Re: [PATCH rdma-next v3 08/17] RDMA/efa: Use ib_umem_get_cq_buf() for user CQ buffer

[Jason Gunthorpe <jgg@ziepe.ca>]

On Mon, May 04, 2026 at 03:57:22PM +0200, Jiri Pirko wrote:

> @@ -1172,26 +1174,29 @@ int efa_create_user_cq(struct ib_cq *ibcq, const struct ib_cq_init_attr *attr,
>  	cq->ucontext = ucontext;
>  	cq->size = PAGE_ALIGN(cmd.cq_entry_size * entries * cmd.num_sub_cqs);
>  
> -	if (ibcq->umem) {
> -		if (ibcq->umem->length < cq->size) {
> -			ibdev_dbg(&dev->ibdev, "External memory too small\n");
> -			err = -EINVAL;
> -			goto err_out;
> -		}
> +	umem = ib_umem_get_cq_buf(ibcq->device, udata, cq->size,
> +				  IB_ACCESS_LOCAL_WRITE);
> +	if (IS_ERR(umem)) {
> +		err = PTR_ERR(umem);
> +		goto err_out;
> +	}
> +
> +	cq->umem = umem;
>  
> -		if (!ib_umem_is_contiguous(ibcq->umem)) {
> +	if (umem) {
> +		if (!ib_umem_is_contiguous(umem)) {

This is a little funny, I think umem should not be NULL?

I'd rather the ib_umem_get() not be called if the op is in kernel mode
(this is user_cq so it is never in kernel mode so it should never be
null)

Meaning return a valid umem or return ERR_PTR, never null?

The case that is now NULL should be EINVAL (bad system call arguments)

Jason