[linux-dvb] Re: [PATCH] support for multiple feeds per pid

[Emard <emard@softhome.net>]

> you must not use semaphores but spinlocks for locking data accessed from 
> irq handlers. Places where lists are altered have to use irq safe 
> spinlocks, which switch off interrupts while the lists are modified.
> 
> All the other code can use readonly spinlocks. In any case you want to 
> keep this locking as fine-grained as possible.
> 
> Holger

There's down_interruptible(demux->mutex), being called from
ioctl over several functions before it updates the list.

OK, maybe this down_interruptible should be the spinlock.

It will disable interrupts. Besides of disabling them, I think
it has to also wait for e.g. vpeirq() to finish.

Is this wait_for_vpeirq() finish being done automatically
by the spinlock or should we after the spinlock additionaly
wait for vpeirq to finish ?

Emard


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