <cavery@xxxxxxxxxx>

Acked-by: K. Y. Srinivasan <kys@xxxxxxxxxxxxx>
> ---
> Changes since v1:
> - Fix fc_rport_identifiers init [Stephen Hemminger]
> - Better error checking
> ---
>  drivers/scsi/storvsc_drv.c | 23 ++++++++++++++++++-----
>  1 file changed, 18 insertions(+), 5 deletions(-)
> 
> diff --git a/drivers/scsi/storvsc_drv.c b/drivers/scsi/storvsc_drv.c
> index 638e5f4..37646d1 100644
> --- a/drivers/scsi/storvsc_drv.c
> +++ b/drivers/scsi/storvsc_drv.c
> @@ -478,6 +478,9 @@ struct storvsc_device {
>  	 */
>  	u64 node_name;
>  	u64 port_name;
> +#if IS_ENABLED(CONFIG_SCSI_FC_ATTRS)
> +	struct fc_rport *rport;
> +#endif
>  };
> 
>  struct hv_host_device {
> @@ -1816,19 +1819,27 @@ static int storvsc_probe(struct hv_device
> *device,
>  		target = (device->dev_instance.b[5] << 8 |
>  			 device->dev_instance.b[4]);
>  		ret = scsi_add_device(host, 0, target, 0);
> -		if (ret) {
> -			scsi_remove_host(host);
> -			goto err_out2;
> -		}
> +		if (ret)
> +			goto err_out3;
>  	}
>  #if IS_ENABLED(CONFIG_SCSI_FC_ATTRS)
>  	if (host->transportt == fc_transport_template) {
> +		struct fc_rport_identifiers ids = {
> +			.roles = FC_PORT_ROLE_FCP_TARGET,
> +		};
> +
>  		fc_host_node_name(host) = stor_device->node_name;
>  		fc_host_port_name(host) = stor_device->port_name;
> +		stor_device->rport = fc_remote_port_add(host, 0, &ids);
> +		if (!stor_device->rport)
> +			goto err_out3;
>  	}
>  #endif
>  	return 0;
> 
> +err_out3:
> +	scsi_remove_host(host);
> +
>  err_out2:
>  	/*
>  	 * Once we have connected with the host, we would need to
> @@ -1854,8 +1865,10 @@ static int storvsc_remove(struct hv_device *dev)
>  	struct Scsi_Host *host = stor_device->host;
> 
>  #if IS_ENABLED(CONFIG_SCSI_FC_ATTRS)
> -	if (host->transportt == fc_transport_template)
> +	if (host->transportt == fc_transport_template) {
> +		fc_remote_port_delete(stor_device->rport);
>  		fc_remove_host(host);
> +	}
>  #endif
>  	scsi_remove_host(host);
>  	storvsc_dev_remove(dev);
> --
> 2.5.0