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

[Leon Romanovsky <leon@kernel.org>]

On Wed, Mar 18, 2020 at 10:05:14AM -0300, Jason Gunthorpe wrote:
> 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?

I thinks that it is more clear, this is why I used temp variable.

Thanks

>
> Jason