Re: [PATCH rdma-next 3/4] IB/mlx5: Extend QP creation to get uar page index from user space

[Jason Gunthorpe <jgg@mellanox.com>]

On Wed, Mar 18, 2020 at 02:43:28PM +0200, Leon Romanovsky wrote:
> From: Yishai Hadas <yishaih@mellanox.com>
> 
> Extend QP creation to get uar page index from user space, this mode can
> be used with the UAR dynamic mode APIs to allocate/destroy a UAR object.
> 
> As part of enabling this option blocked the weird/un-supported cross
> channel option which uses index 0 hard-coded.
> 
> This QP flag wasn't exposed to user space as part of any formal upstream
> release, the dynamic option can allow having valid UAR page index
> instead.
> 
> Signed-off-by: Yishai Hadas <yishaih@mellanox.com>
> Reviewed-by: Michael Guralnik <michaelgur@mellanox.com>
> Signed-off-by: Leon Romanovsky <leonro@mellanox.com>
>  drivers/infiniband/hw/mlx5/qp.c | 27 +++++++++++++++++----------
>  include/uapi/rdma/mlx5-abi.h    |  1 +
>  2 files changed, 18 insertions(+), 10 deletions(-)
> 
> diff --git a/drivers/infiniband/hw/mlx5/qp.c b/drivers/infiniband/hw/mlx5/qp.c
> index 88db580f7272..380ba3321851 100644
> +++ b/drivers/infiniband/hw/mlx5/qp.c
> @@ -919,6 +919,7 @@ static int create_user_qp(struct mlx5_ib_dev *dev, struct ib_pd *pd,
>  	void *qpc;
>  	int err;
>  	u16 uid;
> +	u32 uar_flags;
>  
>  	err = ib_copy_from_udata(&ucmd, udata, sizeof(ucmd));
>  	if (err) {
> @@ -928,24 +929,29 @@ static int create_user_qp(struct mlx5_ib_dev *dev, struct ib_pd *pd,
>  
>  	context = rdma_udata_to_drv_context(udata, struct mlx5_ib_ucontext,
>  					    ibucontext);
> -	if (ucmd.flags & MLX5_QP_FLAG_BFREG_INDEX) {
> +	uar_flags = ucmd.flags & (MLX5_QP_FLAG_UAR_PAGE_INDEX |
> +				  MLX5_QP_FLAG_BFREG_INDEX);
> +	switch (uar_flags) {

Do we really need this temporary uar_flags?

Jason