Messages in this thread | | | Date | Sun, 05 Feb 2006 13:59:31 +0100 | From | Stefan Richter <> | Subject | Re: [RFC 4/4] firewire: add mem1394 |
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Johannes Berg wrote: > On Fri, 2006-02-03 at 12:35 +0100, Andy Wingo wrote: >>On Thu, 2006-02-02 at 23:43 +0100, Johannes Berg wrote: >> >>>+ spin_lock(&dev_list_lock); >> >>Stupid question: are you sure that something coming from an interrupt >>handler won't try to grab this lock? For example from a cable unplug? > > Yes, I'm pretty sure (but I hope some of the firewire experts will chime > in) -- but if you unplug or anything the node only goes into 'limbo' and > afaict if it is ever cleaned up then that comes from a thread context.
The lock will only be taken in non-atomic context. In particular, if a mem1394 device is to be removed after cable unplug, the code will be run by knodemgrd.
What is more recommendable for mutual exclusion in non-atomic context (here also with very low probality of lock contention, given the current implementation of ieee1394) --- a mutex or a spinlock? -- Stefan Richter -=====-=-==- --=- --=-= http://arcgraph.de/sr/ - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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