Re: [PATCH rdma-next 03/13] RDMA: Split kernel-only create QP flags from uverbs create QP flags

From: Leon Romanovsky <leon@kernel.org>
To: Jason Gunthorpe <jgg@nvidia.com>
Cc: Israel Rukshin <israelr@nvidia.com>,
	Bryan Tan <bryantan@vmware.com>, Christoph Hellwig <hch@lst.de>,
	Eric Dumazet <edumazet@google.com>,
	Jakub Kicinski <kuba@kernel.org>, Jens Axboe <axboe@fb.com>,
	Keith Busch <kbusch@kernel.org>,
	linux-kernel@vger.kernel.org, linux-nvme@lists.infradead.org,
	linux-rdma@vger.kernel.org, linux-trace-kernel@vger.kernel.org,
	Masami Hiramatsu <mhiramat@kernel.org>,
	Max Gurtovoy <mgurtovoy@nvidia.com>,
	netdev@vger.kernel.org, Paolo Abeni <pabeni@redhat.com>,
	Saeed Mahameed <saeedm@nvidia.com>,
	Sagi Grimberg <sagi@grimberg.me>,
	Selvin Xavier <selvin.xavier@broadcom.com>,
	Steven Rostedt <rostedt@goodmis.org>,
	Vishnu Dasa <vdasa@vmware.com>, Yishai Hadas <yishaih@nvidia.com>
Subject: Re: [PATCH rdma-next 03/13] RDMA: Split kernel-only create QP flags from uverbs create QP flags
Date: Tue, 17 Jan 2023 16:14:22 +0200	[thread overview]
Message-ID: <Y8atPjQ1x75tBdib@unreal> (raw)
In-Reply-To: <Y8anaBBZDOGF471q@nvidia.com>

On Tue, Jan 17, 2023 at 09:49:28AM -0400, Jason Gunthorpe wrote:
> On Tue, Jan 17, 2023 at 02:03:07PM +0200, Leon Romanovsky wrote:
> > On Mon, Jan 16, 2023 at 01:39:38PM -0400, Jason Gunthorpe wrote:
> > > On Mon, Jan 16, 2023 at 03:05:50PM +0200, Leon Romanovsky wrote:
> > > 
> > > > diff --git a/drivers/infiniband/hw/mlx4/mlx4_ib.h b/drivers/infiniband/hw/mlx4/mlx4_ib.h
> > > > index 17fee1e73a45..c553bf0eb257 100644
> > > > --- a/drivers/infiniband/hw/mlx4/mlx4_ib.h
> > > > +++ b/drivers/infiniband/hw/mlx4/mlx4_ib.h
> > > > @@ -184,7 +184,7 @@ enum mlx4_ib_qp_flags {
> > > >  	/* Mellanox specific flags start from IB_QP_CREATE_RESERVED_START */
> > > >  	MLX4_IB_ROCE_V2_GSI_QP = MLX4_IB_QP_CREATE_ROCE_V2_GSI,
> > > >  	MLX4_IB_SRIOV_TUNNEL_QP = 1 << 30,
> > > > -	MLX4_IB_SRIOV_SQP = 1 << 31,
> > > > +	MLX4_IB_SRIOV_SQP = 1ULL << 31,
> > > >  };
> > > 
> > > These should be moved to a uapi if we are saying they are userspace
> > > available
> > > 
> > > But I'm not sure they are?
> > 
> > I don't think so.
> 
> Then they should be > 32 bits right?

Right now, they are in reserved range:
        /* reserve bits 26-31 for low level drivers' internal use */
        IB_QP_CREATE_RESERVED_START             = 1 << 26,
        IB_QP_CREATE_RESERVED_END               = 1ULL << 31,

If we move them to kernel part, we will need to define reserved range
there too. So we just "burn" extra bits just for mlx4, also I don't see
any reason to promote mlx4 bits to be general ones.

Thanks

> 
> Jason