On Wed, Dec 30, 2015 at 02:44:21PM +0100, Arnd Bergmann wrote: > On Wednesday 30 December 2015 15:24:47 Michael S. Tsirkin wrote: > > asm-generic variant of smp_store_mb() calls mb() which is stronger > > than implied by both the name and the documentation. > > > > smp_store_mb is only used by core kernel code at the moment, so > > we know no one mis-uses it for an MMIO barrier. > > Make it call smp_mb consistently before some arch-specific > > code uses it as such by mistake. > > > > Signed-off-by: Michael S. Tsirkin <mst@xxxxxxxxxx> > > --- > > include/asm-generic/barrier.h | 2 +- > > 1 file changed, 1 insertion(+), 1 deletion(-) > > > > diff --git a/include/asm-generic/barrier.h b/include/asm-generic/barrier.h > > index 538f8d1..987b2e0 100644 > > --- a/include/asm-generic/barrier.h > > +++ b/include/asm-generic/barrier.h > > @@ -93,7 +93,7 @@ > > #endif /* CONFIG_SMP */ > > > > #ifndef smp_store_mb > > -#define smp_store_mb(var, value) do { WRITE_ONCE(var, value); mb(); } while (0) > > +#define smp_store_mb(var, value) do { WRITE_ONCE(var, value); smp_mb(); } while (0) > > #endif > > > > #ifndef smp_mb__before_atomic > > > > The same patch is already in the tip tree scheduled for 4.5 as d5a73cadf3fd > ("lcoking/barriers, arch: Use smp barriers in smp_store_release()"). Sorry which tree do you mean exactly? > I think you can drop your version. > > arnd Will drop mine, thanks. I kind of dislike that if I just drop it, some arches will temporarily regress to a slower implementation. I think I can just cherry-pick d5a73cadf3fd into my tree: git normally figures such duplicates out nicely. Does this sound good? -- MST _______________________________________________ Virtualization mailing list Virtualization@xxxxxxxxxxxxxxxxxxxxxxxxxx https://lists.linuxfoundation.org/mailman/listinfo/virtualization