From cbfdd442c43eab8c62bf2ea5127511cd39e9046d Mon Sep 17 00:00:00 2001 From: Moni Shoua Date: Tue, 11 Dec 2018 13:37:51 +0200 Subject: IB/uverbs: Add helper to get array size from ptr attribute When the parser of an ioctl command has the knowledge that a ptr attribute in a bundle represents an array of structures, it is useful for it to know the number of elements in the array. This is done by dividing the attribute length with the element size. Signed-off-by: Moni Shoua Reviewed-by: Guy Levi Signed-off-by: Leon Romanovsky Signed-off-by: Jason Gunthorpe --- include/rdma/uverbs_ioctl.h | 22 ++++++++++++++++++++++ 1 file changed, 22 insertions(+) (limited to 'include/rdma/uverbs_ioctl.h') diff --git a/include/rdma/uverbs_ioctl.h b/include/rdma/uverbs_ioctl.h index 839a857aa329..bf07cd6336d3 100644 --- a/include/rdma/uverbs_ioctl.h +++ b/include/rdma/uverbs_ioctl.h @@ -719,6 +719,28 @@ uverbs_attr_get_len(const struct uverbs_attr_bundle *attrs_bundle, u16 idx) return attr->ptr_attr.len; } +/* + * uverbs_attr_ptr_get_array_size() - Get array size pointer by a ptr + * attribute. + * @attrs: The attribute bundle + * @idx: The ID of the attribute + * @elem_size: The size of the element in the array + */ +static inline int +uverbs_attr_ptr_get_array_size(struct uverbs_attr_bundle *attrs, u16 idx, + size_t elem_size) +{ + int size = uverbs_attr_get_len(attrs, idx); + + if (size < 0) + return size; + + if (size % elem_size) + return -EINVAL; + + return size / elem_size; +} + /** * uverbs_attr_get_uobjs_arr() - Provides array's properties for attribute for * UVERBS_ATTR_TYPE_IDRS_ARRAY. -- cgit v1.2.3