local_irq_save vs raw_local_irq_save

Hi, Please let me know the difference between local_irq_save and raw_local_irq_save ? At which situation one should use raw_local_irq_save? Also, I read "flags" is where interrupt state is saved while disabling interrupts in local cpu (for local_irq_save). What EXACTLY this flags contains? What do you mean by interrupt state here? Thanks! Kavi