Re: [PATCH rdma-next 28/50] RDMA/siw: Split user and kernel CQ creation paths

[Bernard Metzler <bernard.metzler@linux.dev>]

On 13.02.2026 11:58, Leon Romanovsky wrote:
> From: Leon Romanovsky <leonro@nvidia.com>
> 
> Separate the CQ creation logic into distinct kernel and user flows.
> 
> Signed-off-by: Leon Romanovsky <leonro@nvidia.com>
> ---
>   drivers/infiniband/sw/siw/siw_main.c  |   1 +
>   drivers/infiniband/sw/siw/siw_verbs.c | 111 +++++++++++++++++++++++-----------
>   drivers/infiniband/sw/siw/siw_verbs.h |   2 +
>   3 files changed, 80 insertions(+), 34 deletions(-)
> 
> diff --git a/drivers/infiniband/sw/siw/siw_main.c b/drivers/infiniband/sw/siw/siw_main.c
> index 5168307229a9..75dcf3578eac 100644
> --- a/drivers/infiniband/sw/siw/siw_main.c
> +++ b/drivers/infiniband/sw/siw/siw_main.c
> @@ -232,6 +232,7 @@ static const struct ib_device_ops siw_device_ops = {
>   	.alloc_pd = siw_alloc_pd,
>   	.alloc_ucontext = siw_alloc_ucontext,
>   	.create_cq = siw_create_cq,
> +	.create_user_cq = siw_create_user_cq,
>   	.create_qp = siw_create_qp,
>   	.create_srq = siw_create_srq,
>   	.dealloc_driver = siw_device_cleanup,
> diff --git a/drivers/infiniband/sw/siw/siw_verbs.c b/drivers/infiniband/sw/siw/siw_verbs.c
> index efa2f097b582..92b25b389b69 100644
> --- a/drivers/infiniband/sw/siw/siw_verbs.c
> +++ b/drivers/infiniband/sw/siw/siw_verbs.c
> @@ -1139,15 +1139,15 @@ int siw_destroy_cq(struct ib_cq *base_cq, struct ib_udata *udata)
>    * @attrs: uverbs bundle
>    */
>   
> -int siw_create_cq(struct ib_cq *base_cq, const struct ib_cq_init_attr *attr,
> -		  struct uverbs_attr_bundle *attrs)
> +int siw_create_user_cq(struct ib_cq *base_cq, const struct ib_cq_init_attr *attr,
> +		       struct uverbs_attr_bundle *attrs)
>   {
>   	struct ib_udata *udata = &attrs->driver_udata;
>   	struct siw_device *sdev = to_siw_dev(base_cq->device);
>   	struct siw_cq *cq = to_siw_cq(base_cq);
>   	int rv, size = attr->cqe;
>   
> -	if (attr->flags)
> +	if (attr->flags || base_cq->umem)
>   		return -EOPNOTSUPP;
>   
>   	if (atomic_inc_return(&sdev->num_cq) > SIW_MAX_CQ) {
> @@ -1155,7 +1155,7 @@ int siw_create_cq(struct ib_cq *base_cq, const struct ib_cq_init_attr *attr,
>   		rv = -ENOMEM;
>   		goto err_out;
>   	}
> -	if (size < 1 || size > sdev->attrs.max_cqe) {
> +	if (attr->cqe > sdev->attrs.max_cqe) {
>   		siw_dbg(base_cq->device, "CQ size error: %d\n", size);
>   		rv = -EINVAL;
>   		goto err_out;
> @@ -1164,13 +1164,8 @@ int siw_create_cq(struct ib_cq *base_cq, const struct ib_cq_init_attr *attr,
>   	cq->base_cq.cqe = size;
>   	cq->num_cqe = size;
>   
> -	if (udata)
> -		cq->queue = vmalloc_user(size * sizeof(struct siw_cqe) +
> -					 sizeof(struct siw_cq_ctrl));
> -	else
> -		cq->queue = vzalloc(size * sizeof(struct siw_cqe) +
> -				    sizeof(struct siw_cq_ctrl));
> -
> +	cq->queue = vmalloc_user(size * sizeof(struct siw_cqe) +
> +				 sizeof(struct siw_cq_ctrl));
>   	if (cq->queue == NULL) {
>   		rv = -ENOMEM;
>   		goto err_out;
> @@ -1182,33 +1177,32 @@ int siw_create_cq(struct ib_cq *base_cq, const struct ib_cq_init_attr *attr,
>   
>   	cq->notify = (struct siw_cq_ctrl *)&cq->queue[size];
>   
> -	if (udata) {
> -		struct siw_uresp_create_cq uresp = {};
> -		struct siw_ucontext *ctx =
> -			rdma_udata_to_drv_context(udata, struct siw_ucontext,
> -						  base_ucontext);
> -		size_t length = size * sizeof(struct siw_cqe) +
> -			sizeof(struct siw_cq_ctrl);
> +	struct siw_uresp_create_cq uresp = {};
> +	struct siw_ucontext *ctx =
> +		rdma_udata_to_drv_context(udata, struct siw_ucontext,
> +					  base_ucontext);
> +	size_t length = size * sizeof(struct siw_cqe) +
> +		sizeof(struct siw_cq_ctrl);
>   
> -		cq->cq_entry =
> -			siw_mmap_entry_insert(ctx, cq->queue,
> -					      length, &uresp.cq_key);
> -		if (!cq->cq_entry) {
> -			rv = -ENOMEM;
> -			goto err_out;
> -		}
> +	cq->cq_entry =
> +		siw_mmap_entry_insert(ctx, cq->queue,
> +				      length, &uresp.cq_key);
> +	if (!cq->cq_entry) {
> +		rv = -ENOMEM;
> +		goto err_out;
> +	}
>   
> -		uresp.cq_id = cq->id;
> -		uresp.num_cqe = size;
> +	uresp.cq_id = cq->id;
> +	uresp.num_cqe = size;
>   
> -		if (udata->outlen < sizeof(uresp)) {
> -			rv = -EINVAL;
> -			goto err_out;
> -		}
> -		rv = ib_copy_to_udata(udata, &uresp, sizeof(uresp));
> -		if (rv)
> -			goto err_out;
> +	if (udata->outlen < sizeof(uresp)) {
> +		rv = -EINVAL;
> +		goto err_out;
>   	}
> +	rv = ib_copy_to_udata(udata, &uresp, sizeof(uresp));
> +	if (rv)
> +		goto err_out;
> +
>   	return 0;
>   
>   err_out:
> @@ -1227,6 +1221,55 @@ int siw_create_cq(struct ib_cq *base_cq, const struct ib_cq_init_attr *attr,
>   	return rv;
>   }
>   
> +int siw_create_cq(struct ib_cq *base_cq, const struct ib_cq_init_attr *attr,
> +		  struct uverbs_attr_bundle *attrs)
> +{
> +	struct siw_device *sdev = to_siw_dev(base_cq->device);
> +	struct siw_cq *cq = to_siw_cq(base_cq);
> +	int rv, size = attr->cqe;
> +
> +	if (attr->flags)
> +		return -EOPNOTSUPP;
> +
> +	if (atomic_inc_return(&sdev->num_cq) > SIW_MAX_CQ) {
> +		siw_dbg(base_cq->device, "too many CQ's\n");
> +		rv = -ENOMEM;
> +		goto err_out;
> +	}
> +	if (size < 1 || size > sdev->attrs.max_cqe) {

isn't there now also a check for zero sized CQ in
__ib_alloc_cq(), which obsoletes that < 1 check?

Everything looks right otherwise.

Thanks,
Bernard.

> +		siw_dbg(base_cq->device, "CQ size error: %d\n", size);
> +		rv = -EINVAL;
> +		goto err_out;
> +	}
> +	size = roundup_pow_of_two(size);
> +	cq->base_cq.cqe = size;
> +	cq->num_cqe = size;
> +
> +	cq->queue = vzalloc(size * sizeof(struct siw_cqe) +
> +			    sizeof(struct siw_cq_ctrl));
> +	if (cq->queue == NULL) {
> +		rv = -ENOMEM;
> +		goto err_out;
> +	}
> +	get_random_bytes(&cq->id, 4);
> +	siw_dbg(base_cq->device, "new CQ [%u]\n", cq->id);
> +
> +	spin_lock_init(&cq->lock);
> +
> +	cq->notify = (struct siw_cq_ctrl *)&cq->queue[size];
> +
> +	return 0;
> +
> +err_out:
> +	siw_dbg(base_cq->device, "CQ creation failed: %d", rv);
> +
> +	if (cq->queue)
> +		vfree(cq->queue);
> +	atomic_dec(&sdev->num_cq);
> +
> +	return rv;
> +}
> +
>   /*
>    * siw_poll_cq()
>    *
> diff --git a/drivers/infiniband/sw/siw/siw_verbs.h b/drivers/infiniband/sw/siw/siw_verbs.h
> index e9f4463aecdc..527c356b55af 100644
> --- a/drivers/infiniband/sw/siw/siw_verbs.h
> +++ b/drivers/infiniband/sw/siw/siw_verbs.h
> @@ -44,6 +44,8 @@ int siw_query_device(struct ib_device *base_dev, struct ib_device_attr *attr,
>   		     struct ib_udata *udata);
>   int siw_create_cq(struct ib_cq *base_cq, const struct ib_cq_init_attr *attr,
>   		  struct uverbs_attr_bundle *attrs);
> +int siw_create_user_cq(struct ib_cq *base_cq, const struct ib_cq_init_attr *attr,
> +		       struct uverbs_attr_bundle *attrs);
>   int siw_query_port(struct ib_device *base_dev, u32 port,
>   		   struct ib_port_attr *attr);
>   int siw_query_gid(struct ib_device *base_dev, u32 port, int idx,
>