>I suspect that chaining of events should be built on top of the
>primatives, which should be kept as simple as possible. Comments?
Do the following modifications to your wait queue extension sound
1. Change add_wait_queue to add elements to the end of queue (fifo, by
default) and instead have an add_wait_queue_lifo() routine that adds to the
head of the queue ?
[This will help avoid the problem of waiters getting woken up before LIFO
wakeup functions have run, just because the wait happened to have been
issued after the LIFO callbacks were registered, for example, while an IO
is going on]
Or is there a reason why add_wait_queue adds elements to the head by
2. Pass the wait_queue_head pointer as a parameter to the wakeup function
(in addition to wait queue entry pointer).
[This will make it easier for the wakeup function to access the structure
in which the wait queue is embedded, i.e. the object which the wait queue
is associated with. Without this, we might have to store a pointer to this
object in each element linked in the wait queue. This never was a problem
with sleeping waiters because the a reference to the object being waited
for would have been on the waiter's stack/context, but with wakeup
functions there is no such context]
3. Have __wake_up_common break out of the loop if the wakeup function
returns 1 (or some other value) ?
[This makes it possible to abort the loop based on conditional logic in the
wakeup function ]
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