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

From: Greg Kroah-Hartman
Date: Tue Jan 28 2020 - 13:15:17 EST


On Tue, Jan 28, 2020 at 07:02:31PM +0100, Pavel Machek wrote:
> 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..

Yes, this is not needed in 5.4 as it was rewritten differently there.

thanks,

greg k-h