[ofa-general] question regarding umad_recv

[Hal Rosenstock]

On Mon, 2007-10-15 at 17:06 +0200, Sasha Khapyorsky wrote:
> On 07:38 Mon 15 Oct     , Hal Rosenstock wrote:
> > Hi Sasha,
> > 
> > On Mon, 2007-10-15 at 15:54 +0200, Sasha Khapyorsky wrote:
> > > Hi Hal,
> > > 
> > > On 06:18 Mon 15 Oct     , Hal Rosenstock wrote:
> > > > 
> > > > I don't recall as this is from a very very long time ago but in looking
> > > > at this, I agree with your assessment that it can be simplified (and
> > > > there appears to be no real need for what is contained in struct Port
> > > > other than the fd). The only downside I see is the subtle change in the
> > > > public umad_ APIs changing int portid -> int fd.
> > > 
> > > There is no API change at all - umad_open_port() still return unique
> > > integer descriptor as it was before. Here we are only changing
> > > undocumented (at least I'm not able to find any public description about
> > > what umad_open_port() should return) behavior of this API (by replacing
> > > mad device number as umad_open_port() return value, 
> > 
> > It's all the other APIs which say umad_xxx(int portid, ...) are now
> > umad_xxxx(int fd, ...). A subtle change.
> 
> I changed this only in umad.c files (to make it clear for internal
> implementation reviewers) and saved it as 'portid' in the header where
> API is described - an user should not care what internal meaning of
> portid is. For getting fd explicitly there is umad_get_fd(portid)
> method.

Which could be eliminated as redundant; not sure anything is using this
API.
 
> > > but if we want to
> > > support multiple open()s there is no choice - device number is not
> > > suitable for this).
> > 
> > Understood.
> > 
> > > > I suppose all the tools
> > > > would continue to work without change here even if libibumad were
> > > > changed underneath it, right ?
> > > 
> > > Right.
> > > 
> > > > BTW, when you do this, the umad man pages
> > > > should all be updated for this change.
> > > 
> > > I see only that umad_open_port.3 should be fixed - it says that return
> > > value is "0" on success, which is not correct anyway. Not really related
> > > to the patch. Do you see another places to fix in man?
> > 
> > Don't a number of them indicate int portid as an input parameter (and
> > this should now be int fd) ? Just grep for portid in those man pages...
> 
> Don't think we want to make the internal in its nature "portid = fd
> feature" to be part of the public API. 'portid' is fine IMO because it
> doesn't mean a lot - just "0 or an unique positive value...", pretty
> suitable for public API.

portid gives a level of abstraction but is it needed ? If we were
starting today, would you say the same thing ?

-- Hal

> Sasha
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