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

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
......@@ -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
......
......@@ -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 */
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