Re: [PATCH 14/24] libsas: prevent double completion of scmds from eh

[Sergei Shtylyov <sshtylyov@mvista.com>]

Hello.

On 17-12-2011 6:34, Dan Williams wrote:

> We invoke task->task_done() to free the task in the eh case, but at this
> point we are prepared for scsi_eh_flush_done_q() to finish off the scmd.

> Introduce sas_end_task() to capture the final response status from the
> lldd and free the task.

> Also take the opportunity to kill this warning.
> drivers/scsi/libsas/sas_scsi_host.c: In function ‘sas_end_task’:
> drivers/scsi/libsas/sas_scsi_host.c:102:3: warning: case value ‘2’ not in enumerated type ‘enum exec_status’ [-Wswitch]

> Signed-off-by: Dan Williams <dan.j.williams@intel.com>
> ---
>   drivers/scsi/libsas/sas_scsi_host.c |   61 +++++++++++++++++++----------------
>   include/scsi/libsas.h               |    5 ++-
>   2 files changed, 37 insertions(+), 29 deletions(-)

> diff --git a/drivers/scsi/libsas/sas_scsi_host.c b/drivers/scsi/libsas/sas_scsi_host.c
> index f32c628..13aee61 100644
> --- a/drivers/scsi/libsas/sas_scsi_host.c
> +++ b/drivers/scsi/libsas/sas_scsi_host.c
> @@ -49,27 +49,12 @@
>   #include<linux/scatterlist.h>
>   #include<linux/libata.h>
>
> -/* ---------- SCSI Host glue ---------- */
> -
> -static void sas_scsi_task_done(struct sas_task *task)
> +/* record final status and free the task */
> +static void sas_end_task(struct scsi_cmnd *sc, struct sas_task *task)
>   {
>   	struct task_status_struct *ts =&task->task_status;
> -	struct scsi_cmnd *sc = task->uldd_task;
>   	int hs = 0, stat = 0;
[...]
> @@ -124,10 +109,32 @@ static void sas_scsi_task_done(struct sas_task *task)
>   			break;
>   		}
>   	}
> -	ASSIGN_SAS_TASK(sc, NULL);
> +
>   	sc->result = (hs<<  16) | stat;
> +	ASSIGN_SAS_TASK(sc, NULL);
>   	list_del_init(&task->list);
>   	sas_free_task(task);
> +}
> +
> +static void sas_scsi_task_done(struct sas_task *task)
> +{
> +	struct scsi_cmnd *sc = task->uldd_task;
> +
> +	if (unlikely(task->task_state_flags&  SAS_TASK_STATE_ABORTED)) {
> +		/* Aborted tasks will be completed by the error handler */
> +		SAS_DPRINTK("task done but aborted\n");
> +		return;
> +	}
> +
> +	if (unlikely(!sc)) {
> +		SAS_DPRINTK("task_done called with non existing SCSI cmnd!\n");
> +		list_del_init(&task->list);
> +		sas_free_task(task);
> +		return;
> +	}
> +
> +	ASSIGN_SAS_TASK(sc, NULL);

    Why do it twice -- once here and then in sas_end_task()?

> +	sas_end_task(sc, task);
>   	sc->scsi_done(sc);
>   }

MBR, Sergei