On Wed, 21 Nov 2018, Christoph Hellwig wrote:
> Hi all,
>
> you in the To list maintain or wrote SCSI drivers that set the
> DISABLE_CLUSTERING flag, which basically disable merges of any
> bio segments. We already have the actual max_segment size limit
> to say which length a segment should have, independent of merged
> or originally created, so this limit generally should rarely if
> ever be required, and mostly is an old cut an paste error.
>
Are you referring to
blk_queue_max_segment_size(q, dma_get_max_seg_size(dev));
in drivers/scsi/scsi_lib.c?
Is the segment size limitation of the DMA controller the only reason to
want DISABLE_CLUSTERING?
> Can you go over your drivers and check if it could be removed?
>
Adding Sun 3 maintainer to Cc.
Besides sun3_scsi.c and atari_scsi.c, the SCSI drivers I take an interest
in don't actually use a DMA controller. If my question about DMA
controllers gets a "yes" then I guess I can send a patch for those
drivers.
--
