On Thu, Nov 22, 2018 at 10:11:33AM +1300, Michael Schmitz wrote: > Christoph, > for Atari SCSI, commands can only be merged if the physical addresses > of all buffers are contiguous (limitation of the Falcon DMA engine). > Documentation/scsi/scsi_mid_low_api.tx does not spell out whether that > is the case. > > Atari SCSI disables scatter/gather, so if that's sufficient to cue > midlevel or bio to not undertake any merging, the flag is no longer > needed.
Yes, if scatter/gather is disable (sg_tablesize == 1 or 0), there will just be a single, contiguos segment up to .max_sectors, which might straddle a page boundary if it is larger than PAGE_SIZE. If that is ok for the ata SCSI hardware we can remove the DISABLE_CLUSTERING setting.
