The calculation of nr_pages in scsi_req_map_sg() doesn't account for
the fact that the first page could have an offset that pushes the end
of the buffer onto a new page.
Signed-off-by: NBryan Holty <lgeek@frontiernet.net>
Signed-off-by: NJames Bottomley <James.Bottomley@SteelEye.com>