Hi Bart,

On 29/06/22 12:01, Michael Schmitz wrote:

quoted

An example of a user space application that passes an SG I/O data 
buffer to the kernel that is aligned to a four byte boundary but not 
to an eight byte boundary if the -s (scattered) command line option 
is used: 
https://github.com/osandov/blktests/blob/master/src/discontiguous-io.cpp

Thanks - four byte alignment actually wouldn't be an issue for me. 
It's two byte or smaller that would trip up the SCSI DMA.

While I'm sure such an even more pathological test case could be 
written, I was rather worried about st.c and sr.c input ...

Nevermind - I just see m68k defines ARCH_DMA_MINALIGN to be four bytes. 
Should be safe for all that matters, then.

Cheers,

     Michael