[ofa-general] Re: [PATCHv4 RFC] Scalable Reliable Connection: API and documentation
jackm at dev.mellanox.co.il
Sun Aug 12 23:34:07 PDT 2007
On Sunday 12 August 2007 19:49, Michael S. Tsirkin wrote:
> > Why not add xrc_domain to the driver-data area? Because the xrc_domain is a ib verbs-layer construct.
> It doesn't follow, necessarily.
> Will we be able to void breaking kernel-user ABI if we stick domain
> handle in driver-specific area?
Are you suggesting the following:
1. Do NOT increment the kernel-user ABI
2. Put all src-related changes into the driver-specific area
3. Rely the fact that if userspace is using driver libraries which do not support SRC,
the src-related functions will not be present, and libibverbs will reject the src-related
NOTE: This may be the case for SRC function calls. However, there is no check on qp-type in userspace
during ibv_create_qp. Its possible for the user to indicate IBV_QPT_SRC, have it go all the
way to kernel-space -- and kernel space will take the (garbage) value for the src-domain number.
I think we will find other such holes if we don't increment the kernel-user ABI version.
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