using fast interrupts with em(4)

[M. Warner Losh]

In message: <20050930010434.67727.qmail at web35003.mail.mud.yahoo.com>
            Kernel Dev <kerndev at yahoo.com> writes:
: Hello All. For a project, I am looking into making the em(4) driver use fast interrupts. Has someone done this or are there other driver references that could help me in this?
:  
: I understand that the main problems are:
:  
: 1. Sharing of interrupts.
: 2. Blocking (memory and mutexes).
:  
: Are there any other issues I might have missed?

You can share fast interrupts, but it isn't a good idea...

You can't block in a fast interrupt.  You must use spin locks.  You
cannot call anything that will sleep in a fast interrupt.  Ideally,
you'd not modify anything that isn't covered by your own spin locks,
leaving that for a taskqueue or similar queueing strategy.

Warner