Re: [PATCH v2] Make bindresvport() function to multithread-safe

[Mike Frysinger <vapier at gentoo dot org>]

On Wednesday 19 September 2012 02:56:08 Carlos O'Donell wrote:
> On Tue, Sep 18, 2012 at 9:45 PM, Peng Haitao <penght@cn.fujitsu.com> wrote:
> > bindresvport() uses two static variables port and startport which are not
> > protected. It is not safe when in multithread circumstance.
> > 
> > bindresvport() select a port number from the range 512 to 1023, when in
> > multithread circumstance, the port may be 1024. So the static variables
> > will be protected.
> 
> This patch is unacceptable for two reasons:
> 
> (a) We define bindresvport() as non-thread-safe. Therefore the change
> is not required.
> 
> and
> 
> (b) Adding locking to bindresvport() will only slow down the fast path
> in the function.
> 
> You have provided no rationale for the change.
> 
> Until you provide some rationale, or prove that performance doesn't
> matter in the case of this function, the change is unacceptable.
> 
> Does that make sense?

rather than adding locks, what if the static's had __thread added, and getpid 
was changed to gettid.
-mike

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