Re: [PATCH 4/6] ibmvfc: add FC payload retrieval routines for versioned vfcFrames

Brian King
2020-11-17T22:31:49Z

On 11/11/20 7:04 PM, Tyrel Datwyler wrote:
> The FC iu and response payloads are located at different offsets
> depending on the ibmvfc_cmd version. This is a result of the version 2
> vfcFrame definition adding an extra 64bytes of reserved space to the
> structure prior to the payloads.
>
> Add helper routines to determine the current vfcFrame version and
> returning pointers to the proper iu or response structures within that
> ibmvfc_cmd.
>
> Signed-off-by: Tyrel Datwyler <tyreld@linux.ibm.com>
> ---
> drivers/scsi/ibmvscsi/ibmvfc.c | 76 ++++++++++++++++++++++++----------
> 1 file changed, 53 insertions(+), 23 deletions(-)
>
> diff --git a/drivers/scsi/ibmvscsi/ibmvfc.c b/drivers/scsi/ibmvscsi/ibmvfc.c
> index aa3445bec42c..5e666f7c9266 100644
> --- a/drivers/scsi/ibmvscsi/ibmvfc.c
> +++ b/drivers/scsi/ibmvscsi/ibmvfc.c
> @@ -138,6 +138,22 @@ static void ibmvfc_tgt_move_login(struct ibmvfc_target *);
>
> static const char *unknown_error = "unknown error";
>
> +static struct ibmvfc_fcp_cmd_iu *ibmvfc_get_fcp_iu(struct ibmvfc_host *vhost, struct ibmvfc_cmd *vfc_cmd)
> +{
> + if (be64_to_cpu(vhost->login_buf->resp.capabilities) & IBMVFC_HANDLE_VF_WWPN)

Suggest adding a flag to the vhost structure that you setup after login in order to
simplify this check and avoid chasing multiple pointers along with a byte swap.

Maybe something like:

vhost->is_v2

> + return &vfc_cmd->v2.iu;
> + else
> + return &vfc_cmd->v1.iu;
> +}
> +
> +static struct ibmvfc_fcp_rsp *ibmvfc_get_fcp_rsp(struct ibmvfc_host *vhost, struct ibmvfc_cmd *vfc_cmd)
> +{
> + if (be64_to_cpu(vhost->login_buf->resp.capabilities) & IBMVFC_HANDLE_VF_WWPN)

Same here

> + return &vfc_cmd->v2.rsp;
> + else
> + return &vfc_cmd->v1.rsp;
> +}
> +
> #ifdef CONFIG_SCSI_IBMVFC_TRACE
> /**
> * ibmvfc_trc_start - Log a start trace entry

--
Brian King
Power Linux I/O
IBM Linux Technology Center