Re: [PATCH 2/8] scsi: target: Add tmr_notify backend function

[Mike Christie <michael.christie@xxxxxxxxxx>]

On 7/10/20 5:48 AM, Bodo Stroesser wrote:
> Target core is modified to call an optional backend
> callback function if a TMR is received or commands
> are aborted implicitly after a PR command was received.
> The backend function takes as parameters the se_dev, the
> type of the TMR, and the list of aborted commands.
> If no commands were aborted, an empty list is supplied.
>
> Signed-off-by: Bodo Stroesser <bstroesser@xxxxxxxxxxxxxx>
> ---
>   drivers/target/target_core_tmr.c       | 16 +++++++++++++++-
>   drivers/target/target_core_transport.c |  1 +
>   include/target/target_core_backend.h   |  2 ++
>   include/target/target_core_base.h      |  1 +
>   4 files changed, 19 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/target/target_core_tmr.c b/drivers/target/target_core_tmr.c
> index b65d7a0a5df1..39d93357db65 100644
> --- a/drivers/target/target_core_tmr.c
> +++ b/drivers/target/target_core_tmr.c
> @@ -116,6 +116,7 @@ void core_tmr_abort_task(
>   	struct se_tmr_req *tmr,
>   	struct se_session *se_sess)
>   {
> +	LIST_HEAD(aborted_list);
>   	struct se_cmd *se_cmd, *next;
>   	unsigned long flags;
>   	bool rc;
> @@ -144,7 +145,7 @@ void core_tmr_abort_task(
>   		if (!rc)
>   			continue;
>   
> -		list_del_init(&se_cmd->state_list);
> +		list_move_tail(&se_cmd->state_list, &aborted_list);
>   		se_cmd->state_active = false;
>   
>   		spin_unlock_irqrestore(&dev->execute_task_lock, flags);
> @@ -157,6 +158,11 @@ void core_tmr_abort_task(
>   			WARN_ON_ONCE(transport_lookup_tmr_lun(tmr->task_cmd) <
>   					0);
>   
> +		if (dev->transport->tmr_notify)
> +			dev->transport->tmr_notify(dev, TMR_ABORT_TASK,
> +						   &aborted_list);
> +
> +		list_del_init(&se_cmd->state_list);
>   		target_put_cmd_and_wait(se_cmd);
>   
>   		printk("ABORT_TASK: Sending TMR_FUNCTION_COMPLETE for"
> @@ -167,6 +173,9 @@ void core_tmr_abort_task(
>   	}
>   	spin_unlock_irqrestore(&dev->execute_task_lock, flags);
>   
> +	if (dev->transport->tmr_notify)
> +		dev->transport->tmr_notify(dev, TMR_ABORT_TASK, &aborted_list);

Is this needed? It seems like the backend can't do anything because 
there isn't enough info.

I saw in tcmu_tmr_notify it looks when then happens we can still do 
queue_tmr_ring, but there would be no commands. Was that intentional?


> +
>   	printk("ABORT_TASK: Sending TMR_TASK_DOES_NOT_EXIST for ref_tag: %lld\n",
>   			tmr->ref_task_tag);
>   	tmr->response = TMR_TASK_DOES_NOT_EXIST;
> @@ -318,6 +327,11 @@ static void core_tmr_drain_state_list(
>   	}
>   	spin_unlock_irqrestore(&dev->execute_task_lock, flags);
>   
> +	if (dev->transport->tmr_notify)
> +		dev->transport->tmr_notify(dev, preempt_and_abort_list ?
> +					   TMR_LUN_RESET_PRO : TMR_LUN_RESET,
> +					   &drain_task_list);
> +
>   	while (!list_empty(&drain_task_list)) {
>   		cmd = list_entry(drain_task_list.next, struct se_cmd, state_list);
>   		list_del_init(&cmd->state_list);
> diff --git a/drivers/target/target_core_transport.c b/drivers/target/target_core_transport.c
> index e6e1fa68de54..9fb0be0aa620 100644
> --- a/drivers/target/target_core_transport.c
> +++ b/drivers/target/target_core_transport.c
> @@ -2946,6 +2946,7 @@ static const char *target_tmf_name(enum tcm_tmreq_table tmf)
>   	case TMR_LUN_RESET:		return "LUN_RESET";
>   	case TMR_TARGET_WARM_RESET:	return "TARGET_WARM_RESET";
>   	case TMR_TARGET_COLD_RESET:	return "TARGET_COLD_RESET";
> +	case TMR_LUN_RESET_PRO:		return "LUN_RESET_PRO";
>   	case TMR_UNKNOWN:		break;
>   	}
>   	return "(?)";
> diff --git a/include/target/target_core_backend.h b/include/target/target_core_backend.h
> index f51452e3b984..6336780d83a7 100644
> --- a/include/target/target_core_backend.h
> +++ b/include/target/target_core_backend.h
> @@ -40,6 +40,8 @@ struct target_backend_ops {
>   	ssize_t (*show_configfs_dev_params)(struct se_device *, char *);
>   
>   	sense_reason_t (*parse_cdb)(struct se_cmd *cmd);
> +	void (*tmr_notify)(struct se_device *se_dev, enum tcm_tmreq_table,
> +			   struct list_head *aborted_cmds);
>   	u32 (*get_device_type)(struct se_device *);
>   	sector_t (*get_blocks)(struct se_device *);
>   	sector_t (*get_alignment_offset_lbas)(struct se_device *);
> diff --git a/include/target/target_core_base.h b/include/target/target_core_base.h
> index 18c3f277b770..549947d407cf 100644
> --- a/include/target/target_core_base.h
> +++ b/include/target/target_core_base.h
> @@ -207,6 +207,7 @@ enum tcm_tmreq_table {
>   	TMR_LUN_RESET		= 5,
>   	TMR_TARGET_WARM_RESET	= 6,
>   	TMR_TARGET_COLD_RESET	= 7,
> +	TMR_LUN_RESET_PRO	= 0x80,
>   	TMR_UNKNOWN		= 0xff,
>   };
>