The SCSI megaraid drive goes to great effort to kmap
the scatterlist buffer (if used), but then uses the
wrong pointer when copying to it afterward.
Signed-off-by:  Mark Lord <lkml@rtr.ca>
Acked by: Ju, Seokmann <Seokmann.Ju@engenio.com>
Signed-off-by: James Bottomley <James.Bottomley@SteelEye.com>
                                        sg->offset;
                        } else
                                buf = cmd->request_buffer;
-                       memset(cmd->request_buffer, 0, cmd->cmnd[4]);
+                       memset(buf, 0, cmd->cmnd[4]);
                        if (cmd->use_sg) {
                                struct scatterlist *sg;