Re: [PATCH v1 10/13] IB/iser: Support T10-PI operations

[Mike Christie <michaelc@cs.wisc.edu>]

On 02/27/2014 05:13 AM, Sagi Grimberg wrote:
> diff --git a/drivers/infiniband/ulp/iser/iser_initiator.c b/drivers/infiniband/ulp/iser/iser_initiator.c
> index 58e14c7..7fd95fe 100644
> --- a/drivers/infiniband/ulp/iser/iser_initiator.c
> +++ b/drivers/infiniband/ulp/iser/iser_initiator.c
> @@ -62,6 +62,17 @@ static int iser_prepare_read_cmd(struct iscsi_task *task,
>  	if (err)
>  		return err;
>  
> +	if (scsi_prot_sg_count(iser_task->sc)) {
> +		struct iser_data_buf *pbuf_in = &iser_task->prot[ISER_DIR_IN];
> +
> +		err = iser_dma_map_task_data(iser_task,
> +					     pbuf_in,
> +					     ISER_DIR_IN,
> +					     DMA_FROM_DEVICE);
> +		if (err)
> +			return err;
> +	}
> +
>  	if (edtl > iser_task->data[ISER_DIR_IN].data_len) {
>  		iser_err("Total data length: %ld, less than EDTL: "
>  			 "%d, in READ cmd BHS itt: %d, conn: 0x%p\n",
> @@ -113,6 +124,17 @@ iser_prepare_write_cmd(struct iscsi_task *task,
>  	if (err)
>  		return err;
>  
> +	if (scsi_prot_sg_count(iser_task->sc)) {
> +		struct iser_data_buf *pbuf_out = &iser_task->prot[ISER_DIR_OUT];
> +
> +		err = iser_dma_map_task_data(iser_task,
> +					     pbuf_out,
> +					     ISER_DIR_OUT,
> +					     DMA_TO_DEVICE);
> +		if (err)
> +			return err;
> +	}
> +


The xmit_task callout does handle failures like EINVAL. If the above map
calls fail then you would get infinite retries. You would currently want
to do the mapping in the init_task callout instead.

If it makes it easier on the driver implementation then it is ok to
modify the xmit_task callers so that they handle multiple error codes
for drivers like iser that have the xmit_task callout called from
iscsi_queuecommand.