xen-blkfront: correct maximum segment accounting
Making use of "max_indirect_segments=" has issues:
- blkfront_setup_indirect() may end up with zero psegs when PAGE_SIZE
is sufficiently much larger than XEN_PAGE_SIZE
- the variable driven by the command line option
(xen_blkif_max_segments) has a somewhat different purpose, and hence
should namely never end up being zero
- as long as the specified value is lower than the legacy default,
we better don't use indirect segments at all (or we'd in fact lower
throughput)
Signed-off-by: Jan Beulich <jbeulich@suse.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
1 file changed