From: Eric Dumazet <edumazet@google.com>
To: "David S . Miller" <davem@davemloft.net>,
Jakub Kicinski <kuba@kernel.org>,
Paolo Abeni <pabeni@redhat.com>
Cc: Simon Horman <horms@kernel.org>, Ido Schimmel <idosch@nvidia.com>,
David Ahern <dsahern@kernel.org>,
netdev@vger.kernel.org, eric.dumazet@gmail.com,
Eric Dumazet <edumazet@google.com>
Subject: [PATCH v2 net-next 2/2] ipv6: frags: cleanup __IP6_INC_STATS() confusion
Date: Tue, 26 May 2026 14:55:29 +0000 [thread overview]
Message-ID: <20260526145529.3587126-3-edumazet@google.com> (raw)
In-Reply-To: <20260526145529.3587126-1-edumazet@google.com>
After commits e1ae5c2ea478 ("vrf: Increment Icmp6InMsgs on the original
netdev") and bdb7cc643fc9 ("ipv6: Count interface receive statistics
on the ingress netdev") net/ipv6/reassembly.c uses three different
ways to reach idev in various __IP6_INC_STATS() calls.
- ip6_dst_idev(skb_dst(skb))
- __in6_dev_get_safely(skb->dev)
- __in6_dev_stats_get(skb->dev)
Lets centralize this from ipv6_frag_rcv() and use __in6_dev_stats_get().
Note that ipv6_frag_rcv() tests if skb->dev could be NULL already, so
I chose to also guard against NULL, but we probably can remove the
tests in a followup patch, because I do not think skb->dev could be NULL.
iif = skb->dev ? skb->dev->ifindex : 0;
idev can be NULL, __IP6_INC_STATS() deals with this possibility.
Small code size reduction as a bonus.
$ scripts/bloat-o-meter -t vmlinux.old vmlinux.new
add/remove: 0/0 grow/shrink: 0/2 up/down: 0/-145 (-145)
Function old new delta
ipv6_frag_rcv 2399 2362 -37
ip6_frag_reasm 705 597 -108
Total: Before=31455552, After=31455407, chg -0.00%
Signed-off-by: Eric Dumazet <edumazet@google.com>
---
net/ipv6/reassembly.c | 46 ++++++++++++++++++++-----------------------
1 file changed, 21 insertions(+), 25 deletions(-)
diff --git a/net/ipv6/reassembly.c b/net/ipv6/reassembly.c
index 11f9144bebbe2cf0152992c526fb6728f83f462d..05c51f669754a1a10e944bb7c4433565bcaacb40 100644
--- a/net/ipv6/reassembly.c
+++ b/net/ipv6/reassembly.c
@@ -69,7 +69,7 @@ static struct inet_frags ip6_frags;
static int ip6_frag_reasm(struct frag_queue *fq, struct sk_buff *skb,
struct sk_buff *prev_tail, struct net_device *dev,
- int *refs);
+ struct inet6_dev *idev, int *refs);
static void ip6_frag_expire(struct timer_list *t)
{
@@ -107,7 +107,8 @@ fq_find(struct net *net, __be32 id, const struct ipv6hdr *hdr, int iif)
static int ip6_frag_queue(struct net *net,
struct frag_queue *fq, struct sk_buff *skb,
struct frag_hdr *fhdr, int nhoff,
- u32 *prob_offset, int *refs)
+ u32 *prob_offset, int *refs,
+ struct inet6_dev *idev)
{
int offset, end, fragsize;
struct sk_buff *prev_tail;
@@ -133,8 +134,7 @@ static int ip6_frag_queue(struct net *net,
* we do not free it here.
*/
inet_frag_kill(&fq->q, refs);
- __IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)),
- IPSTATS_MIB_REASMFAILS);
+ __IP6_INC_STATS(net, idev, IPSTATS_MIB_REASMFAILS);
return -1;
}
@@ -167,8 +167,7 @@ static int ip6_frag_queue(struct net *net,
*/
*prob_offset = offsetof(struct ipv6hdr, payload_len);
inet_frag_kill(&fq->q, refs);
- __IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)),
- IPSTATS_MIB_REASMFAILS);
+ __IP6_INC_STATS(net, idev, IPSTATS_MIB_REASMFAILS);
return -1;
}
if (end > fq->q.len) {
@@ -227,7 +226,7 @@ static int ip6_frag_queue(struct net *net,
unsigned long orefdst = skb->_skb_refdst;
skb->_skb_refdst = 0UL;
- err = ip6_frag_reasm(fq, skb, prev_tail, dev, refs);
+ err = ip6_frag_reasm(fq, skb, prev_tail, dev, idev, refs);
skb->_skb_refdst = orefdst;
return err;
}
@@ -242,12 +241,10 @@ static int ip6_frag_queue(struct net *net,
goto err;
}
err = -EINVAL;
- __IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)),
- IPSTATS_MIB_REASM_OVERLAPS);
+ __IP6_INC_STATS(net, idev, IPSTATS_MIB_REASM_OVERLAPS);
discard_fq:
inet_frag_kill(&fq->q, refs);
- __IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)),
- IPSTATS_MIB_REASMFAILS);
+ __IP6_INC_STATS(net, idev, IPSTATS_MIB_REASMFAILS);
err:
kfree_skb_reason(skb, reason);
return err;
@@ -262,7 +259,7 @@ static int ip6_frag_queue(struct net *net,
*/
static int ip6_frag_reasm(struct frag_queue *fq, struct sk_buff *skb,
struct sk_buff *prev_tail, struct net_device *dev,
- int *refs)
+ struct inet6_dev *idev, int *refs)
{
struct net *net = fq->q.fqdir->net;
unsigned int nhoff;
@@ -311,7 +308,7 @@ static int ip6_frag_reasm(struct frag_queue *fq, struct sk_buff *skb,
skb_postpush_rcsum(skb, skb_network_header(skb),
skb_network_header_len(skb));
- __IP6_INC_STATS(net, __in6_dev_stats_get(dev, skb), IPSTATS_MIB_REASMOKS);
+ __IP6_INC_STATS(net, idev, IPSTATS_MIB_REASMOKS);
fq->q.rb_fragments = RB_ROOT;
fq->q.fragments_tail = NULL;
fq->q.last_run_head = NULL;
@@ -323,7 +320,7 @@ static int ip6_frag_reasm(struct frag_queue *fq, struct sk_buff *skb,
out_oom:
net_dbg_ratelimited("ip6_frag_reasm: no memory for reassembly\n");
out_fail:
- __IP6_INC_STATS(net, __in6_dev_stats_get(dev, skb), IPSTATS_MIB_REASMFAILS);
+ __IP6_INC_STATS(net, idev, IPSTATS_MIB_REASMFAILS);
inet_frag_kill(&fq->q, refs);
return -1;
}
@@ -332,15 +329,18 @@ static int ipv6_frag_rcv(struct sk_buff *skb)
{
const struct ipv6hdr *hdr = ipv6_hdr(skb);
struct net *net = skb_dst_dev_net(skb);
+ struct inet6_dev *idev;
struct frag_hdr *fhdr;
struct frag_queue *fq;
u8 nexthdr;
int iif;
+ idev = skb->dev ? __in6_dev_stats_get(skb->dev, skb) : NULL;
+
if (IP6CB(skb)->flags & IP6SKB_FRAGMENTED)
goto fail_hdr;
- __IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)), IPSTATS_MIB_REASMREQDS);
+ __IP6_INC_STATS(net, idev, IPSTATS_MIB_REASMREQDS);
/* Jumbo payload inhibits frag. header */
if (hdr->payload_len == 0)
@@ -356,8 +356,7 @@ static int ipv6_frag_rcv(struct sk_buff *skb)
if (!(fhdr->frag_off & htons(IP6_OFFSET | IP6_MF))) {
/* It is not a fragmented frame */
skb->transport_header += sizeof(struct frag_hdr);
- __IP6_INC_STATS(net,
- ip6_dst_idev(skb_dst(skb)), IPSTATS_MIB_REASMOKS);
+ __IP6_INC_STATS(net, idev, IPSTATS_MIB_REASMOKS);
IP6CB(skb)->nhoff = (u8 *)fhdr - skb_network_header(skb);
IP6CB(skb)->flags |= IP6SKB_FRAGMENTED;
@@ -374,8 +373,7 @@ static int ipv6_frag_rcv(struct sk_buff *skb)
*/
nexthdr = hdr->nexthdr;
if (ipv6frag_thdr_truncated(skb, skb_network_offset(skb) + sizeof(struct ipv6hdr), &nexthdr)) {
- __IP6_INC_STATS(net, __in6_dev_get_safely(skb->dev),
- IPSTATS_MIB_INHDRERRORS);
+ __IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS);
icmpv6_param_prob(skb, ICMPV6_HDR_INCOMP, 0);
return -1;
}
@@ -391,14 +389,13 @@ static int ipv6_frag_rcv(struct sk_buff *skb)
fq->iif = iif;
ret = ip6_frag_queue(net, fq, skb, fhdr, IP6CB(skb)->nhoff,
- &prob_offset, &refs);
+ &prob_offset, &refs, idev);
spin_unlock(&fq->q.lock);
rcu_read_unlock();
inet_frag_putn(&fq->q, refs);
if (prob_offset) {
- __IP6_INC_STATS(net, __in6_dev_get_safely(skb->dev),
- IPSTATS_MIB_INHDRERRORS);
+ __IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS);
/* icmpv6_param_prob() calls kfree_skb(skb) */
icmpv6_param_prob(skb, ICMPV6_HDR_FIELD, prob_offset);
}
@@ -406,13 +403,12 @@ static int ipv6_frag_rcv(struct sk_buff *skb)
}
rcu_read_unlock();
- __IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)), IPSTATS_MIB_REASMFAILS);
+ __IP6_INC_STATS(net, idev, IPSTATS_MIB_REASMFAILS);
kfree_skb(skb);
return -1;
fail_hdr:
- __IP6_INC_STATS(net, __in6_dev_get_safely(skb->dev),
- IPSTATS_MIB_INHDRERRORS);
+ __IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS);
icmpv6_param_prob(skb, ICMPV6_HDR_FIELD, skb_network_header_len(skb));
return -1;
}
--
2.54.0.746.g67dd491aae-goog
next prev parent reply other threads:[~2026-05-26 14:55 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-05-26 14:55 [PATCH v2 net-next 0/2] ipv6: frags: adopt __in6_dev_stats_get() a bit more Eric Dumazet
2026-05-26 14:55 ` [PATCH v2 net-next 1/2] ipv6: guard against possible NULL deref in __in6_dev_stats_get() Eric Dumazet
2026-05-27 7:44 ` Ido Schimmel
2026-05-26 14:55 ` Eric Dumazet [this message]
2026-05-27 7:44 ` [PATCH v2 net-next 2/2] ipv6: frags: cleanup __IP6_INC_STATS() confusion Ido Schimmel
2026-05-28 0:40 ` [PATCH v2 net-next 0/2] ipv6: frags: adopt __in6_dev_stats_get() a bit more patchwork-bot+netdevbpf
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