CAM rescanner thread?

Scott Long scottl at
Fri Jan 5 10:27:48 PST 2007

Scott Long wrote:
> mjacob at wrote:
>> On Fri, 5 Jan 2007, Scott Long wrote:
>>> mjacob at wrote:
>>>> Opinions? Seems to do what *I* want for automatically attaching 
>>>> devices for mpt or isp when they appear on the fabric. All you have 
>>>> to do is
>>>> alloc a ccb && a path and call xpt_rescan.
>>> Why do you need a separate thread for this?  Many other drivers 
>>> already handle this just fine.
>> In CAM?
>> I did try doing it without a thread and had all sorts of problems that 
>> led to panics. I suppose I could try and fix that, but it's also true 
>> that notification that things have changed is almost certainly on an 
>> ithread and that the begin of a scan starts a heck of a lot of work 
>> before returning.
>> D'ya think it's that crucial other than just another proc slot?
>> -matt
> Ok, I see what you're saying.  What I think needs to ultimately happen 
> is for the entire probe code to go into a thread.  I've tried this a
> couple of times, but have been caught up in trying to separate out the
> SPI and non-SPI bits of it.  Your patch is looks to be a good start at
> the more simple approach.
> Scott

Oh, one more thing.  Instead of it being a new XPT API function, could 
it be an async op with an appropriate handler in the XPT?  Heck, maybe
this is exactly how you 'fix' AC_FOUND_DEVICE to DTRT.


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