On 09/04/2015 05:32 PM, Jason Gunthorpe wrote:
> On Fri, Sep 04, 2015 at 05:17:38PM -0400, Doug Ledford wrote:
>> + /*
>> + * In order to maintain backward/forward binary compatibility
>> + * with libmlx4-1.0.6, which has the original version of the
>> + * flow steering patches, we need to set the two
>> + * ABI_compat_placeholder entries to match the driver
>> + * set flow entries. This is because, in the specific instance
>> + * of using libmlx4-1.0.6 with the fixed version of
>> + * libibvberbs, the ibv_create_flow inline function already
>> + * compiled into libmlx4-1.0.6 will be loooking in the
>> + * ABI_placeholder spots for the function pointer to the
>> + * create and destroy flow verbs.
>> */
>
> This isn't quite the right comment, it has very little to do with mlx,
> ibv_create_flow is the user entry point, the above applies to
> everything linked to ibverbs.
You're right. I'll correct that.
> My suggestion was to not change the ibverbs->user ABI at all and just
> mangle the driver side, ie move the ABI_placeholder to what was drv_
> instead of lib_.
As you pointed out, this doesn't make the entire matrix of old/new
driver/libibverbs/app work. I can think of two things that would be
ugly about doing it this way if we wanted to make that matrix fully
operational. With the way I did it, things are clean in the new driver
and mostly clean in the new libibverbs, and the full matrix works.
> Can't see anything wrong with it this way, off hand, other than the
> comment.
Thanks for looking at it ;-)
--
Doug Ledford <dledford@xxxxxxxxxx>
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