From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-10.1 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 67F92C432C3 for ; Sat, 16 Nov 2019 16:24:00 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 413F2214DE for ; Sat, 16 Nov 2019 16:24:00 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1573921440; bh=Dj2rTLwWDO1pOTVTST4jx2q+awzIqfqNPlMUZC3OWqM=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=OgbjjwCfuLi4ze8q313AfZJ4Xdmki0i2kKYyJCN1i7QxfTB0FLIitbMs452+pcBhZ tnudXNEAsdjT/g8ARHNSLKGWxtjPPa3Dvsv7lydsqYfEkme6wXha2NEozAm1q3qRat b0x5DiG8jt6W/+A5aCoxNvyELbyjeqonI1O5YJ84= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728431AbfKPPmp (ORCPT ); Sat, 16 Nov 2019 10:42:45 -0500 Received: from mail.kernel.org ([198.145.29.99]:46518 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728408AbfKPPmo (ORCPT ); Sat, 16 Nov 2019 10:42:44 -0500 Received: from sasha-vm.mshome.net (unknown [50.234.116.4]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 11D9C2084E; Sat, 16 Nov 2019 15:42:43 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1573918963; bh=Dj2rTLwWDO1pOTVTST4jx2q+awzIqfqNPlMUZC3OWqM=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=YWSwGJDYb0S1qe158zQ5AN5ZFUc5s+vMe4qlzglMtPiQfXg7OmMf6hfWTPINHx/gY FkIBKZAPOxqz7ziL1MEON0X3SPKXO4RcGoqPHsdX+RIITzSg6V0Qfyo7xGFCuREECu eYFgCC5a+GprUrPgxSCt5x5gJXZASEnge1V2EW/g= From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Xin Long , "David S . Miller" , Sasha Levin , linux-sctp@vger.kernel.org, netdev@vger.kernel.org Subject: [PATCH AUTOSEL 4.19 079/237] sctp: use sk_wmem_queued to check for writable space Date: Sat, 16 Nov 2019 10:38:34 -0500 Message-Id: <20191116154113.7417-79-sashal@kernel.org> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20191116154113.7417-1-sashal@kernel.org> References: <20191116154113.7417-1-sashal@kernel.org> MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org From: Xin Long [ Upstream commit cd305c74b0f8b49748a79a8f67fc8e5e3e0c4794 ] sk->sk_wmem_queued is used to count the size of chunks in out queue while sk->sk_wmem_alloc is for counting the size of chunks has been sent. sctp is increasing both of them before enqueuing the chunks, and using sk->sk_wmem_alloc to check for writable space. However, sk_wmem_alloc is also increased by 1 for the skb allocked for sending in sctp_packet_transmit() but it will not wake up the waiters when sk_wmem_alloc is decreased in this skb's destructor. If msg size is equal to sk_sndbuf and sendmsg is waiting for sndbuf, the check 'msg_len <= sctp_wspace(asoc)' in sctp_wait_for_sndbuf() will keep waiting if there's a skb allocked in sctp_packet_transmit, and later even if this skb got freed, the waiting thread will never get waked up. This issue has been there since very beginning, so we change to use sk->sk_wmem_queued to check for writable space as sk_wmem_queued is not increased for the skb allocked for sending, also as TCP does. SOCK_SNDBUF_LOCK check is also removed here as it's for tx buf auto tuning which I will add in another patch. Signed-off-by: Xin Long Signed-off-by: David S. Miller Signed-off-by: Sasha Levin --- net/sctp/socket.c | 38 +++++++++----------------------------- 1 file changed, 9 insertions(+), 29 deletions(-) diff --git a/net/sctp/socket.c b/net/sctp/socket.c index c766315527226..e7a11cd7633f5 100644 --- a/net/sctp/socket.c +++ b/net/sctp/socket.c @@ -83,7 +83,7 @@ #include /* Forward declarations for internal helper functions. */ -static int sctp_writeable(struct sock *sk); +static bool sctp_writeable(struct sock *sk); static void sctp_wfree(struct sk_buff *skb); static int sctp_wait_for_sndbuf(struct sctp_association *asoc, long *timeo_p, size_t msg_len); @@ -119,25 +119,10 @@ static void sctp_enter_memory_pressure(struct sock *sk) /* Get the sndbuf space available at the time on the association. */ static inline int sctp_wspace(struct sctp_association *asoc) { - int amt; + struct sock *sk = asoc->base.sk; - if (asoc->ep->sndbuf_policy) - amt = asoc->sndbuf_used; - else - amt = sk_wmem_alloc_get(asoc->base.sk); - - if (amt >= asoc->base.sk->sk_sndbuf) { - if (asoc->base.sk->sk_userlocks & SOCK_SNDBUF_LOCK) - amt = 0; - else { - amt = sk_stream_wspace(asoc->base.sk); - if (amt < 0) - amt = 0; - } - } else { - amt = asoc->base.sk->sk_sndbuf - amt; - } - return amt; + return asoc->ep->sndbuf_policy ? sk->sk_sndbuf - asoc->sndbuf_used + : sk_stream_wspace(sk); } /* Increment the used sndbuf space count of the corresponding association by @@ -1928,10 +1913,10 @@ static int sctp_sendmsg_to_asoc(struct sctp_association *asoc, asoc->pmtu_pending = 0; } - if (sctp_wspace(asoc) < msg_len) + if (sctp_wspace(asoc) < (int)msg_len) sctp_prsctp_prune(asoc, sinfo, msg_len - sctp_wspace(asoc)); - if (!sctp_wspace(asoc)) { + if (sctp_wspace(asoc) <= 0) { timeo = sock_sndtimeo(sk, msg->msg_flags & MSG_DONTWAIT); err = sctp_wait_for_sndbuf(asoc, &timeo, msg_len); if (err) @@ -8516,7 +8501,7 @@ static int sctp_wait_for_sndbuf(struct sctp_association *asoc, long *timeo_p, goto do_error; if (signal_pending(current)) goto do_interrupted; - if (msg_len <= sctp_wspace(asoc)) + if ((int)msg_len <= sctp_wspace(asoc)) break; /* Let another process have a go. Since we are going @@ -8591,14 +8576,9 @@ void sctp_write_space(struct sock *sk) * UDP-style sockets or TCP-style sockets, this code should work. * - Daisy */ -static int sctp_writeable(struct sock *sk) +static bool sctp_writeable(struct sock *sk) { - int amt = 0; - - amt = sk->sk_sndbuf - sk_wmem_alloc_get(sk); - if (amt < 0) - amt = 0; - return amt; + return sk->sk_sndbuf > sk->sk_wmem_queued; } /* Wait for an association to go into ESTABLISHED state. If timeout is 0, -- 2.20.1