>> > sem->count sem->waking
>> >No process holds the semaphore 1 0
>> >Process A acquires the semaphore 0 0
>> >Process B calls down_interruptible() -1 0
>> >Process B is interrupted and passes
>> > waking_non_zero() -1 0
>> >Process A calls up() (on another CPU) 0 1
>>
>> B get wakenup and runs waking_non_zero that sees sem->waking == 1 and so
>> do sem->waking-- and then B has no way to runs atomic_inc() because
>> waking_non_zero returned 1 (owned the semaphore).
>
>If B runs waking_non_zero before A calls up, it will see sem->waking == 0.
So? If B runs waking_non_zero (called by __down_interruptible()) at the
time sem->waking is 0, it will go to sleep in schedule() and will do
nothing.
If insted __down_interruptible() will se a signal pending it will simply
undo the decl() done inside __inline__ down().
Can you explain better your point?
Andrea Arcangeli
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