Re: [PATCH 3/3] ses: Retry Power-on-reset check condition

[James Bottomley <James.Bottomley@HansenPartnership.com>]

On Thu, 2017-12-21 at 12:22 +0100, Hannes Reinecke wrote:
> During startup any SCSI request might encounter a 'Power-on/reset'
> sense code, which just can be retried.
> In the case of ses it needs to be retried, otherwise ses will
> errorneously detect this as a failure and not attach the driver.
> 
> Signed-off-by: Hannes Reinecke <hare@suse.com>
> ---
>  drivers/scsi/ses.c | 14 ++++++++++----
>  1 file changed, 10 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/scsi/ses.c b/drivers/scsi/ses.c
> index c1f96b0..9c8b3db 100644
> --- a/drivers/scsi/ses.c
> +++ b/drivers/scsi/ses.c
> @@ -110,14 +110,20 @@ static int ses_recv_diag(struct scsi_device
> *sdev, int page_code,
>  		0
>  	};
>  	unsigned char recv_page_code;
> +	int retries = SES_RETRIES;
>  	struct scsi_sense_hdr sshdr;
>  
> +retry:
>  	ret =  scsi_execute_req(sdev, cmd, DMA_FROM_DEVICE, buf,
> bufflen,
> -				&sshdr, SES_TIMEOUT, SES_RETRIES,
> NULL);
> +				&sshdr, SES_TIMEOUT, retries, NULL);
>  	if (unlikely(ret)) {
> -		if (status_byte(ret) == CHECK_CONDITION &&
> -		    sshdr.asc == 0x25 && sshdr.ascq == 0x00) {
> -			ret = -ENODEV;
> +		if (status_byte(ret) == CHECK_CONDITION) {
> +			if (sshdr.asc == 0x29) {
> +				retries--;

Nothing ever checks this, meaning the loop potentially never
terminates.

We already have two templates for how to do this in sd.c ... on the
other hand I can't see any use of scsi_execute/scsi_execute_req that
actually want to see the ASC 29 conditions, so it might be better to
integrate it into scsi_execute().

James