On Wed, May 04, 2016 at 02:39:40PM +0200, Petr Mladek wrote: > > + * This barrier also ensures that if another CPU goes through the > > + * syscall barrier, sees the TIF_PATCH_PENDING writes in > > + * klp_start_transition(), and calls klp_patch_task(), it also sees the > > + * above write to the target state. Otherwise it can put the task in > > + * the wrong universe. > > + */ > > By other words, it makes sure that klp_patch_task() will assign the > right patch_state. Where klp_patch_task() could not be called > before we set TIF_PATCH_PENDING in klp_start_transition(). > > > + smp_wmb(); > > +}
So I've not read the patch; but ending a function with an smp_wmb() feels wrong. A wmb orders two stores, and I feel both stores should be well visible in the same function. _______________________________________________ Linuxppc-dev mailing list Linuxppc-dev@lists.ozlabs.org https://lists.ozlabs.org/listinfo/linuxppc-dev
