why use spin_lock_{irq, irqsave}()

[अनुज]

Hi list

Please anybody elaborate on this point : When we take any lock in
kernel e.g. spin_lock() then preemption is automatically disabled by
kernel. Then why to use spin_lock_{irq, irqsave}()? I am assuming even
interrupt handler cant preempt the kernel when preemption is disabled
by kernel.


Thanks,

Regards

-- 
Anuj Aggarwal

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