[PATCH v2 net-next 1/5] tcp: add a helper to calculate size of opt_stats

[Wei Wang]

From: Wei Wang <wei...@google.com>

This is to refactor the calculation of the size of opt_stats to a helper
function to make the code cleaner and easier for later changes.

Suggested-by: Stephen Hemminger <step...@networkplumber.org>
Signed-off-by: Wei Wang <wei...@google.com>
Signed-off-by: Eric Dumazet <eduma...@google.com>
Acked-by: Neal Cardwell <ncardw...@google.com>
Acked-by: Soheil Hassas Yeganeh <soh...@google.com>
Acked-by: Yuchung Cheng <ych...@google.com>
---
 net/ipv4/tcp.c | 27 ++++++++++++++++++++++++---
 1 file changed, 24 insertions(+), 3 deletions(-)

diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c
index f3bfb9f29520..27bbe6a792b7 100644
--- a/net/ipv4/tcp.c
+++ b/net/ipv4/tcp.c
@@ -3205,6 +3205,29 @@ void tcp_get_info(struct sock *sk, struct tcp_info *info)
 }
 EXPORT_SYMBOL_GPL(tcp_get_info);
 
+static size_t tcp_opt_stats_get_size(void)
+{
+       return
+               nla_total_size_64bit(sizeof(u64)) + /* TCP_NLA_BUSY */
+               nla_total_size_64bit(sizeof(u64)) + /* TCP_NLA_RWND_LIMITED */
+               nla_total_size_64bit(sizeof(u64)) + /* TCP_NLA_SNDBUF_LIMITED */
+               nla_total_size_64bit(sizeof(u64)) + /* TCP_NLA_DATA_SEGS_OUT */
+               nla_total_size_64bit(sizeof(u64)) + /* TCP_NLA_TOTAL_RETRANS */
+               nla_total_size_64bit(sizeof(u64)) + /* TCP_NLA_PACING_RATE */
+               nla_total_size_64bit(sizeof(u64)) + /* TCP_NLA_DELIVERY_RATE */
+               nla_total_size(sizeof(u32)) + /* TCP_NLA_SND_CWND */
+               nla_total_size(sizeof(u32)) + /* TCP_NLA_REORDERING */
+               nla_total_size(sizeof(u32)) + /* TCP_NLA_MIN_RTT */
+               nla_total_size(sizeof(u8)) + /* TCP_NLA_RECUR_RETRANS */
+               nla_total_size(sizeof(u8)) + /* TCP_NLA_DELIVERY_RATE_APP_LMT */
+               nla_total_size(sizeof(u32)) + /* TCP_NLA_SNDQ_SIZE */
+               nla_total_size(sizeof(u8)) + /* TCP_NLA_CA_STATE */
+               nla_total_size(sizeof(u32)) + /* TCP_NLA_SND_SSTHRESH */
+               nla_total_size(sizeof(u32)) + /* TCP_NLA_DELIVERED */
+               nla_total_size(sizeof(u32)) + /* TCP_NLA_DELIVERED_CE */
+               0;
+}
+
 struct sk_buff *tcp_get_timestamping_opt_stats(const struct sock *sk)
 {
        const struct tcp_sock *tp = tcp_sk(sk);
@@ -3213,9 +3236,7 @@ struct sk_buff *tcp_get_timestamping_opt_stats(const 
struct sock *sk)
        u64 rate64;
        u32 rate;
 
-       stats = alloc_skb(7 * nla_total_size_64bit(sizeof(u64)) +
-                         7 * nla_total_size(sizeof(u32)) +
-                         3 * nla_total_size(sizeof(u8)), GFP_ATOMIC);
+       stats = alloc_skb(tcp_opt_stats_get_size(), GFP_ATOMIC);
        if (!stats)
                return NULL;
 
-- 
2.18.0.345.g5c9ce644c3-goog