[v2,net-next,3/4] inet: frags: change inet_frag_kill() to defer refcount updates

Message ID	20250312082250.1803501-4-edumazet@google.com (mailing list archive)
State	New
Delegated to:	Netdev Maintainers
Headers	show Received: from mail-qv1-f73.google.com (mail-qv1-f73.google.com [209.85.219.73]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 05364234988 for <netdev@vger.kernel.org>; Wed, 12 Mar 2025 08:22:58 +0000 (UTC) Date: Wed, 12 Mar 2025 08:22:49 +0000 In-Reply-To: <20250312082250.1803501-1-edumazet@google.com> Precedence: bulk Mime-Version: 1.0 References: <20250312082250.1803501-1-edumazet@google.com> Message-ID: <20250312082250.1803501-4-edumazet@google.com> Subject: [PATCH v2 net-next 3/4] inet: frags: change inet_frag_kill() to defer refcount updates From: Eric Dumazet <edumazet@google.com> To: "David S . Miller" <davem@davemloft.net>, Jakub Kicinski <kuba@kernel.org>, Paolo Abeni <pabeni@redhat.com> Cc: David Ahern <dsahern@kernel.org>, Simon Horman <horms@kernel.org>, netdev@vger.kernel.org, eric.dumazet@gmail.com, Eric Dumazet <edumazet@google.com> Content-Type: text/plain; charset="UTF-8"
Series	inet: frags: fully use RCU \| expand [v2,net-next,0/4] inet: frags: fully use RCU [v2,net-next,1/4] inet: frags: add inet_frag_putn() helper [v2,net-next,2/4] ipv4: frags: remove ipq_put() [v2,net-next,3/4] inet: frags: change inet_frag_kill() to defer refcount updates [v2,net-next,4/4] inet: frags: save a pair of atomic operations in reassembly

Context	Check	Description
netdev/series_format	success	Posting correctly formatted
netdev/tree_selection	success	Clearly marked for net-next
netdev/ynl	success	Generated files up to date; no warnings/errors; no diff in generated;
netdev/fixes_present	success	Fixes tag not required for -next series
netdev/header_inline	success	No static functions without inline keyword in header files
netdev/build_32bit	success	Errors and warnings before: 38 this patch: 38
netdev/build_tools	success	Errors and warnings before: 26 (+0) this patch: 26 (+0)
netdev/cc_maintainers	warning	9 maintainers not CCed: coreteam@netfilter.org netfilter-devel@vger.kernel.org alex.aring@gmail.com linux-wpan@vger.kernel.org miquel.raynal@bootlin.com pablo@netfilter.org kadlec@netfilter.org martin.lau@kernel.org stefan@datenfreihafen.org
netdev/build_clang	success	Errors and warnings before: 73 this patch: 73
netdev/verify_signedoff	success	Signed-off-by tag matches author and committer
netdev/deprecated_api	success	None detected
netdev/check_selftest	success	No net selftest shell script
netdev/verify_fixes	success	No Fixes tag
netdev/build_allmodconfig_warn	success	Errors and warnings before: 4243 this patch: 4243
netdev/checkpatch	success	total: 0 errors, 0 warnings, 0 checks, 337 lines checked
netdev/build_clang_rust	success	No Rust files in patch. Skipping build
netdev/kdoc	success	Errors and warnings before: 0 this patch: 0
netdev/source_inline	success	Was 0 now: 0
netdev/contest	success	net-next-2025-03-13--00-00 (tests: 894)

diff --git a/include/net/inet_frag.h b/include/net/inet_frag.h index 26687ad0b14142e904b66acee4c98537fa8077c3..0eccd9c3a883fbceb9a0a740237b7245f13c5d26 100644 --- a/include/net/inet_frag.h +++ b/include/net/inet_frag.h @@ -137,7 +137,7 @@ static inline void fqdir_pre_exit(struct fqdir *fqdir) } void fqdir_exit(struct fqdir *fqdir); -void inet_frag_kill(struct inet_frag_queue *q); +void inet_frag_kill(struct inet_frag_queue *q, int *refs); void inet_frag_destroy(struct inet_frag_queue *q); struct inet_frag_queue *inet_frag_find(struct fqdir *fqdir, void *key); diff --git a/include/net/ipv6_frag.h b/include/net/ipv6_frag.h index 9d968d7d9fa402a4dd5e0f3d458bacbdcd49da77..38ef66826939ee561e409f528292ca4af1e29a3b 100644 --- a/include/net/ipv6_frag.h +++ b/include/net/ipv6_frag.h @@ -78,7 +78,7 @@ ip6frag_expire_frag_queue(struct net *net, struct frag_queue *fq) goto out; fq->q.flags |= INET_FRAG_DROP; - inet_frag_kill(&fq->q); + inet_frag_kill(&fq->q, &refs); dev = dev_get_by_index_rcu(net, fq->iif); if (!dev) diff --git a/net/ieee802154/6lowpan/reassembly.c b/net/ieee802154/6lowpan/reassembly.c index 2df1a027e68a1a839388ba088d2fb49a10914f91..c5f86cff06ee7f95556955f994b859c86a315646 100644 --- a/net/ieee802154/6lowpan/reassembly.c +++ b/net/ieee802154/6lowpan/reassembly.c @@ -31,7 +31,8 @@ static const char lowpan_frags_cache_name[] = "lowpan-frags"; static struct inet_frags lowpan_frags; static int lowpan_frag_reasm(struct lowpan_frag_queue *fq, struct sk_buff *skb, - struct sk_buff *prev, struct net_device *ldev); + struct sk_buff *prev, struct net_device *ldev, + int *refs); static void lowpan_frag_init(struct inet_frag_queue *q, const void *a) { @@ -54,7 +55,7 @@ static void lowpan_frag_expire(struct timer_list *t) if (fq->q.flags & INET_FRAG_COMPLETE) goto out; - inet_frag_kill(&fq->q); + inet_frag_kill(&fq->q, &refs); out: spin_unlock(&fq->q.lock); inet_frag_putn(&fq->q, refs); @@ -83,7 +84,8 @@ fq_find(struct net *net, const struct lowpan_802154_cb *cb, } static int lowpan_frag_queue(struct lowpan_frag_queue *fq, - struct sk_buff *skb, u8 frag_type) + struct sk_buff *skb, u8 frag_type, + int *refs) { struct sk_buff *prev_tail; struct net_device *ldev; @@ -144,7 +146,7 @@ static int lowpan_frag_queue(struct lowpan_frag_queue *fq, unsigned long orefdst = skb->_skb_refdst; skb->_skb_refdst = 0UL; - res = lowpan_frag_reasm(fq, skb, prev_tail, ldev); + res = lowpan_frag_reasm(fq, skb, prev_tail, ldev, refs); skb->_skb_refdst = orefdst; return res; } @@ -163,11 +165,12 @@ static int lowpan_frag_queue(struct lowpan_frag_queue *fq, * the last and the first frames arrived and all the bits are here. */ static int lowpan_frag_reasm(struct lowpan_frag_queue *fq, struct sk_buff *skb, - struct sk_buff *prev_tail, struct net_device *ldev) + struct sk_buff *prev_tail, struct net_device *ldev, + int *refs) { void *reasm_data; - inet_frag_kill(&fq->q); + inet_frag_kill(&fq->q, refs); reasm_data = inet_frag_reasm_prepare(&fq->q, skb, prev_tail); if (!reasm_data) @@ -306,7 +309,7 @@ int lowpan_frag_rcv(struct sk_buff *skb, u8 frag_type) int ret, refs = 1; spin_lock(&fq->q.lock); - ret = lowpan_frag_queue(fq, skb, frag_type); + ret = lowpan_frag_queue(fq, skb, frag_type, &refs); spin_unlock(&fq->q.lock); inet_frag_putn(&fq->q, refs); diff --git a/net/ipv4/inet_fragment.c b/net/ipv4/inet_fragment.c index efc4cbee04c272b1afaf5f2d63b11040c22c11e5..5eb18605001387e7f23b8661dc9f24a533ab1600 100644 --- a/net/ipv4/inet_fragment.c +++ b/net/ipv4/inet_fragment.c @@ -225,10 +225,10 @@ void fqdir_exit(struct fqdir *fqdir) } EXPORT_SYMBOL(fqdir_exit); -void inet_frag_kill(struct inet_frag_queue *fq) +void inet_frag_kill(struct inet_frag_queue *fq, int *refs) { if (del_timer(&fq->timer)) - refcount_dec(&fq->refcnt); + (*refs)++; if (!(fq->flags & INET_FRAG_COMPLETE)) { struct fqdir *fqdir = fq->fqdir; @@ -243,7 +243,7 @@ void inet_frag_kill(struct inet_frag_queue *fq) if (!READ_ONCE(fqdir->dead)) { rhashtable_remove_fast(&fqdir->rhashtable, &fq->node, fqdir->f->rhash_params); - refcount_dec(&fq->refcnt); + (*refs)++; } else { fq->flags |= INET_FRAG_HASH_DEAD; } @@ -349,9 +349,11 @@ static struct inet_frag_queue *inet_frag_create(struct fqdir *fqdir, *prev = rhashtable_lookup_get_insert_key(&fqdir->rhashtable, &q->key, &q->node, f->rhash_params); if (*prev) { + int refs = 2; + q->flags |= INET_FRAG_COMPLETE; - inet_frag_kill(q); - inet_frag_destroy(q); + inet_frag_kill(q, &refs); + inet_frag_putn(q, refs); return NULL; } return q; diff --git a/net/ipv4/ip_fragment.c b/net/ipv4/ip_fragment.c index ee953be49b34dd63443e5621e7c2f2b61cf7d914..c5f3c810706fb328c3d8a4d8501424df0dceaa8e 100644 --- a/net/ipv4/ip_fragment.c +++ b/net/ipv4/ip_fragment.c @@ -76,7 +76,8 @@ static u8 ip4_frag_ecn(u8 tos) static struct inet_frags ip4_frags; static int ip_frag_reasm(struct ipq *qp, struct sk_buff *skb, - struct sk_buff *prev_tail, struct net_device *dev); + struct sk_buff *prev_tail, struct net_device *dev, + int *refs); static void ip4_frag_init(struct inet_frag_queue *q, const void *a) @@ -107,14 +108,6 @@ static void ip4_frag_free(struct inet_frag_queue *q) inet_putpeer(qp->peer); } -/* Kill ipq entry. It is not destroyed immediately, - * because caller (and someone more) holds reference count. - */ -static void ipq_kill(struct ipq *ipq) -{ - inet_frag_kill(&ipq->q); -} - static bool frag_expire_skip_icmp(u32 user) { return user == IP_DEFRAG_AF_PACKET || @@ -152,7 +145,7 @@ static void ip_expire(struct timer_list *t) goto out; qp->q.flags |= INET_FRAG_DROP; - ipq_kill(qp); + inet_frag_kill(&qp->q, &refs); __IP_INC_STATS(net, IPSTATS_MIB_REASMFAILS); __IP_INC_STATS(net, IPSTATS_MIB_REASMTIMEOUT); @@ -271,7 +264,7 @@ static int ip_frag_reinit(struct ipq *qp) } /* Add new segment to existing queue. */ -static int ip_frag_queue(struct ipq *qp, struct sk_buff *skb) +static int ip_frag_queue(struct ipq *qp, struct sk_buff *skb, int *refs) { struct net *net = qp->q.fqdir->net; int ihl, end, flags, offset; @@ -291,7 +284,7 @@ static int ip_frag_queue(struct ipq *qp, struct sk_buff *skb) if (!(IPCB(skb)->flags & IPSKB_FRAG_COMPLETE) && unlikely(ip_frag_too_far(qp)) && unlikely(err = ip_frag_reinit(qp))) { - ipq_kill(qp); + inet_frag_kill(&qp->q, refs); goto err; } @@ -375,10 +368,10 @@ static int ip_frag_queue(struct ipq *qp, struct sk_buff *skb) unsigned long orefdst = skb->_skb_refdst; skb->_skb_refdst = 0UL; - err = ip_frag_reasm(qp, skb, prev_tail, dev); + err = ip_frag_reasm(qp, skb, prev_tail, dev, refs); skb->_skb_refdst = orefdst; if (err) - inet_frag_kill(&qp->q); + inet_frag_kill(&qp->q, refs); return err; } @@ -395,7 +388,7 @@ static int ip_frag_queue(struct ipq *qp, struct sk_buff *skb) err = -EINVAL; __IP_INC_STATS(net, IPSTATS_MIB_REASM_OVERLAPS); discard_qp: - inet_frag_kill(&qp->q); + inet_frag_kill(&qp->q, refs); __IP_INC_STATS(net, IPSTATS_MIB_REASMFAILS); err: kfree_skb_reason(skb, reason); @@ -409,7 +402,8 @@ static bool ip_frag_coalesce_ok(const struct ipq *qp) /* Build a new IP datagram from all its fragments. */ static int ip_frag_reasm(struct ipq *qp, struct sk_buff *skb, - struct sk_buff *prev_tail, struct net_device *dev) + struct sk_buff *prev_tail, struct net_device *dev, + int *refs) { struct net *net = qp->q.fqdir->net; struct iphdr *iph; @@ -417,7 +411,7 @@ static int ip_frag_reasm(struct ipq *qp, struct sk_buff *skb, int len, err; u8 ecn; - ipq_kill(qp); + inet_frag_kill(&qp->q, refs); ecn = ip_frag_ecn_table[qp->ecn]; if (unlikely(ecn == 0xff)) { @@ -495,7 +489,7 @@ int ip_defrag(struct net *net, struct sk_buff *skb, u32 user) spin_lock(&qp->q.lock); - ret = ip_frag_queue(qp, skb); + ret = ip_frag_queue(qp, skb, &refs); spin_unlock(&qp->q.lock); inet_frag_putn(&qp->q, refs); diff --git a/net/ipv6/netfilter/nf_conntrack_reasm.c b/net/ipv6/netfilter/nf_conntrack_reasm.c index fcf969f9fe2ab57b9bdb30434b933b863e3d3369..f33acb730dc5807205811c2675efd27a9ee99222 100644 --- a/net/ipv6/netfilter/nf_conntrack_reasm.c +++ b/net/ipv6/netfilter/nf_conntrack_reasm.c @@ -123,7 +123,8 @@ static void __net_exit nf_ct_frags6_sysctl_unregister(struct net *net) #endif static int nf_ct_frag6_reasm(struct frag_queue *fq, struct sk_buff *skb, - struct sk_buff *prev_tail, struct net_device *dev); + struct sk_buff *prev_tail, struct net_device *dev, + int *refs); static inline u8 ip6_frag_ecn(const struct ipv6hdr *ipv6h) { @@ -167,7 +168,8 @@ static struct frag_queue *fq_find(struct net *net, __be32 id, u32 user, static int nf_ct_frag6_queue(struct frag_queue *fq, struct sk_buff *skb, - const struct frag_hdr *fhdr, int nhoff) + const struct frag_hdr *fhdr, int nhoff, + int *refs) { unsigned int payload_len; struct net_device *dev; @@ -221,7 +223,7 @@ static int nf_ct_frag6_queue(struct frag_queue *fq, struct sk_buff *skb, * this case. -DaveM */ pr_debug("end of fragment not rounded to 8 bytes.\n"); - inet_frag_kill(&fq->q); + inet_frag_kill(&fq->q, refs); return -EPROTO; } if (end > fq->q.len) { @@ -287,7 +289,7 @@ static int nf_ct_frag6_queue(struct frag_queue *fq, struct sk_buff *skb, unsigned long orefdst = skb->_skb_refdst; skb->_skb_refdst = 0UL; - err = nf_ct_frag6_reasm(fq, skb, prev, dev); + err = nf_ct_frag6_reasm(fq, skb, prev, dev, refs); skb->_skb_refdst = orefdst; /* After queue has assumed skb ownership, only 0 or @@ -301,7 +303,7 @@ static int nf_ct_frag6_queue(struct frag_queue *fq, struct sk_buff *skb, return -EINPROGRESS; insert_error: - inet_frag_kill(&fq->q); + inet_frag_kill(&fq->q, refs); err: skb_dst_drop(skb); return -EINVAL; @@ -315,13 +317,14 @@ static int nf_ct_frag6_queue(struct frag_queue *fq, struct sk_buff *skb, * the last and the first frames arrived and all the bits are here. */ static int nf_ct_frag6_reasm(struct frag_queue *fq, struct sk_buff *skb, - struct sk_buff *prev_tail, struct net_device *dev) + struct sk_buff *prev_tail, struct net_device *dev, + int *refs) { void *reasm_data; int payload_len; u8 ecn; - inet_frag_kill(&fq->q); + inet_frag_kill(&fq->q, refs); ecn = ip_frag_ecn_table[fq->ecn]; if (unlikely(ecn == 0xff)) @@ -372,7 +375,7 @@ static int nf_ct_frag6_reasm(struct frag_queue *fq, struct sk_buff *skb, return 0; err: - inet_frag_kill(&fq->q); + inet_frag_kill(&fq->q, refs); return -EINVAL; } @@ -483,7 +486,7 @@ int nf_ct_frag6_gather(struct net *net, struct sk_buff *skb, u32 user) spin_lock_bh(&fq->q.lock); - ret = nf_ct_frag6_queue(fq, skb, fhdr, nhoff); + ret = nf_ct_frag6_queue(fq, skb, fhdr, nhoff, &refs); if (ret == -EPROTO) { skb->transport_header = savethdr; ret = 0; diff --git a/net/ipv6/reassembly.c b/net/ipv6/reassembly.c index 5d56a8e5166bcb3a5a169a95029bc14180ef9323..7560380bd5871217d476f2e0e39332926c458bc1 100644 --- a/net/ipv6/reassembly.c +++ b/net/ipv6/reassembly.c @@ -68,7 +68,8 @@ static u8 ip6_frag_ecn(const struct ipv6hdr *ipv6h) 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); + struct sk_buff *prev_tail, struct net_device *dev, + int *refs); static void ip6_frag_expire(struct timer_list *t) { @@ -105,7 +106,7 @@ fq_find(struct net *net, __be32 id, const struct ipv6hdr *hdr, int iif) static int ip6_frag_queue(struct frag_queue *fq, struct sk_buff *skb, struct frag_hdr *fhdr, int nhoff, - u32 *prob_offset) + u32 *prob_offset, int *refs) { struct net *net = dev_net(skb_dst(skb)->dev); int offset, end, fragsize; @@ -220,7 +221,7 @@ static int ip6_frag_queue(struct frag_queue *fq, struct sk_buff *skb, unsigned long orefdst = skb->_skb_refdst; skb->_skb_refdst = 0UL; - err = ip6_frag_reasm(fq, skb, prev_tail, dev); + err = ip6_frag_reasm(fq, skb, prev_tail, dev, refs); skb->_skb_refdst = orefdst; return err; } @@ -238,7 +239,7 @@ static int ip6_frag_queue(struct frag_queue *fq, struct sk_buff *skb, __IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)), IPSTATS_MIB_REASM_OVERLAPS); discard_fq: - inet_frag_kill(&fq->q); + inet_frag_kill(&fq->q, refs); __IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)), IPSTATS_MIB_REASMFAILS); err: @@ -254,7 +255,8 @@ static int ip6_frag_queue(struct frag_queue *fq, struct sk_buff *skb, * the last and the first frames arrived and all the bits are here. */ static int ip6_frag_reasm(struct frag_queue *fq, struct sk_buff *skb, - struct sk_buff *prev_tail, struct net_device *dev) + struct sk_buff *prev_tail, struct net_device *dev, + int *refs) { struct net *net = fq->q.fqdir->net; unsigned int nhoff; @@ -262,7 +264,7 @@ static int ip6_frag_reasm(struct frag_queue *fq, struct sk_buff *skb, int payload_len; u8 ecn; - inet_frag_kill(&fq->q); + inet_frag_kill(&fq->q, refs); ecn = ip_frag_ecn_table[fq->ecn]; if (unlikely(ecn == 0xff)) @@ -320,7 +322,7 @@ static int ip6_frag_reasm(struct frag_queue *fq, struct sk_buff *skb, rcu_read_lock(); __IP6_INC_STATS(net, __in6_dev_stats_get(dev, skb), IPSTATS_MIB_REASMFAILS); rcu_read_unlock(); - inet_frag_kill(&fq->q); + inet_frag_kill(&fq->q, refs); return -1; } @@ -386,7 +388,7 @@ static int ipv6_frag_rcv(struct sk_buff *skb) fq->iif = iif; ret = ip6_frag_queue(fq, skb, fhdr, IP6CB(skb)->nhoff, - &prob_offset); + &prob_offset, &refs); spin_unlock(&fq->q.lock); inet_frag_putn(&fq->q, refs);

[v2,net-next,3/4] inet: frags: change inet_frag_kill() to defer refcount updates

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