Messages in this thread | | | Date | Wed, 11 Nov 2015 17:44:01 +0000 | From | Will Deacon <> | Subject | Re: [PATCH 2/2] arm64: bpf: add BPF XADD instruction |
| |
On Wed, Nov 11, 2015 at 12:35:48PM -0500, David Miller wrote: > From: Alexei Starovoitov <alexei.starovoitov@gmail.com> > Date: Wed, 11 Nov 2015 09:27:00 -0800 > > > BPF_XADD == atomic_add() in kernel. period. > > we are not going to deprecate it or introduce something else. > > Agreed, it makes no sense to try and tie C99 or whatever atomic > semantics to something that is already clearly defined to have > exactly kernel atomic_add() semantics.
... and which is emitted by LLVM when asked to compile __sync_fetch_and_add, which has clearly defined (yet conflicting) semantics.
If the discrepancy is in LLVM (and it sounds like it is), then I'll raise a bug over there instead.
Will
| |