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author | David S. Miller <davem@davemloft.net> | 2016-04-20 01:49:29 +0200 |
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committer | David S. Miller <davem@davemloft.net> | 2016-04-20 01:49:29 +0200 |
commit | 35c5845957c7982dac1f525ff3412f8acf0a0385 (patch) | |
tree | e27bce362485677d849a5924e9072a09692e4b83 /include/net/netlink.h | |
parent | net: Align IFLA_STATS64 attributes properly on architectures that need it. (diff) | |
download | linux-35c5845957c7982dac1f525ff3412f8acf0a0385.tar.xz linux-35c5845957c7982dac1f525ff3412f8acf0a0385.zip |
net: Add helpers for 64-bit aligning netlink attributes.
Suggested-by: Eric Dumazet <eric.dumazet@gmail.com>
Suggested-by: Nicolas Dichtel <nicolas.dichtel@6wind.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'include/net/netlink.h')
-rw-r--r-- | include/net/netlink.h | 37 |
1 files changed, 37 insertions, 0 deletions
diff --git a/include/net/netlink.h b/include/net/netlink.h index 0e3172751755..e644b3489acf 100644 --- a/include/net/netlink.h +++ b/include/net/netlink.h @@ -1231,6 +1231,43 @@ static inline int nla_validate_nested(const struct nlattr *start, int maxtype, } /** + * nla_align_64bit - 64-bit align the nla_data() of next attribute + * @skb: socket buffer the message is stored in + * @padattr: attribute type for the padding + * + * Conditionally emit a padding netlink attribute in order to make + * the next attribute we emit have a 64-bit aligned nla_data() area. + * This will only be done in architectures which do not have + * HAVE_EFFICIENT_UNALIGNED_ACCESS defined. + * + * Returns zero on success or a negative error code. + */ +static inline int nla_align_64bit(struct sk_buff *skb, int padattr) +{ +#ifndef HAVE_EFFICIENT_UNALIGNED_ACCESS + if (IS_ALIGNED((unsigned long)skb->data, 8)) { + struct nlattr *attr = nla_reserve(skb, padattr, 0); + if (!attr) + return -EMSGSIZE; + } +#endif + return 0; +} + +/** + * nla_total_size_64bit - total length of attribute including padding + * @payload: length of payload + */ +static inline int nla_total_size_64bit(int payload) +{ + return NLA_ALIGN(nla_attr_size(payload)) +#ifndef HAVE_EFFICIENT_UNALIGNED_ACCESS + + NLA_ALIGN(nla_attr_size(0)) +#endif + ; +} + +/** * nla_for_each_attr - iterate over a stream of attributes * @pos: loop counter, set to current attribute * @head: head of attribute stream |