From patchwork Fri Dec 6 12:11:01 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Paolo Abeni X-Patchwork-Id: 13897110 X-Patchwork-Delegate: matthieu.baerts@tessares.net Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.129.124]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id AD11E1FF7A1 for ; Fri, 6 Dec 2024 12:11:08 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=170.10.129.124 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1733487070; cv=none; b=ZSDZJeu1tGcIhlWVBJ1WjxZkqBwol/Se4dCIvZN/fxzaFle5WlHn6wSLXD62PsAlGWrRM1UtCbd1evVl3TX9JWWDvwlP6LSVGtuKq3aX7qEqjrAXcNzIsA+hyq/TGBLSINRrfUKeSVbUlUYOcFQXK0pQkzhEZwXsrNroCWdhtL4= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1733487070; c=relaxed/simple; bh=q8kT0ilAN4Jxf7TTMd/mGbup5Y7SM0eBbpdHdo+WiC4=; h=From:To:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version:content-type; b=oLmCSP2KjEF7vBEAeCYVvTMr7octOs6y4LMm1As8l0GoHsL2MtlE7G/+TLJT++//GzG+nbfFWOldGLtZ7hUYtLFpbSvnm0TnsyMZ4LRIhfvc44l9FEh2TjziLh1jXrbagSRLh12uidXZQAHgnr9MzXBrm58eZeJJdq0TNIuu9JE= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=redhat.com; spf=pass smtp.mailfrom=redhat.com; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b=Wtcsfn7O; arc=none smtp.client-ip=170.10.129.124 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=redhat.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=redhat.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="Wtcsfn7O" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1733487067; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=mKPGNuV23Yjj2+7zpNuZAaxI1QusZJAmixlLGMnNB50=; b=Wtcsfn7OlF78CXgAfrBUb2OhvlGPUhj1sJWAi0XltzEChWnrQNEH+LkCWE113HQ7Gqnsqb 6tszL1AiLLIjH0OYgcuyjwZrJ/BSkoS3UHBs331g77rDzmrnHXGpvtC0lIRAiNneeS5lsG vC2TXiQ9dC4ivcythnPr4E7TjYPACYs= Received: from mx-prod-mc-05.mail-002.prod.us-west-2.aws.redhat.com (ec2-54-186-198-63.us-west-2.compute.amazonaws.com [54.186.198.63]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-213-Ty0YH1ARPgGPT3YkLy7tXA-1; Fri, 06 Dec 2024 07:11:06 -0500 X-MC-Unique: Ty0YH1ARPgGPT3YkLy7tXA-1 X-Mimecast-MFC-AGG-ID: Ty0YH1ARPgGPT3YkLy7tXA Received: from mx-prod-int-04.mail-002.prod.us-west-2.aws.redhat.com (mx-prod-int-04.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.40]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by mx-prod-mc-05.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id 5C86F19560A3 for ; Fri, 6 Dec 2024 12:11:05 +0000 (UTC) Received: from gerbillo.redhat.com (unknown [10.39.192.243]) by mx-prod-int-04.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTP id 8F1831955F3F for ; Fri, 6 Dec 2024 12:11:04 +0000 (UTC) From: Paolo Abeni To: mptcp@lists.linux.dev Subject: [PATCH mptcp-next v2 5/7] mptcp: move the whole rx path under msk socket lock protection Date: Fri, 6 Dec 2024 13:11:01 +0100 Message-ID: In-Reply-To: References: Precedence: bulk X-Mailing-List: mptcp@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Scanned-By: MIMEDefang 3.0 on 10.30.177.40 X-Mimecast-Spam-Score: 0 X-Mimecast-MFC-PROC-ID: Bal3So4AVH40MC0NMVITWDS9svURUZ19Qcyq1pCr6E0_1733487065 X-Mimecast-Originator: redhat.com content-type: text/plain; charset="US-ASCII"; x-default=true After commit c2e6048fa1cf ("mptcp: fix race in release_cb") we can move the whole MPTCP rx path under the socket lock leveraging the release_cb. We can drop a bunch of spin_lock pairs in the receive functions, use a single receive queue and invoke __mptcp_move_skbs only when subflows ask for it. This will allow more cleanup in the next patch. Some changes are worth specific mention: The msk rcvbuf update now always happens under both the msk and the subflow socket lock: we can drop a bunch of ONCE annotation and consolidate the checks. When the skbs move is delayed at msk release callback time, even the msk rcvbuf update is delayed; additionally take care of such action in __mptcp_move_skbs(). Signed-off-by: Paolo Abeni --- v1 -> v2: - cleanup && fixup msk sk_rcvbuf update - fix missed wakeup due to bad placed __mptcp_move_skbs(); move it form __mptcp_recvmsg_mskq into mptcp_recvmsg() - added missing '\n' in debug message format string - keep 'snd_una' && friends update under the mptcp data lock --- net/mptcp/fastopen.c | 2 + net/mptcp/protocol.c | 123 ++++++++++++++++++++----------------------- net/mptcp/protocol.h | 2 +- 3 files changed, 61 insertions(+), 66 deletions(-) diff --git a/net/mptcp/fastopen.c b/net/mptcp/fastopen.c index a29ff901df75..fb945c0d50bf 100644 --- a/net/mptcp/fastopen.c +++ b/net/mptcp/fastopen.c @@ -49,6 +49,7 @@ void mptcp_fastopen_subflow_synack_set_params(struct mptcp_subflow_context *subf MPTCP_SKB_CB(skb)->has_rxtstamp = TCP_SKB_CB(skb)->has_rxtstamp; mptcp_data_lock(sk); + DEBUG_NET_WARN_ON_ONCE(sock_owned_by_user_nocheck(sk)); mptcp_set_owner_r(skb, sk); __skb_queue_tail(&sk->sk_receive_queue, skb); @@ -65,6 +66,7 @@ void __mptcp_fastopen_gen_msk_ackseq(struct mptcp_sock *msk, struct mptcp_subflo struct sock *sk = (struct sock *)msk; struct sk_buff *skb; + DEBUG_NET_WARN_ON_ONCE(sock_owned_by_user_nocheck(sk)); skb = skb_peek_tail(&sk->sk_receive_queue); if (skb) { WARN_ON_ONCE(MPTCP_SKB_CB(skb)->end_seq); diff --git a/net/mptcp/protocol.c b/net/mptcp/protocol.c index 690614816749..42d04de32560 100644 --- a/net/mptcp/protocol.c +++ b/net/mptcp/protocol.c @@ -643,18 +643,6 @@ static bool __mptcp_move_skbs_from_subflow(struct mptcp_sock *msk, bool more_data_avail; struct tcp_sock *tp; bool done = false; - int sk_rbuf; - - sk_rbuf = READ_ONCE(sk->sk_rcvbuf); - - if (!(sk->sk_userlocks & SOCK_RCVBUF_LOCK)) { - int ssk_rbuf = READ_ONCE(ssk->sk_rcvbuf); - - if (unlikely(ssk_rbuf > sk_rbuf)) { - WRITE_ONCE(sk->sk_rcvbuf, ssk_rbuf); - sk_rbuf = ssk_rbuf; - } - } pr_debug("msk=%p ssk=%p\n", msk, ssk); tp = tcp_sk(ssk); @@ -722,7 +710,7 @@ static bool __mptcp_move_skbs_from_subflow(struct mptcp_sock *msk, WRITE_ONCE(tp->copied_seq, seq); more_data_avail = mptcp_subflow_data_available(ssk); - if (atomic_read(&sk->sk_rmem_alloc) > sk_rbuf) { + if (atomic_read(&sk->sk_rmem_alloc) > sk->sk_rcvbuf) { done = true; break; } @@ -846,11 +834,30 @@ static bool move_skbs_to_msk(struct mptcp_sock *msk, struct sock *ssk) return moved > 0; } +static void __mptcp_rcvbuf_update(struct sock *sk, struct sock *ssk) +{ + if (unlikely(ssk->sk_rcvbuf > sk->sk_rcvbuf)) + WRITE_ONCE(sk->sk_rcvbuf, ssk->sk_rcvbuf); +} + +static void __mptcp_data_ready(struct sock *sk, struct sock *ssk) +{ + struct mptcp_sock *msk = mptcp_sk(sk); + + __mptcp_rcvbuf_update(sk, ssk); + + /* over limit? can't append more skbs to msk, Also, no need to wake-up*/ + if (__mptcp_rmem(sk) > sk->sk_rcvbuf) + return; + + /* Wake-up the reader only for in-sequence data */ + if (move_skbs_to_msk(msk, ssk) && mptcp_epollin_ready(sk)) + sk->sk_data_ready(sk); +} + void mptcp_data_ready(struct sock *sk, struct sock *ssk) { struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(ssk); - struct mptcp_sock *msk = mptcp_sk(sk); - int sk_rbuf, ssk_rbuf; /* The peer can send data while we are shutting down this * subflow at msk destruction time, but we must avoid enqueuing @@ -859,19 +866,11 @@ void mptcp_data_ready(struct sock *sk, struct sock *ssk) if (unlikely(subflow->disposable)) return; - ssk_rbuf = READ_ONCE(ssk->sk_rcvbuf); - sk_rbuf = READ_ONCE(sk->sk_rcvbuf); - if (unlikely(ssk_rbuf > sk_rbuf)) - sk_rbuf = ssk_rbuf; - - /* over limit? can't append more skbs to msk, Also, no need to wake-up*/ - if (__mptcp_rmem(sk) > sk_rbuf) - return; - - /* Wake-up the reader only for in-sequence data */ mptcp_data_lock(sk); - if (move_skbs_to_msk(msk, ssk) && mptcp_epollin_ready(sk)) - sk->sk_data_ready(sk); + if (!sock_owned_by_user(sk)) + __mptcp_data_ready(sk, ssk); + else + __set_bit(MPTCP_DEQUEUE, &mptcp_sk(sk)->cb_flags); mptcp_data_unlock(sk); } @@ -1942,16 +1941,17 @@ static int mptcp_sendmsg(struct sock *sk, struct msghdr *msg, size_t len) static void mptcp_rcv_space_adjust(struct mptcp_sock *msk, int copied); -static int __mptcp_recvmsg_mskq(struct mptcp_sock *msk, +static int __mptcp_recvmsg_mskq(struct sock *sk, struct msghdr *msg, size_t len, int flags, struct scm_timestamping_internal *tss, int *cmsg_flags) { + struct mptcp_sock *msk = mptcp_sk(sk); struct sk_buff *skb, *tmp; int copied = 0; - skb_queue_walk_safe(&msk->receive_queue, skb, tmp) { + skb_queue_walk_safe(&sk->sk_receive_queue, skb, tmp) { u32 offset = MPTCP_SKB_CB(skb)->offset; u32 data_len = skb->len - offset; u32 count = min_t(size_t, len - copied, data_len); @@ -1986,7 +1986,7 @@ static int __mptcp_recvmsg_mskq(struct mptcp_sock *msk, /* we will bulk release the skb memory later */ skb->destructor = NULL; WRITE_ONCE(msk->rmem_released, msk->rmem_released + skb->truesize); - __skb_unlink(skb, &msk->receive_queue); + __skb_unlink(skb, &sk->sk_receive_queue); __kfree_skb(skb); msk->bytes_consumed += count; } @@ -2111,54 +2111,46 @@ static void __mptcp_update_rmem(struct sock *sk) WRITE_ONCE(msk->rmem_released, 0); } -static void __mptcp_splice_receive_queue(struct sock *sk) +static bool __mptcp_move_skbs(struct sock *sk) { + struct mptcp_subflow_context *subflow; struct mptcp_sock *msk = mptcp_sk(sk); - - skb_queue_splice_tail_init(&sk->sk_receive_queue, &msk->receive_queue); -} - -static bool __mptcp_move_skbs(struct mptcp_sock *msk) -{ - struct sock *sk = (struct sock *)msk; unsigned int moved = 0; bool ret, done; + /* verify we can move any data from the subflow, eventually updating */ + if (!(sk->sk_userlocks & SOCK_RCVBUF_LOCK)) + mptcp_for_each_subflow(msk, subflow) + __mptcp_rcvbuf_update(sk, subflow->tcp_sock); + + if (__mptcp_rmem(sk) > sk->sk_rcvbuf) + return false; + do { struct sock *ssk = mptcp_subflow_recv_lookup(msk); bool slowpath; - /* we can have data pending in the subflows only if the msk - * receive buffer was full at subflow_data_ready() time, - * that is an unlikely slow path. - */ - if (likely(!ssk)) + if (unlikely(!ssk)) break; slowpath = lock_sock_fast(ssk); - mptcp_data_lock(sk); __mptcp_update_rmem(sk); done = __mptcp_move_skbs_from_subflow(msk, ssk, &moved); - mptcp_data_unlock(sk); if (unlikely(ssk->sk_err)) __mptcp_error_report(sk); unlock_sock_fast(ssk, slowpath); } while (!done); - /* acquire the data lock only if some input data is pending */ ret = moved > 0; if (!RB_EMPTY_ROOT(&msk->out_of_order_queue) || - !skb_queue_empty_lockless(&sk->sk_receive_queue)) { - mptcp_data_lock(sk); + !skb_queue_empty(&sk->sk_receive_queue)) { __mptcp_update_rmem(sk); ret |= __mptcp_ofo_queue(msk); - __mptcp_splice_receive_queue(sk); - mptcp_data_unlock(sk); } if (ret) mptcp_check_data_fin((struct sock *)msk); - return !skb_queue_empty(&msk->receive_queue); + return ret; } static unsigned int mptcp_inq_hint(const struct sock *sk) @@ -2166,7 +2158,7 @@ static unsigned int mptcp_inq_hint(const struct sock *sk) const struct mptcp_sock *msk = mptcp_sk(sk); const struct sk_buff *skb; - skb = skb_peek(&msk->receive_queue); + skb = skb_peek(&sk->sk_receive_queue); if (skb) { u64 hint_val = READ_ONCE(msk->ack_seq) - MPTCP_SKB_CB(skb)->map_seq; @@ -2212,7 +2204,7 @@ static int mptcp_recvmsg(struct sock *sk, struct msghdr *msg, size_t len, while (copied < len) { int err, bytes_read; - bytes_read = __mptcp_recvmsg_mskq(msk, msg, len - copied, flags, &tss, &cmsg_flags); + bytes_read = __mptcp_recvmsg_mskq(sk, msg, len - copied, flags, &tss, &cmsg_flags); if (unlikely(bytes_read < 0)) { if (!copied) copied = bytes_read; @@ -2221,7 +2213,7 @@ static int mptcp_recvmsg(struct sock *sk, struct msghdr *msg, size_t len, copied += bytes_read; - if (skb_queue_empty(&msk->receive_queue) && __mptcp_move_skbs(msk)) + if (skb_queue_empty(&sk->sk_receive_queue) && __mptcp_move_skbs(sk)) continue; /* only the MPTCP socket status is relevant here. The exit @@ -2247,7 +2239,7 @@ static int mptcp_recvmsg(struct sock *sk, struct msghdr *msg, size_t len, /* race breaker: the shutdown could be after the * previous receive queue check */ - if (__mptcp_move_skbs(msk)) + if (__mptcp_move_skbs(sk)) continue; break; } @@ -2291,9 +2283,8 @@ static int mptcp_recvmsg(struct sock *sk, struct msghdr *msg, size_t len, } } - pr_debug("msk=%p rx queue empty=%d:%d copied=%d\n", - msk, skb_queue_empty_lockless(&sk->sk_receive_queue), - skb_queue_empty(&msk->receive_queue), copied); + pr_debug("msk=%p rx queue empty=%d copied=%d\n", + msk, skb_queue_empty(&sk->sk_receive_queue), copied); release_sock(sk); return copied; @@ -2820,7 +2811,6 @@ static void __mptcp_init_sock(struct sock *sk) INIT_LIST_HEAD(&msk->join_list); INIT_LIST_HEAD(&msk->rtx_queue); INIT_WORK(&msk->work, mptcp_worker); - __skb_queue_head_init(&msk->receive_queue); msk->out_of_order_queue = RB_ROOT; msk->first_pending = NULL; WRITE_ONCE(msk->rmem_fwd_alloc, 0); @@ -3403,12 +3393,8 @@ void mptcp_destroy_common(struct mptcp_sock *msk, unsigned int flags) mptcp_for_each_subflow_safe(msk, subflow, tmp) __mptcp_close_ssk(sk, mptcp_subflow_tcp_sock(subflow), subflow, flags); - /* move to sk_receive_queue, sk_stream_kill_queues will purge it */ - mptcp_data_lock(sk); - skb_queue_splice_tail_init(&msk->receive_queue, &sk->sk_receive_queue); __skb_queue_purge(&sk->sk_receive_queue); skb_rbtree_purge(&msk->out_of_order_queue); - mptcp_data_unlock(sk); /* move all the rx fwd alloc into the sk_mem_reclaim_final in * inet_sock_destruct() will dispose it @@ -3451,7 +3437,8 @@ void __mptcp_check_push(struct sock *sk, struct sock *ssk) #define MPTCP_FLAGS_PROCESS_CTX_NEED (BIT(MPTCP_PUSH_PENDING) | \ BIT(MPTCP_RETRANSMIT) | \ - BIT(MPTCP_FLUSH_JOIN_LIST)) + BIT(MPTCP_FLUSH_JOIN_LIST) | \ + BIT(MPTCP_DEQUEUE)) /* processes deferred events and flush wmem */ static void mptcp_release_cb(struct sock *sk) @@ -3485,6 +3472,11 @@ static void mptcp_release_cb(struct sock *sk) __mptcp_push_pending(sk, 0); if (flags & BIT(MPTCP_RETRANSMIT)) __mptcp_retrans(sk); + if ((flags & BIT(MPTCP_DEQUEUE)) && __mptcp_move_skbs(sk)) { + /* notify ack seq update */ + mptcp_cleanup_rbuf(msk, 0); + sk->sk_data_ready(sk); + } cond_resched(); spin_lock_bh(&sk->sk_lock.slock); @@ -3722,7 +3714,8 @@ static int mptcp_ioctl(struct sock *sk, int cmd, int *karg) return -EINVAL; lock_sock(sk); - __mptcp_move_skbs(msk); + if (__mptcp_move_skbs(sk)) + mptcp_cleanup_rbuf(msk, 0); *karg = mptcp_inq_hint(sk); release_sock(sk); break; diff --git a/net/mptcp/protocol.h b/net/mptcp/protocol.h index b4c72a73594f..ad940cc1f26f 100644 --- a/net/mptcp/protocol.h +++ b/net/mptcp/protocol.h @@ -124,6 +124,7 @@ #define MPTCP_FLUSH_JOIN_LIST 5 #define MPTCP_SYNC_STATE 6 #define MPTCP_SYNC_SNDBUF 7 +#define MPTCP_DEQUEUE 8 struct mptcp_skb_cb { u64 map_seq; @@ -322,7 +323,6 @@ struct mptcp_sock { struct work_struct work; struct sk_buff *ooo_last_skb; struct rb_root out_of_order_queue; - struct sk_buff_head receive_queue; struct list_head conn_list; struct list_head rtx_queue; struct mptcp_data_frag *first_pending;