Re: [PATCH rdma-next v1 1/6] IB/uverbs: Allow CQ moderation with modify CQ
From: Yishai Hadas <hidden>
Date: 2017-10-31 11:31:28
On 10/31/2017 7:08 AM, Leon Romanovsky wrote:
On Mon, Oct 30, 2017 at 05:07:53PM -0600, Jason Gunthorpe wrote:quoted
On Mon, Oct 30, 2017 at 09:09:52PM +0200, Leon Romanovsky wrote:quoted
However, I don't think that kernel to libibverbs API should follow the same path. The centralized entry points to the kernel provides better enforcement and minimizes system call bloat.How so? I didn't think selinux intersected with the CQs at all.. I've never worried about the # of verbs entries, we have so many already.Not SELinux enforcement, but various copy_{to|from}_user checks, unified return values, easy folding in case of errors, e.t.c. It is a matter of personal view and less technical thing. You prefer bazillion entry points to the kernel and I think that such design good for user-space only, and mostly not applicable for kernel<->user interfaces.
Even for the user area having a dedicated 'setter' per field might bring some redundant overhead and limitation. This will prevent the option from application to modify few fields in one API and resulted in a system call per field. Also libibverbs and user drivers may need to maintain some wrapping over the kernel command which in turn might lead to some extra/duplication of code. I would vote to follow modify QP/SRQ/WQ by having one API with an 'attr_mask' field as this series has introduced in both kernel and user. The matching user space series was published and can be seen at: https://github.com/linux-rdma/rdma-core/pull/238 -- To unsubscribe from this list: send the line "unsubscribe linux-rdma" in the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org More majordomo info at http://vger.kernel.org/majordomo-info.html