[ACPI] RE: [PATCH 1/2] make acpi_path_name() global

[Moore, R. <rob...@in...>]

That is correct, all ACPICA interfaces that require a buffer parameter
allow the buffer object to be pre-initialized with a buffer allocated by
the caller or allow ACPICA to allocate the buffer.

Bob


> -----Original Message-----
> From: Rolf Eike Beer [mailto:ei...@sf...]
> Sent: Friday, December 16, 2005 1:04 PM
> To: Accardi, Kristen C
> Cc: Randy.Dunlap; Brown, Len; ran...@li...; acpi-
> de...@li...; pci...@li...;
> gr...@su...; Moore, Robert
> Subject: Re: [PATCH 1/2] make acpi_path_name() global
>=20
> > On Thu, 2005-12-15 at 21:27 -0800, Randy.Dunlap wrote:
> >> On Thu, 15 Dec 2005 23:56:47 -0500 Brown, Len wrote:
> >
> > <snip>
> >> > an example of this is acpi_get_name(), which as declared
> >> > isn't supposed to be available outside the core.
> >> > All the uses of it to print ACPI namespace tokens in /proc
> >> > are totally bogus and should be deleted.  The other use
> >> > of it is to print out debug strings -- stuff the OS
> >> > doesn't really need to "know" and maybe something the
> >> > core should do for it.  That leaves the hotplug use,
> >> > which I don't understand.  What does SATA need
> >> > with the actual path names?
> >>
> >> SATA uses the name string for (a) debugging, as you have
> >> mentioned, and (b) for comparing complete device strings
> >> to match/find a SATA _ADR under a device (in a device's
> >> scope).  I can do without (a) as well as the rest of the
> >> kernel can, of course.  I don't know how to find and match
> >> SATA devices (part b) without it, so this is an opportunity
> >> for you to educate me.  :)
> >>
> >>
> > We use this in pciehp and shpchp as well for the same reason.  One
thing
> > I don't love about these patches is the need now to worry about
freeing
> > memory after you make these calls.  To me that seems like asking for
> > memory leaks in error paths at some point down the road when someone
> > less careful than Randy adds some code in.  If there were some way
to
> > return a pointer to a static string, I'd prefer that solution, but I
> > can't figure out from looking at the acpi code if that is possible.
If
> > there's some better way to perform this compare, I'd like to hear it
> > too.
>=20
> Don't do the allocation in the function but pass a buffer and it's
length
> to it. The caller can do dynamic allocation if needed or use a buffer
on
> stack if not. This also makes error handling easier as ENOMEM can't
happen
> in acpi_path_name() anymore.
>=20
> Eike