act_mirred: don't clone skb when skb isn't shared
Subsystems (3)
PATCH v2 1/1 act_mirred: don't clone skb when skb isn't shared
don't clone skb when skb isn't shared
When the tcf_action is TC_ACT_STOLEN, and the skb isn't shared, we don't need to clone a new skb. As the skb will be freed after this function returns, we can use it freely once we get a reference to it.
----
include/net/sch_generic.h | 11 +++++++++-- net/sched/act_mirred.c | 6 +++--- 2 files changed, 12 insertions(+), 5 deletions(-)
include/net/sch_generic.h +9 -2
@@ -571,9 +571,16 @@ static inline u32 qdisc_l2t(struct qdisc_rate_table* rtab, unsigned int pktlen) }#ifdef CONFIG_NET_CLS_ACT -static inline struct sk_buff *skb_act_clone (struct sk_buff *skb,gfp_t gfp_mask) +static inline struct sk_buff *skb_act_clone (struct sk_buff *skb,gfp_t gfp_mask, +int action) { -struct sk_buff *n =skb_clone (skb, gfp_mask); +struct sk_buff *n; + +if ((action ==TC_ACT_SHOT || action ==TC_ACT_STOLEN || + action ==TC_ACT_QUEUED ) && !skb_shared (skb)) + n =skb_get (skb); +else + n =skb_clone (skb, gfp_mask);if (n) { n->tc_verd =SET_TC_VERD (n->tc_verd,0 );
net/sched/act_mirred.c +3 -3
@@ -169,13 +169,13 @@ static int tcf_mirred(struct sk_buff *skb, struct tc_action *a, goto out; } - skb2 =skb_act_clone (skb,GFP_ATOMIC ); + at =G_TC_AT (skb->tc_verd); + skb2 =skb_act_clone (skb,GFP_ATOMIC , m->tcf_action);if (skb2 ==NULL ) goto out; m->tcf_bstats.bytes +=qdisc_pkt_len (skb2); m->tcf_bstats.packets++; - at =G_TC_AT (skb->tc_verd);if (!(at &AT_EGRESS )) {if (m->tcfm_ok_push)skb_push (skb2, skb2->dev->hard_header_len);
@@ -185,8 +185,8 @@ static int tcf_mirred(struct sk_buff *skb, struct tc_action *a,if (m->tcfm_eaction !=TCA_EGRESS_MIRROR ) skb2->tc_verd =SET_TC_FROM (skb2->tc_verd, at); - skb2->dev = dev; skb2->skb_iif = skb->dev->ifindex; + skb2->dev = dev;dev_queue_xmit (skb2); err =0 ;
include/net/sch_generic.h static inline u32 qdisc_l2t(struct qdisc_rate_table* rtab, unsigned int pktlen) · line 579
Quoted 1 line · Changli Gao
include/net/sch_generic.h +1
-0+ if ((action == TC_ACT_SHOT || action == TC_ACT_STOLEN ||
I am not so sure about SHOT; the other two are fine.
net/sched/act_mirred.c static int tcf_mirred(struct sk_buff *skb, struct tc_action *a, · line 172
Quoted 2 lines
net/sched/act_mirred.c +1
-1- skb2 =skb_act_clone (skb,GFP_ATOMIC ); + at =G_TC_AT (skb->tc_verd);
Was there any need to move above line?
net/sched/act_mirred.c static int tcf_mirred(struct sk_buff *skb, struct tc_action *a,
Quoted 4 lines
net/sched/act_mirred.c +1
-1+ skb2 =skb_act_clone (skb,GFP_ATOMIC , m->tcf_action); - skb2->dev = dev;
Or this one?
net/sched/act_mirred.c static int tcf_mirred(struct sk_buff *skb, struct tc_action *a, · line 189
Quoted 2 lines
net/sched/act_mirred.c +1
-0skb2->skb_iif = skb->dev->ifindex; + skb2->dev = dev;
cheers,
jamal
Quoted 5 lines · jamal
Quoted 1 line · Changli Gao
+ if ((action ==
TC_ACT_SHOT|| action ==TC_ACT_STOLEN||I am not so sure about SHOT; the other two are fine.
It is unlikely that this function will be called with TC_ACT_SHOT. In fact, this function has only one user act_mirred. Should we remove this flag, or keep STOLEN flag only?
Quoted 5 lines
Quoted 3 lines
- skb2 =
skb_act_clone(skb, GFP_ATOMIC);
+ at =G_TC_AT(skb->tc_verd);Was there any need to move above line?
skb2 maybe skb, and its tc_verd maybe mangled in skb_act_clone(), so I move it up.
Quoted 11 lines
Quoted 5 lines
+ skb2 =
skb_act_clone(skb, GFP_ATOMIC, m->tcf_action);-
skb2->dev= dev;Or this one?
Quoted 2 lines
skb2->skb_iif=skb->dev->ifindex;
+skb2->dev= dev;
the same reason as above. skb2 and skb maybe the same. If we don't move lines, skb->dev maybe over written.
Signature · 2 lines
Regards, Changli Gao([email protected])