From patchwork Fri Apr 16 15:11:46 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Sabrina Dubroca X-Patchwork-Id: 12207977 X-Patchwork-Delegate: kuba@kernel.org 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=-13.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=ham 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 9F410C433ED for ; Fri, 16 Apr 2021 15:15:38 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 6D08961166 for ; Fri, 16 Apr 2021 15:15:38 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S245504AbhDPPN7 convert rfc822-to-8bit (ORCPT ); Fri, 16 Apr 2021 11:13:59 -0400 Received: from us-smtp-delivery-44.mimecast.com ([207.211.30.44]:26386 "EHLO us-smtp-delivery-44.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S244955AbhDPPN0 (ORCPT ); Fri, 16 Apr 2021 11:13:26 -0400 Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-137-aMx0w6q8NOSY-8kv_mW_dQ-1; Fri, 16 Apr 2021 11:11:52 -0400 X-MC-Unique: aMx0w6q8NOSY-8kv_mW_dQ-1 Received: from smtp.corp.redhat.com (int-mx08.intmail.prod.int.phx2.redhat.com [10.5.11.23]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id AD06C85EE8B; Fri, 16 Apr 2021 15:11:50 +0000 (UTC) Received: from hog.localdomain (unknown [10.40.192.89]) by smtp.corp.redhat.com (Postfix) with ESMTP id CFECE196E3; Fri, 16 Apr 2021 15:11:48 +0000 (UTC) From: Sabrina Dubroca To: netdev@vger.kernel.org Cc: steffen.klassert@secunet.com, Sabrina Dubroca , Juri Lelli , Xiumei Mu , Sebastian Andrzej Siewior Subject: [PATCH ipsec-next] xfrm: ipcomp: remove unnecessary get_cpu() Date: Fri, 16 Apr 2021 17:11:46 +0200 Message-Id: <2bc5f05b0c50082cf0f5c817ae7c9f660848f146.1618394396.git.sd@queasysnail.net> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.84 on 10.5.11.23 X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: queasysnail.net Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org X-Patchwork-Delegate: kuba@kernel.org While testing ipcomp on a realtime kernel, Xiumei reported a "sleeping in atomic" bug, caused by a memory allocation while preemption is disabled (ipcomp_decompress -> alloc_page -> ... get_page_from_freelist). As Sebastian noted [1], this get_cpu() isn't actually needed, since ipcomp_decompress() is called in napi context anyway, so BH is already disabled. This patch replaces get_cpu + per_cpu_ptr with this_cpu_ptr, then simplifies the error returns, since there isn't any common operation left. [1] https://lore.kernel.org/lkml/20190820082810.ixkmi56fp7u7eyn2@linutronix.de/ Cc: Juri Lelli Reported-by: Xiumei Mu Suggested-by: Sebastian Andrzej Siewior Signed-off-by: Sabrina Dubroca --- net/xfrm/xfrm_ipcomp.c | 25 ++++++++----------------- 1 file changed, 8 insertions(+), 17 deletions(-) diff --git a/net/xfrm/xfrm_ipcomp.c b/net/xfrm/xfrm_ipcomp.c index 4d422447aadc..2e8afe078d61 100644 --- a/net/xfrm/xfrm_ipcomp.c +++ b/net/xfrm/xfrm_ipcomp.c @@ -41,19 +41,16 @@ static int ipcomp_decompress(struct xfrm_state *x, struct sk_buff *skb) const int plen = skb->len; int dlen = IPCOMP_SCRATCH_SIZE; const u8 *start = skb->data; - const int cpu = get_cpu(); - u8 *scratch = *per_cpu_ptr(ipcomp_scratches, cpu); - struct crypto_comp *tfm = *per_cpu_ptr(ipcd->tfms, cpu); + u8 *scratch = *this_cpu_ptr(ipcomp_scratches); + struct crypto_comp *tfm = *this_cpu_ptr(ipcd->tfms); int err = crypto_comp_decompress(tfm, start, plen, scratch, &dlen); int len; if (err) - goto out; + return err; - if (dlen < (plen + sizeof(struct ip_comp_hdr))) { - err = -EINVAL; - goto out; - } + if (dlen < (plen + sizeof(struct ip_comp_hdr))) + return -EINVAL; len = dlen - plen; if (len > skb_tailroom(skb)) @@ -68,16 +65,14 @@ static int ipcomp_decompress(struct xfrm_state *x, struct sk_buff *skb) skb_frag_t *frag; struct page *page; - err = -EMSGSIZE; if (WARN_ON(skb_shinfo(skb)->nr_frags >= MAX_SKB_FRAGS)) - goto out; + return -EMSGSIZE; frag = skb_shinfo(skb)->frags + skb_shinfo(skb)->nr_frags; page = alloc_page(GFP_ATOMIC); - err = -ENOMEM; if (!page) - goto out; + return -ENOMEM; __skb_frag_set_page(frag, page); @@ -96,11 +91,7 @@ static int ipcomp_decompress(struct xfrm_state *x, struct sk_buff *skb) skb_shinfo(skb)->nr_frags++; } - err = 0; - -out: - put_cpu(); - return err; + return 0; } int ipcomp_input(struct xfrm_state *x, struct sk_buff *skb)