Re: [PATCH V2 1/6] namespaces: assign each namespace instance a serial number

On 14/05/10, Eric Paris wrote: > On Fri, 2014-05-09 at 20:27 -0400, Richard Guy Briggs wrote: > > Generate and assign a serial number per namespace instance since boot. > > > > Use a serial number per namespace (unique across one boot of one kernel) > > instead of the inode number (which is claimed to have had the right to change > > reserved and is not necessarily unique if there is more than one proc fs) to > > uniquely identify it per kernel boot. > > > > Signed-off-by: Richard Guy Briggs <rgb(a)redhat.com&gt; > > --- > > > +/** > > + * ns_serial - compute a serial number for the namespace > > + * > > + * Compute a serial number for the namespace to uniquely identify it in > > + * audit records. > > + */ > > +unsigned long long ns_serial(void) > > +{ > > + static DEFINE_SPINLOCK(serial_lock); > > + static unsigned long long serial = 4; /* reserved for IPC, UTS, user, PID */ > > + unsigned long flags; > > + > > + spin_lock_irqsave(&serial_lock, flags); > > + ++serial; > > + spin_unlock_irqrestore(&serial_lock, flags); > > + BUG_ON(!serial); > > + > > + return serial; > > +} > > + > > static inline struct nsproxy *create_nsproxy(void) > > { > > struct nsproxy *nsproxy; > > atomic64_t instead of doing it yourself? I'm willing to switch to atomic64_*. Thanks for pointing out its existence.

> and why _irqsave() ? Can we seriously create new namespaces in irq > context? If you use the atomic though, you don't have to worry about > it... Agreed. That is unlikely. - RGB -- Richard Guy Briggs <rbriggs(a)redhat.com&gt; Senior Software Engineer, Kernel Security, AMER ENG Base Operating Systems, Red Hat Remote, Ottawa, Canada Voice: +1.647.777.2635, Internal: (81) 32635, Alt: +1.613.693.0684x3545