Re: [PATCH 4.19 59/92] sd: Fix REQ_OP_ZONE_REPORT completion handling

[Pavel Machek]

Hi!

> From: Masato Suzuki <masato.suzuki@xxxxxxx>
> 
>

> ZBC/ZAC report zones command may return less bytes than requested if the
> number of matching zones for the report request is small. However, unlike
> read or write commands, the remainder of incomplete report zones commands
> cannot be automatically requested by the block layer: the start sector of
> the next report cannot be known, and the report reply may not be 512B
> aligned for SAS drives (a report zone reply size is always a multiple of
> 64B). The regular request completion code executing bio_advance() and
> restart of the command remainder part currently causes invalid zone
> descriptor data to be reported to the caller if the report zone size is
> smaller than 512B (a case that can happen easily for a report of the last
> zones of a SAS drive for example).

What is the story here? Mainline does not seem to have this patch, so
this is not the case of "upstream commit xxx" line simply missing. If
the same bug is fixed in mainline different way, it would be nice to
point to that commit..

Mainline does not handle REQ_OP_ZONE_REPORT in sd.c at all..

Best regards,
								Pavel


> +++ b/drivers/scsi/sd.c
> @@ -1969,9 +1969,13 @@ static int sd_done(struct scsi_cmnd *SCp
>  		}
>  		break;
>  	case REQ_OP_ZONE_REPORT:
> +		/* To avoid that the block layer performs an incorrect
> +		 * bio_advance() call and restart of the remainder of
> +		 * incomplete report zone BIOs, always indicate a full
> +		 * completion of REQ_OP_ZONE_REPORT.
> +		 */
>  		if (!result) {
> -			good_bytes = scsi_bufflen(SCpnt)
> -				- scsi_get_resid(SCpnt);
> +			good_bytes = scsi_bufflen(SCpnt);
>  			scsi_set_resid(SCpnt, 0);
>  		} else {
>  			good_bytes = 0;
> 

-- 
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html

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