fix offset by one

Signed-off-by: Peter Lieven <pl@kamp.de>
add trivial check in buffer is zero

Signed-off-by: Peter Lieven <pl@kamp.de>
dup_page -> zero_page

Signed-off-by: Peter Lieven <pl@kamp.de>
fix add trivial check in buffer is zero

Signed-off-by: Peter Lieven <pl@kamp.de>
fix descr + trivial for buffer_find_nonzero_offset

Signed-off-by: Peter Lieven <pl@kamp.de>
buffer_find_nonzero_offset unroll factor

Signed-off-by: Peter Lieven <pl@kamp.de>
do send zero page in ram bulk stage

Signed-off-by: Peter Lieven <pl@kamp.de>