On spin_lock_irq_save and disabling specific interrupts.

[mind entropy]

Hi,

 When I do spin_lock_irq it disables IRQ's which were enabled. What is
the reason for disabling all the irq's rather than disabling the
specific IRQ line which shares the resource? Wouldn't this be more
efficient and would not lose any interrupts especially if I have a
critical sensor ADC?

Thanks,
Gautam.