On 05/12/16 11:05, Andrew Cooper wrote: > Barriers are a complicated topic, a common source of confusion in submitted > code, and their incorrect use is a common cause of bugs. It *really* doesn't > help when Xen's API is the same as Linux, but its ABI different. > > Bring the two back in line, so programmers stand a chance of actually getting > their use correct. > > As Xen has no current need for mandatory barriers, leave them commented out to > avoid accidential misue. > > No functional change. > > Signed-off-by: Andrew Cooper <andrew.coop...@citrix.com> > --- > CC: Jan Beulich <jbeul...@suse.com> > --- > xen/include/asm-x86/system.h | 31 +++++++++++++++++++++++-------- > xen/include/asm-x86/x86_64/system.h | 3 --- > 2 files changed, 23 insertions(+), 11 deletions(-) > > diff --git a/xen/include/asm-x86/system.h b/xen/include/asm-x86/system.h > index 9cb6fd7..9cd401a 100644 > --- a/xen/include/asm-x86/system.h > +++ b/xen/include/asm-x86/system.h > @@ -164,23 +164,38 @@ static always_inline unsigned long __xadd( > ((typeof(*(ptr)))__xadd(ptr, (typeof(*(ptr)))(v), sizeof(*(ptr)))) > > /* > + * Mandatory barriers, for the ordering of reads and writes with MMIO devices > + * mapped with reduced cacheability. > + * > + * Xen has no such device drivers, and therefore no need for mandatory > + * barriers. These these are hidden to avoid their misuse; If a future need
Duplicate "these". Juergen _______________________________________________ Xen-devel mailing list Xen-devel@lists.xen.org https://lists.xen.org/xen-devel
