Re: [PATCH 1/2] scsi_transport_fc: FC pass through support - revised II

[Boaz Harrosh <bharrosh@panasas.com>]

Seokmann Ju wrote:
>  From f32b386a61a23f408974f2289cd34200f59401e1 Mon Sep 17 00:00:00 2001
> From: root <root@linux-atl-00.qlogic.com>
> Date: Tue, 28 Oct 2008 19:27:15 -0700
> Subject: [PATCH] scsi_transport_fc: FC pass through support
> 
> This patch will add FC pass through support.
> The FC pass through support is service request handling mechanism
> for FC specification defined services including,
> - Link Services (Basic LS, Extended LS)
> - Generic Services (FC-CT - Common Transport)
> The support utilize BSG (Block layer SCSI Generic) interface with
> bidi (bi-directional) nature in handling the service requests.
> 
> This patch added following featues in the support
> - FC service structure has defined to transport service requests
> - Handles the service request in asynchronous manner - LLD
> - Timeout capability
> - Abort capability
> 
> Signed-off-by: Seokmann Ju <seokmann.ju@qlogic.com>
> ---
>   drivers/scsi/scsi_transport_fc.c |  216 +++++++++++++++++++++++++++++ 
> ++++++++-
>   include/scsi/scsi_transport_fc.h |   81 ++++++++++++++-
>   2 files changed, 294 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/scsi/scsi_transport_fc.c b/drivers/scsi/ 
> scsi_transport_fc.c
> index 1e71abf..e26e8e0 100644
> --- a/drivers/scsi/scsi_transport_fc.c
> +++ b/drivers/scsi/scsi_transport_fc.c
> @@ -43,6 +43,11 @@ static void fc_vport_sched_delete(struct  
> work_struct *work);
>   static int fc_vport_setup(struct Scsi_Host *shost, int channel,
>   	struct device *pdev, struct fc_vport_identifiers  *ids,
>   	struct fc_vport **vport);
> +static enum blk_eh_timer_return fc_service_timeout(struct request  
> *req);
> +static void fc_service_done(struct fc_service *);
> +static int fc_service_handler(struct Scsi_Host *, struct fc_rport *,
> +    struct request *, struct request_queue *);
> +static void fc_bsg_remove(struct Scsi_Host *, struct fc_rport *);
> 
>   /*
>    * Redefine so that we can have same named attributes in the
> @@ -2413,11 +2418,218 @@ fc_rport_final_delete(struct work_struct *work)
> 
>   	transport_remove_device(dev);
>   	device_del(dev);
> +	fc_bsg_remove(shost, rport);
>   	transport_destroy_device(dev);
>   	put_device(&shost->shost_gendev);	/* for fc_host->rport list */
>   	put_device(dev);			/* for self-reference */
>   }
> 
> +static enum blk_eh_timer_return fc_service_timeout(struct request *req)
> +{
> +	struct fc_service *service = (void *) req->special;
> +	struct Scsi_Host *shost = rport_to_shost(service->rport);
> +	struct fc_internal *i = to_fc_internal(shost->transportt);
> +	unsigned long flags;
> +	int res = 0;
> +
> +	if (service->rport->port_state == FC_PORTSTATE_BLOCKED)
> +		return BLK_EH_RESET_TIMER;
> +
> +	spin_lock_irqsave(&service->service_state_lock, flags);
> +	if (!(service->service_state_flag & FC_SERVICE_STATE_DONE))
> +		service->service_state_flag |= FC_SERVICE_STATE_TIMEOUT;
> +	spin_unlock_irqrestore(&service->service_state_lock, flags);
> +
> +	if (i->f->abort_fc_service)
> +		res = i->f->abort_fc_service(service);
> +
> +	if (res) {
> +		printk(KERN_ERR "ERROR: issuing FC service to the LLD "
> +		"failed with status %d\n", res);
> +		fc_service_done(service);
> +	}
> +
> +	/* the blk_end_sync_io() doesn't check the error */
> +	return BLK_EH_NOT_HANDLED;
> +}
> +
> +static void fc_service_done(struct fc_service *service)
> +{
> +
> +	if (service->service_state_flag != FC_SERVICE_STATE_DONE) {
> +		if (service->service_state_flag == FC_SERVICE_STATE_TIMEOUT)
> +			printk(KERN_ERR "ERROR: FC service timed out\n");
> +		else if (service->service_state_flag ==
> +		    FC_SERVICE_STATE_ABORTED)
> +			printk(KERN_ERR "ERROR: FC service aborted\n");
> +		else
> +			printk(KERN_ERR "ERROR: FC service not finished\n");
> +	}
> +
> +	if (service->srv_reply.status != FC_SERVICE_COMPLETE) {
> +		printk(KERN_ERR "ERROR: FC service to rport %p failed with"
> +		    " status 0x%x\n", service->rport,
> +		    service->srv_reply.status);
> +	}
> +
> +	service->req->errors = service->srv_reply.status;
> +	service->req->next_rq->errors = service->srv_reply.status;
> +

Just nit-picking. next_rq should not carry any other information but
BIOs (sg-lists) and residual. Any global state information is carried
on the main request only.
-	service->req->next_rq->errors = service->srv_reply.status;

Jens TOMO?

I never understood the difference please explain:
What is the difference between "req->errors =" and the error passed
into blk_end_xxx_request(req, error,...)?

> +	blk_end_bidi_request(service->req, service->srv_reply.status,
> +	    blk_rq_bytes(service->req),
> +	    service->req->next_rq ? blk_rq_bytes(service->req->next_rq) : 0);
> +
> +	kfree(service->payload_dma);
> +	kfree(service->response_dma);
> +	kfree(service);
> +}
> +
<snip>

Thanks
Boaz