How is supposed to be protected the units list?
scottl at samsco.org
Sun Mar 21 16:20:25 UTC 2010
On Mar 21, 2010, at 10:02 AM, Attilio Rao wrote:
> 2010/3/21 Alexander Motin <mav at freebsd.org>:
>> Attilio Rao wrote:
>>> So I made this new patch using the bus lock:
>> OK. I've looked on both and I think both have race window between unit
>> number allocation and insertion into the list. I've changed last patch
>> to not drop the lock in meantime. What do you think about this:
>> Part about scsi_da.c I don't like in both cases, as I am not sure that
>> locks can't be recursed there in case of some errors. I don't see how
>> adding second lock could solve it.
> I think that we should protect there in anyway.
> Probabilly we may cache the list and refcount the periphs? (then
> unlock the lock and just do the lockless operation in order to avoid
> The race handling for units allocation is fine, thanks.
Please give me a few more days to review and comment on this. Alexander's change is very invasive in that it re-orders operations, and I'd like to review it to ensure that that doesn't break existing ordering assumptions.
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