nr_pages calculation in scsi_req_map_sg()

["Jan Beulich" <jbeulich@novell.com>]

James,

while reviewing code derived from that function I found this calculation
to be suspicious: I would think that it should get it wrong when both
start and end of the buffer area are misaligned (e.g. consider the case
where sgl->offset equals PAGE_SIZE-1 and bufflen equals 2 - the result
would be 1 when it should have been 2).
Is there something preventing this from happening?

Thanks, Jan