Commit 88db6d1e authored by Michal Kubecek's avatar Michal Kubecek Committed by David S. Miller
Browse files

ethtool: add ethnl_parse_bitset() helper 



Unlike other SET type commands, modifying netdev features is required to
provide a reply telling userspace what was actually changed, compared to
what was requested. For that purpose, the "modified" flag provided by
ethnl_update_bitset() is not sufficient, we need full information which
bits were requested to change.

Therefore provide ethnl_parse_bitset() returning effective value and mask
bitmaps equivalent to the contents of a bitset nested attribute.

v2: use non-atomic __set_bit() (suggested by David Miller)

Signed-off-by: default avatarMichal Kubecek <mkubecek@suse.cz>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 0524399d

net/ethtool/bitset.c

+94 −0
Original line number Diff line number Diff line
@@ -588,6 +588,100 @@ int ethnl_update_bitset32(u32 *bitmap, unsigned int nbits, 
	return 0;

}



/**

 * ethnl_parse_bitset() - Compute effective value and mask from bitset nest

 * @val:     unsigned long based bitmap to put value into

 * @mask:    unsigned long based bitmap to put mask into

 * @nbits:   size of @val and @mask bitmaps

 * @attr:    nest attribute to parse and apply

 * @names:   array of bit names; may be null for compact format

 * @extack:  extack for error reporting

 *

 * Provide @nbits size long bitmaps for value and mask so that

 * x = (val & mask) | (x & ~mask) would modify any @nbits sized bitmap x

 * the same way ethnl_update_bitset() with the same bitset attribute would.

 *

 * Return:   negative error code on failure, 0 on success

 */

int ethnl_parse_bitset(unsigned long *val, unsigned long *mask,

		       unsigned int nbits, const struct nlattr *attr,

		       ethnl_string_array_t names,

		       struct netlink_ext_ack *extack)

{

	struct nlattr *tb[ETHTOOL_A_BITSET_MAX + 1];

	const struct nlattr *bit_attr;

	bool no_mask;

	int rem;

	int ret;



	if (!attr)

		return 0;

	ret = nla_parse_nested(tb, ETHTOOL_A_BITSET_MAX, attr, bitset_policy,

			       extack);

	if (ret < 0)

		return ret;

	no_mask = tb[ETHTOOL_A_BITSET_NOMASK];



	if (!tb[ETHTOOL_A_BITSET_BITS]) {

		unsigned int change_bits;



		ret = ethnl_compact_sanity_checks(nbits, attr, tb, extack);

		if (ret < 0)

			return ret;



		change_bits = nla_get_u32(tb[ETHTOOL_A_BITSET_SIZE]);

		bitmap_from_arr32(val, nla_data(tb[ETHTOOL_A_BITSET_VALUE]),

				  change_bits);

		if (change_bits < nbits)

			bitmap_clear(val, change_bits, nbits - change_bits);

		if (no_mask) {

			bitmap_fill(mask, nbits);

		} else {

			bitmap_from_arr32(mask,

					  nla_data(tb[ETHTOOL_A_BITSET_MASK]),

					  change_bits);

			if (change_bits < nbits)

				bitmap_clear(mask, change_bits,

					     nbits - change_bits);

		}



		return 0;

	}



	if (tb[ETHTOOL_A_BITSET_VALUE]) {

		NL_SET_ERR_MSG_ATTR(extack, tb[ETHTOOL_A_BITSET_VALUE],

				    "value only allowed in compact bitset");

		return -EINVAL;

	}

	if (tb[ETHTOOL_A_BITSET_MASK]) {

		NL_SET_ERR_MSG_ATTR(extack, tb[ETHTOOL_A_BITSET_MASK],

				    "mask only allowed in compact bitset");

		return -EINVAL;

	}



	bitmap_zero(val, nbits);

	if (no_mask)

		bitmap_fill(mask, nbits);

	else

		bitmap_zero(mask, nbits);



	nla_for_each_nested(bit_attr, tb[ETHTOOL_A_BITSET_BITS], rem) {

		unsigned int idx;

		bool bit_val;



		ret = ethnl_parse_bit(&idx, &bit_val, nbits, bit_attr, no_mask,

				      names, extack);

		if (ret < 0)

			return ret;

		if (bit_val)

			__set_bit(idx, val);

		if (!no_mask)

			__set_bit(idx, mask);

	}



	return 0;

}



#if BITS_PER_LONG == 64 && defined(__BIG_ENDIAN)



/* 64-bit big endian architectures are the only case when u32 based bitmaps

net/ethtool/bitset.h

+4 −0
Original line number Diff line number Diff line
@@ -26,5 +26,9 @@ int ethnl_update_bitset(unsigned long *bitmap, unsigned int nbits, 
int ethnl_update_bitset32(u32 *bitmap, unsigned int nbits,

			  const struct nlattr *attr, ethnl_string_array_t names,

			  struct netlink_ext_ack *extack, bool *mod);

int ethnl_parse_bitset(unsigned long *val, unsigned long *mask,

		       unsigned int nbits, const struct nlattr *attr,

		       ethnl_string_array_t names,

		       struct netlink_ext_ack *extack);



#endif /* _NET_ETHTOOL_BITSET_H */