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Date: Tue, 12 Oct 2004 15:30:06 -0700 (PDT)
From: Don Lewis <truckman@FreeBSD.org>
To: alfred@FreeBSD.org
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Subject: Re: cvs commit: src/sys/kern kern_subr.c
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On 12 Oct, Alfred Perlstein wrote:
> * Don Lewis <truckman@FreeBSD.org> [041012 15:17] wrote:
>> On 12 Oct, Alfred Perlstein wrote:
>> > I like this, my only concern is that there may be places that
>> > call this with locks held but with the kernel/user buffer wired
>> > so that it can't fault.
>> > 
>> > Are you sure this isn't the case?  (specifically for some sysctls)
>> 
>> There are a number of sysctl handlers where I added code to wire the
>> buffer so that there was no danger of sleeping while a mutex is held.
>> Allocating a kernel buffer and doing an extra copy would be ugly.
> 
> Yup.  Maybe an auxilliary uio_move_wired() that doesn't do this
> check?

As I mentioned in my followup message, the sysctl handlers don't use
uiomove().  This might be a good idea for copyin() and copyout(), where
the _wired versions would check to see if the memory was actually wired.