scheduler/interruption doubt

[glauber@xxxxxxxxxxxxx]

There comes another newbie question for you guys:

I got it while reading the sched.c source file

In the function task_rq_lock(), we can see the 
following code : 

local_irq_save(*flags);
rq = task_rq(p);
spin_lock(&rq->lock);

What happens if a interruption occurs exactly after
local_irq_save() is executed? Wouldn't the state
of flags be changed ? I mean, when spin_lock_irqrestore()
is executed, won't it restore the wrong flags? (obviouly,
in the case that the interrupt occurs) 
After all, what are this code advantages over
some code like:

rq = tasq_rq(p);
spin_lock_irqsave(&rq->lock);
	...
spin_lock_irqrestore(&rq->lock);

???

Any answers is welcome :)


-- 
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