Re: [PATCH rdma-next] RDMA/mlx5: Make sure that UMR page is aligned to PAGE_SIZE

[Jason Gunthorpe]

On Thu, Jul 23, 2026 at 11:35:55AM +0300, Leon Romanovsky wrote:
> On Wed, Jul 22, 2026 at 04:41:03PM -0300, Jason Gunthorpe wrote:
> > On Wed, Jul 22, 2026 at 02:41:13PM +0300, Leon Romanovsky wrote:
> > > From: Leon Romanovsky <leonro@xxxxxxxxxx>
> > > 
> > > The UMR XLT buffer needs to be aligned to PAGE_SIZE.
> > 
> > Why? It goes into a sgl? The device certainly does not work on
> > PAGE_SIZE, so if there is some alignment here it should be the MLX5
> > adaptor alignment
> 
> We need an alignment to 2Kb as a minimum here.
> 
> In our case, we got the following assert:
>  ‘mlx5_post_send_umr: assertion failed (MLX5_GET64(umr_pointer_desc_argument, data, address) & 0×7ff == 0)’

So use that value, or the adaptor page size

There is no reason to align this to 64k if we need a 2k only.

Jason