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| author | Eric Dumazet <edumazet@google.com> | 2014-09-18 08:02:05 -0700 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2014-09-22 14:21:47 -0400 |
| commit | 257117862634d89de33fec74858b1a0ba5ab444b (patch) | |
| tree | 799321753c9f5ac9358c708bced556df7e309772 /net/sched/sch_choke.c | |
| parent | 476c18850c6cbaa3f2bb661ae9710645081563b9 (diff) | |
| download | lwn-257117862634d89de33fec74858b1a0ba5ab444b.tar.gz lwn-257117862634d89de33fec74858b1a0ba5ab444b.zip | |
net: sched: shrink struct qdisc_skb_cb to 28 bytes
We cannot make struct qdisc_skb_cb bigger without impacting IPoIB,
or increasing skb->cb[] size.
Commit e0f31d849867 ("flow_keys: Record IP layer protocol in
skb_flow_dissect()") broke IPoIB.
Only current offender is sch_choke, and this one do not need an
absolutely precise flow key.
If we store 17 bytes of flow key, its more than enough. (Its the actual
size of flow_keys if it was a packed structure, but we might add new
fields at the end of it later)
Signed-off-by: Eric Dumazet <edumazet@google.com>
Fixes: e0f31d849867 ("flow_keys: Record IP layer protocol in skb_flow_dissect()")
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/sched/sch_choke.c')
| -rw-r--r-- | net/sched/sch_choke.c | 18 |
1 files changed, 14 insertions, 4 deletions
diff --git a/net/sched/sch_choke.c b/net/sched/sch_choke.c index ed30e436128b..fb666d1e4de3 100644 --- a/net/sched/sch_choke.c +++ b/net/sched/sch_choke.c @@ -133,10 +133,16 @@ static void choke_drop_by_idx(struct Qdisc *sch, unsigned int idx) --sch->q.qlen; } +/* private part of skb->cb[] that a qdisc is allowed to use + * is limited to QDISC_CB_PRIV_LEN bytes. + * As a flow key might be too large, we store a part of it only. + */ +#define CHOKE_K_LEN min_t(u32, sizeof(struct flow_keys), QDISC_CB_PRIV_LEN - 3) + struct choke_skb_cb { u16 classid; u8 keys_valid; - struct flow_keys keys; + u8 keys[QDISC_CB_PRIV_LEN - 3]; }; static inline struct choke_skb_cb *choke_skb_cb(const struct sk_buff *skb) @@ -163,22 +169,26 @@ static u16 choke_get_classid(const struct sk_buff *skb) static bool choke_match_flow(struct sk_buff *skb1, struct sk_buff *skb2) { + struct flow_keys temp; + if (skb1->protocol != skb2->protocol) return false; if (!choke_skb_cb(skb1)->keys_valid) { choke_skb_cb(skb1)->keys_valid = 1; - skb_flow_dissect(skb1, &choke_skb_cb(skb1)->keys); + skb_flow_dissect(skb1, &temp); + memcpy(&choke_skb_cb(skb1)->keys, &temp, CHOKE_K_LEN); } if (!choke_skb_cb(skb2)->keys_valid) { choke_skb_cb(skb2)->keys_valid = 1; - skb_flow_dissect(skb2, &choke_skb_cb(skb2)->keys); + skb_flow_dissect(skb2, &temp); + memcpy(&choke_skb_cb(skb2)->keys, &temp, CHOKE_K_LEN); } return !memcmp(&choke_skb_cb(skb1)->keys, &choke_skb_cb(skb2)->keys, - sizeof(struct flow_keys)); + CHOKE_K_LEN); } /* |