From 1697599ee301a52cded6499a09bd609f7f63fd06 Mon Sep 17 00:00:00 2001 From: Jakub Kicinski Date: Thu, 9 Feb 2017 09:17:27 -0800 Subject: bitfield.h: add FIELD_FIT() helper Add a helper for checking at runtime that a value will fit inside a specified field/mask. Signed-off-by: Jakub Kicinski Signed-off-by: David S. Miller --- include/linux/bitfield.h | 13 +++++++++++++ 1 file changed, 13 insertions(+) (limited to 'include/linux') diff --git a/include/linux/bitfield.h b/include/linux/bitfield.h index f6505d83069d..8b9d6fff002d 100644 --- a/include/linux/bitfield.h +++ b/include/linux/bitfield.h @@ -62,6 +62,19 @@ (1ULL << __bf_shf(_mask))); \ }) +/** + * FIELD_FIT() - check if value fits in the field + * @_mask: shifted mask defining the field's length and position + * @_val: value to test against the field + * + * Return: true if @_val can fit inside @_mask, false if @_val is too big. + */ +#define FIELD_FIT(_mask, _val) \ + ({ \ + __BF_FIELD_CHECK(_mask, 0ULL, _val, "FIELD_FIT: "); \ + !((((typeof(_mask))_val) << __bf_shf(_mask)) & ~(_mask)); \ + }) + /** * FIELD_PREP() - prepare a bitfield element * @_mask: shifted mask defining the field's length and position -- cgit v1.2.3-58-ga151