bpf: Support bitfield read access in btf_struct_access

		return -EINVAL;

	}

	for_each_member(i, t, member) {

		if (btf_member_bitfield_size(t, member))

			/* bitfields are not supported yet */

			continue;

	if (off + size > t->size) {

		bpf_log(log, "access beyond struct %s at off %u size %u\n",

			tname, off, size);

		return -EACCES;

	}

	for_each_member(i, t, member) {

		/* offset of the field in bytes */

		moff = btf_member_bit_offset(t, member) / 8;

		if (off + size <= moff)

			/* won't find anything, field is already too far */

			break;

		if (btf_member_bitfield_size(t, member)) {

			u32 end_bit = btf_member_bit_offset(t, member) +

				btf_member_bitfield_size(t, member);

			/* off <= moff instead of off == moff because clang

			 * does not generate a BTF member for anonymous

			 * bitfield like the ":16" here:

			 * struct {

			 *	int :16;

			 *	int x:8;

			 * };

			 */

			if (off <= moff &&

			    BITS_ROUNDUP_BYTES(end_bit) <= off + size)

				return SCALAR_VALUE;

			/* off may be accessing a following member

			 *

			 * or

			 *

			 * Doing partial access at either end of this

			 * bitfield.  Continue on this case also to

			 * treat it as not accessing this bitfield

			 * and eventually error out as field not

			 * found to keep it simple.

			 * It could be relaxed if there was a legit

			 * partial access case later.

			 */

			continue;

		}

		/* In case of "off" is pointing to holes of a struct */

		if (off < moff)

			continue;

			break;

		/* type of the field */

		mtype = btf_type_by_id(btf_vmlinux, member->type);