Re: [PATCH v4 1/2] scsi: Add intermediate STARGET_REMOVE state to scsi_target_state

From: Johannes Thumshirn
Date: Wed Apr 13 2016 - 04:19:58 EST


Hi Xiong
Sorry for the late reply

On Dienstag, 12. April 2016 21:01:53 CEST Xiong Zhou wrote:
> How about this?
>
> drivers/scsi/scsi_scan: mark STARGET_REMOVE state before destroy
>
> Signed-off-by: Xiong Zhou <jencce.kernel@xxxxxxxxx>
> ---
> drivers/scsi/scsi_scan.c | 3 +++
> 1 file changed, 3 insertions(+)
>
> diff --git a/drivers/scsi/scsi_scan.c b/drivers/scsi/scsi_scan.c
> index 27df7e7..21092e5 100644
> --- a/drivers/scsi/scsi_scan.c
> +++ b/drivers/scsi/scsi_scan.c
> @@ -395,6 +395,8 @@ static void scsi_target_reap_ref_release(struct kref *kref)
> transport_remove_device(&starget->dev);
> device_del(&starget->dev);
> }
> +
> + starget->state = STARGET_REMOVE;
> scsi_target_destroy(starget);
> }

The only scsi_target_reap_ref_release() caller is scsi_target_reap_ref_put(),
which in turn is only called by scsi_target_reap(). scsi_target_reap()'s only
callers are scsi_remove_target()/__scsi_remove_target(), which set the
STARGET_REMOVE state and

__scsi_add_device()
scsi_get_host_dev()
__scsi_scan_target()

Which I'm currently investiganting (in parallel to reproducing the bug).

>
> @@ -465,6 +467,7 @@ static struct scsi_target
> *scsi_alloc_target(struct device *parent,
> dev_printk(KERN_ERR, dev, "target allocation failed, error %d\n", error);
> /* don't want scsi_target_reap to do the final
> * put because it will be under the host lock */
> + starget->state = STARGET_REMOVE;
> scsi_target_destroy(starget);
> return NULL;
> }

Here starget->state is STARGET_CREATED and the assertion is already aware of
this state transitoin. IOTW this /shouldn't/ be needed.


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Johannes Thumshirn Storage
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