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Confusion regarding spin_lock_irqsave and spin_unlock_irqrestore.

Hi,

A very newbie question on locking.

LDD3 talks about spin_lock_irqsave and spin_unlock_restore  and
mentions that the two _must_ be called from the same function or the
code might break on some architecture. I searched for this on google
and found that one of the platform on which it can break is sparc.

However in the implementation of timers (kernel/timer.c) in the
function __mod_timer the spin_lock_irqsave and spin_unlock_restore are
being called from different functions. Of course the flag variable
used is same in both cases but this differs from what I have read.
So how does this work ? I am using 2.6.15.7 and 2.6.17.3 kernel.

-
Regards,
Ranjan

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