linux/drivers/infiniband/hw
Roland Dreier baaad380c0 IB/mthca: Avoid changing userspace ABI to handle DMA write barrier attribute
Commit cb9fbc5c ("IB: expand ib_umem_get() prototype") changed the
mthca userspace ABI to provide a way for userspace to indicate which
memory regions need the DMA write barrier attribute.  However, it is
possible to handle this without breaking existing userspace, by having
the mthca kernel driver recognize whether it is talking to old or new
userspace, depending on the size of the register MR structure passed in.

The only potential drawback of this is that is allows old userspace
(which has a bug with DMA ordering on large SGI Altix systems) to
continue to run on new kernels, but the advantage of allowing old
userspace to continue to work on unaffected systems seems to outweigh
this, and we can print a warning to push people to upgrade their
userspace.

Signed-off-by: Roland Dreier <rolandd@cisco.com>
2008-04-29 13:46:53 -07:00
..
amso1100 IB: expand ib_umem_get() prototype 2008-04-29 08:06:12 -07:00
cxgb3 RDMA/cxgb3: Support peer-2-peer connection setup 2008-04-29 13:46:52 -07:00
ehca IB/ehca: Allocate event queue size depending on max number of CQs and QPs 2008-04-29 13:46:53 -07:00
ipath IB: expand ib_umem_get() prototype 2008-04-29 08:06:12 -07:00
mlx4 mlx4_core: Add a way to set the "collapsed" CQ flag 2008-04-29 13:46:50 -07:00
mthca IB/mthca: Avoid changing userspace ABI to handle DMA write barrier attribute 2008-04-29 13:46:53 -07:00
nes IB: expand ib_umem_get() prototype 2008-04-29 08:06:12 -07:00