Re: [ECOS] Re: Does ethernet driver "deliver" method need to be re-entrant?

[Gary Thomas <gary at mlbassoc dot com>]

Grant Edwards wrote:
> On 2007-04-01, Grant Edwards <grante@visi.com> wrote:
>
> > I'm having intermittent problems with an Ethernet driver.  One
> > possible explanation would be if the driver's "deliver" method
> > was being called "simultaneously" from two different contexts.
> >
> > Can this happen, or are calls to deliver guaranteed to be
> > serialized?
>
> The problem caused by a race condition in a different section
> of the driver.  I'm not sure why the author of the driver
> didn't put in mutexes.  The sample driver we gave him to follow
> had them.
>
> Anywy, I still need to know if deliver needs to be re-entrant
> or not.  It looks to me like not -- it is called only from a
> DSR context by an alarm handler in the stack, right?
>
> It would be nice if the driver API documentation state whether
> each driver method needed to be re-entrant or not...

There is no expectation for any of the ethernet driver functions
to be reentrant.  Serialization is handled by the other layers
that call these functions.


--
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Gary Thomas                 |  Consulting for the
MLB Associates              |    Embedded world
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