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Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni , Simon Horman , David Ahern , Abhishek Chauhan , Mina Almasry , Florian Westphal , Alexander Lobakin , David Howells , Jiri Pirko , Daniel Borkmann , Sebastian Andrzej Siewior , Lorenzo Bianconi , Pavel Begunkov , linux-kernel@vger.kernel.org, kernel-team@cloudflare.com, Jesper Dangaard Brouer Subject: [RFC v2 net-next 2/7] net: introduce sk_skb_reason_drop function Message-ID: <0cb76a7cc4fc9967ea901d5cb638d8c0e118e7bd.1717206060.git.yan@cloudflare.com> References: Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" Long used destructors kfree_skb and kfree_skb_reason do not pass receiving socket to packet drop tracepoints trace_kfree_skb. This makes it hard to track packet drops of a certain netns (container) or a socket (user application). The naming of these destructors are also not consistent with most sk/skb operating functions, i.e. functions named "sk_xxx" or "skb_xxx". Introduce a new functions sk_skb_reason_drop as drop-in replacement for kfree_skb_reason on local receiving path. Callers can now pass receiving sockets to the tracepoints. kfree_skb and kfree_skb_reason are still usable but they are now just inline helpers that call sk_skb_reason_drop. Note it is not feasible to do the same to consume_skb. Packets not dropped can flow through multiple receive handlers, and have multiple receiving sockets. Leave it untouched for now. Suggested-by: Eric Dumazet Signed-off-by: Yan Zhai --- v1->v2: changes function names to be more consistent with common sk/skb operations --- include/linux/skbuff.h | 10 ++++++++-- net/core/skbuff.c | 22 ++++++++++++---------- 2 files changed, 20 insertions(+), 12 deletions(-) diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h index fe7d8dbef77e..c479a2515a62 100644 --- a/include/linux/skbuff.h +++ b/include/linux/skbuff.h @@ -1251,8 +1251,14 @@ static inline bool skb_data_unref(const struct sk_bu= ff *skb, return true; } =20 -void __fix_address -kfree_skb_reason(struct sk_buff *skb, enum skb_drop_reason reason); +void __fix_address sk_skb_reason_drop(struct sock *sk, struct sk_buff *skb, + enum skb_drop_reason reason); + +static inline void +kfree_skb_reason(struct sk_buff *skb, enum skb_drop_reason reason) +{ + sk_skb_reason_drop(NULL, skb, reason); +} =20 /** * kfree_skb - free an sk_buff with 'NOT_SPECIFIED' reason diff --git a/net/core/skbuff.c b/net/core/skbuff.c index 2854afdd713f..9def11fe42c4 100644 --- a/net/core/skbuff.c +++ b/net/core/skbuff.c @@ -1190,7 +1190,8 @@ void __kfree_skb(struct sk_buff *skb) EXPORT_SYMBOL(__kfree_skb); =20 static __always_inline -bool __kfree_skb_reason(struct sk_buff *skb, enum skb_drop_reason reason) +bool __sk_skb_reason_drop(struct sock *sk, struct sk_buff *skb, + enum skb_drop_reason reason) { if (unlikely(!skb_unref(skb))) return false; @@ -1203,26 +1204,27 @@ bool __kfree_skb_reason(struct sk_buff *skb, enum s= kb_drop_reason reason) if (reason =3D=3D SKB_CONSUMED) trace_consume_skb(skb, __builtin_return_address(0)); else - trace_kfree_skb(skb, __builtin_return_address(0), reason, NULL); + trace_kfree_skb(skb, __builtin_return_address(0), reason, sk); return true; } =20 /** - * kfree_skb_reason - free an sk_buff with special reason + * sk_skb_reason_drop - free an sk_buff with special reason + * @sk: the socket to receive @skb, or NULL if not applicable * @skb: buffer to free * @reason: reason why this skb is dropped * - * Drop a reference to the buffer and free it if the usage count has - * hit zero. Meanwhile, pass the drop reason to 'kfree_skb' - * tracepoint. + * Drop a reference to the buffer and free it if the usage count has hit + * zero. Meanwhile, pass the receiving socket and drop reason to + * 'kfree_skb' tracepoint. */ void __fix_address -kfree_skb_reason(struct sk_buff *skb, enum skb_drop_reason reason) +sk_skb_reason_drop(struct sock *sk, struct sk_buff *skb, enum skb_drop_rea= son reason) { - if (__kfree_skb_reason(skb, reason)) + if (__sk_skb_reason_drop(sk, skb, reason)) __kfree_skb(skb); } -EXPORT_SYMBOL(kfree_skb_reason); +EXPORT_SYMBOL(sk_skb_reason_drop); =20 #define KFREE_SKB_BULK_SIZE 16 =20 @@ -1261,7 +1263,7 @@ kfree_skb_list_reason(struct sk_buff *segs, enum skb_= drop_reason reason) while (segs) { struct sk_buff *next =3D segs->next; =20 - if (__kfree_skb_reason(segs, reason)) { + if (__sk_skb_reason_drop(NULL, segs, reason)) { skb_poison_list(segs); kfree_skb_add_bulk(segs, &sa, reason); } --=20 2.30.2