[PATCH 1/2] namespaces: give each namespace a serial number
Serge E. Hallyn
serge at hallyn.com
Thu May 1 22:51:16 UTC 2014
Quoting Richard Guy Briggs (rgb at redhat.com):
Most of this looks reasonable, but I'm curious about something,
> +/**
> + * ns_serial - compute a serial number for the namespace
> + *
> + * Compute a serial number for the namespace to uniquely identify it in
> + * audit records.
> + */
> +unsigned int ns_serial(void)
> +{
> + static DEFINE_SPINLOCK(serial_lock);
> + static unsigned int serial = 4; /* reserved for IPC, UTS, user, PID */
> +
> + unsigned long flags;
> + unsigned int ret;
> +
> + spin_lock_irqsave(&serial_lock, flags);
> + do {
> + ret = ++serial;
> + } while (unlikely(!ret));
Why exactly are you doing this? Surely if serial is going to
wrap around we've got a bigger problem than just wanting go
bump one more time?
> + spin_unlock_irqrestore(&serial_lock, flags);
> +
> + return ret;
> +}
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