Don't use cmd->request->nr_hw_segments as it may not be initialized
(SG_IO in particular bypasses anything that initializes this and just
uses scsi_do_req to insert a scsi_request directly on the head of the
queue) and a bogus value here can trip up the checks to make sure that
the number of segments will fit in the queue ring buffer, resulting in
commands that are never completed.
Fix up several issues with PCI DMA mapping and failure to check return
values on the mappings.
Make the check for space in the ring buffer happen after the DMA mapping
is done since any checks done before the mapping has taken place are
bogus.
Doug Ledford <dledford@redhat.com>.
Signed-off-by: Andrew Vasquez <andrew.vasquez@qlogic.com>
Signed-off-by: James Bottomley <James.Bottomley@SteelEye.com>
83021920e7