Re: [PATCH rdma-next v6 3/4] RDMA/bnxt_re: Direct Verbs: Support DBR verbs

[Jason Gunthorpe <jgg@ziepe.ca>]

On Wed, Dec 24, 2025 at 09:56:01AM +0530, Sriharsha Basavapatna wrote:
> +static int UVERBS_HANDLER(BNXT_RE_METHOD_DBR_ALLOC)(struct uverbs_attr_bundle *attrs)
> +{
> +	struct bnxt_re_dv_db_region dbr = {};
> +	struct bnxt_re_alloc_dbr_obj *obj;
> +	struct bnxt_re_ucontext *uctx;
> +	struct ib_ucontext *ib_uctx;
> +	struct bnxt_qplib_dpi *dpi;
> +	struct bnxt_re_dev *rdev;
> +	struct ib_uobject *uobj;
> +	u64 mmap_offset;
> +	int ret;
> +
> +	ib_uctx = ib_uverbs_get_ucontext(attrs);
> +	if (IS_ERR(ib_uctx))
> +		return PTR_ERR(ib_uctx);
> +
> +	uctx = container_of(ib_uctx, struct bnxt_re_ucontext, ib_uctx);
> +	rdev = uctx->rdev;
> +	uobj = uverbs_attr_get_uobject(attrs, BNXT_RE_DV_ALLOC_DBR_HANDLE);
> +
> +	obj = kzalloc(sizeof(*obj), GFP_KERNEL);
> +	if (!obj)
> +		return -ENOMEM;
> +
> +	dpi = &obj->dpi;
> +	ret = bnxt_qplib_alloc_uc_dpi(&rdev->qplib_res, dpi);
> +	if (ret)
> +		goto free_mem;
> +
> +	obj->entry = bnxt_re_mmap_entry_insert(uctx, 0, BNXT_RE_MMAP_UC_DB,
> +					       &mmap_offset);
> +	if (!obj->entry) {
> +		ret = -ENOMEM;
> +		goto free_dpi;
> +	}
> +
> +	obj->rdev = rdev;
> +	dbr.umdbr = dpi->umdbr;
> +	dbr.dpi = dpi->dpi;
> +
> +	ret = uverbs_copy_to_struct_or_zero(attrs, BNXT_RE_DV_ALLOC_DBR_ATTR,
> +					    &dbr, sizeof(dbr));
> +	if (ret)
> +		goto free_entry;
> +
> +	ret = uverbs_copy_to(attrs, BNXT_RE_DV_ALLOC_DBR_OFFSET,
> +			     &mmap_offset, sizeof(mmap_offset));
> +	if (ret)
> +		goto free_entry;
> +
> +	uobj->object = obj;
> +	uverbs_finalize_uobj_create(attrs, BNXT_RE_DV_ALLOC_DBR_HANDLE);
> +	hash_add(rdev->dpi_hash, &obj->hash_entry, dpi->dpi);

This is out of order, hash_del is done inside bnxt_re_dv_dbr_cleanup()
so it should be before finalize, but it isn't a bug.

It should probably be written like this:

	uobj->object = obj;
	hash_add(rdev->dpi_hash, &obj->hash_entry, dpi->dpi);
	uverbs_finalize_uobj_create(attrs, BNXT_RE_DV_ALLOC_DBR_HANDLE);

	ret = uverbs_copy_to_struct_or_zero(attrs, BNXT_RE_DV_ALLOC_DBR_ATTR,
					    &dbr, sizeof(dbr));
	if (ret)
		return ret;

	ret = uverbs_copy_to(attrs, BNXT_RE_DV_ALLOC_DBR_OFFSET,
			     &mmap_offset, sizeof(mmap_offset));
	if (ret)
		return ret;
	return 0;

Jason