Re: [PATCH rdma-core 00/14] Revise the DMA barrier macros in ibverbs

[Doug Ledford <dledford-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>]

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On Thu, 2017-02-16 at 12:22 -0700, Jason Gunthorpe wrote:
> Now that the header is private to the library we can change it.
> 
> We have never had a clear definition for what our wmb() or wc_wmb()
> even do,
> and they don't match the same macros in the kernel. This causes
> problems for
> non x86 arches as they have no idea what to put in their versions of
> the macros
> and often just put the strongest thing.
> 
> This also causes problems for the driver authors who have no idea how
> to use
> these barriers properly, there are several instances of that :(
> 
> My approach here is to introduce a selection of macros that have
> narrow and
> clearly defined purposes. The selection is based on things the set of
> drivers
> actually do, which turns out to be fairly narrowly defined.
> 
> Then I went through all the drivers and adjusted them to various
> degrees to
> use the new macro names. In a few drivers I added more/stronger
> barriers.
> Overall this tries hard not to break anything by weaking existing
> barriers.
> 
> A future project for someone would be to see if the CPU ASM makes
> sense..
> 
> https://github.com/linux-rdma/rdma-core/pull/79
> 
> Jason Gunthorpe (14):
>   mlx5: Use stdatomic for the in_use barrier
>   Provide new names for the CPU barriers related to DMA
>   cxgb3: Update to use new udma write barriers
>   cxgb4: Update to use new udma write barriers
>   hns: Update to use new udma write barriers
>   i40iw: Get rid of unique barrier macros
>   mlx4: Update to use new udma write barriers
>   mlx5: Update to use new udma write barriers
>   nes: Update to use new udma write barriers
>   mthca: Update to use new mmio write barriers
>   ocrdma: Update to use new udma write barriers
>   qedr: Update to use new udma write barriers
>   vmw_pvrdma: Update to use new udma write barriers
>   Remove the old barrier macros
> 
>  providers/cxgb3/cq.c             |   2 +
>  providers/cxgb3/cxio_wr.h        |   2 +-
>  providers/cxgb4/qp.c             |  20 +++-
>  providers/cxgb4/t4.h             |  48 ++++++--
>  providers/cxgb4/verbs.c          |   2 +
>  providers/hns/hns_roce_u_hw_v1.c |  13 +-
>  providers/i40iw/i40iw_osdep.h    |  14 ---
>  providers/i40iw/i40iw_uk.c       |  26 ++--
>  providers/mlx4/cq.c              |   6 +-
>  providers/mlx4/qp.c              |  19 +--
>  providers/mlx4/srq.c             |   2 +-
>  providers/mlx5/cq.c              |   8 +-
>  providers/mlx5/mlx5.h            |   7 +-
>  providers/mlx5/qp.c              |  18 +--
>  providers/mlx5/srq.c             |   2 +-
>  providers/mthca/cq.c             |  10 +-
>  providers/mthca/doorbell.h       |   2 +-
>  providers/mthca/qp.c             |  20 ++--
>  providers/mthca/srq.c            |   6 +-
>  providers/nes/nes_uverbs.c       |  16 +--
>  providers/ocrdma/ocrdma_verbs.c  |  16 ++-
>  providers/qedr/qelr_verbs.c      |  32 +++--
>  providers/vmw_pvrdma/cq.c        |   6 +-
>  providers/vmw_pvrdma/qp.c        |   8 +-
>  util/udma_barrier.h              | 250 +++++++++++++++++++++++++++
> ------------
>  25 files changed, 354 insertions(+), 201 deletions(-)

Thanks, series merged.

-- 
Doug Ledford <dledford@redhat.com>
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