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=-2.8 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_PASS,T_DKIMWL_WL_MED, URIBL_BLOCKED,USER_AGENT_GIT 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 761FDECDFBB for ; Wed, 18 Jul 2018 22:59:18 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 215722075E for ; Wed, 18 Jul 2018 22:59:18 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=osandov-com.20150623.gappssmtp.com header.i=@osandov-com.20150623.gappssmtp.com header.b="cF0Z4Cx3" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 215722075E Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=osandov.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730220AbeGRXjW (ORCPT ); Wed, 18 Jul 2018 19:39:22 -0400 Received: from mail-pl0-f67.google.com ([209.85.160.67]:41010 "EHLO mail-pl0-f67.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729914AbeGRXjV (ORCPT ); Wed, 18 Jul 2018 19:39:21 -0400 Received: by mail-pl0-f67.google.com with SMTP id w8-v6so2684278ply.8 for ; Wed, 18 Jul 2018 15:59:15 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=osandov-com.20150623.gappssmtp.com; s=20150623; h=from:to:cc:subject:date:message-id:in-reply-to:references; bh=OwRfXeF6NHIzrPioZ/8+JLBpzHWc2t/vrZ/aQ57UqDg=; b=cF0Z4Cx3o1pCQgXtmovhU7GvX2yWA2470gy8ygcUifBPiMV49ps2S/3XwQK36MEvJW ioSwSl3mwSHd1s99wPwODReKgJ54EoLrbOteUKA8jmtFgkuwJofr+syvG2TtNYc7nLO9 OVl0lzHIrOnwn6vikXOl3cUhAPSuVBLyL0OeKCRCH+6FKZMFWeZTWxDZO2iLufo7VKSL NkqEc16S6JR4Oa+0hQLoqq2zFjrvY47J0aH+DQvx0AMhkbp6j9j82wnsOcl+9TtazkjV xjSElo5ezFmZdJBgGNqKvQhCigNa6KuN7zYtCEHxNZkgIIGb2GU9vqmc2sDFSUYd8diF e+pw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references; bh=OwRfXeF6NHIzrPioZ/8+JLBpzHWc2t/vrZ/aQ57UqDg=; b=gxotVikXdl+MmIvW/DOt1gUiuZ0ER2km/RcVBpMflFx9mW8GMp6OwNuLRFt/6okFHD peMWmERcvssi7ITJon3URYyq1iV9nmVAWywiOwSN23YF5AJ5zO8hfZzUqYuTHpdF4m+6 MTD5wE0J7kXszWoGqr1gu7moTkWOchSGN8kxZA0hcFx6LL0nNK83DxjWhit0kk3OXl40 P4pGUa1kCcu8K5k26Q6FuST6ezOzqBYal7E24kMTuaO0oaDpqErAj0RI1vi6lMyApv7/ oS8fVxC0PNKbwgC7P+TBdPSyC2ROdyfI4Xqp4WSgYzUdrDMzxhCeuOYP98aot69Uf3m1 4tNg== X-Gm-Message-State: AOUpUlE/vLVkY5KM3CvAreGp5RXiMmDbL3ZCH7/o93cvizaXRR79pdLx 2LK1gnY3ZJSMDh9rQdV5bk4ppaL3E48= X-Google-Smtp-Source: AAOMgpeYVGw86XzdZa5L442PRAu081YO9Wzf6lGPvdlkVE2ffqFRj1adxaKZWsCr4wMe1FO4P+jjVg== X-Received: by 2002:a17:902:262:: with SMTP id 89-v6mr7643504plc.221.1531954754505; Wed, 18 Jul 2018 15:59:14 -0700 (PDT) Received: from vader.hsd1.wa.comcast.net ([2601:602:8800:a9a9:e6a7:a0ff:fe0b:c9a8]) by smtp.gmail.com with ESMTPSA id s16-v6sm6377946pfm.114.2018.07.18.15.59.13 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Wed, 18 Jul 2018 15:59:14 -0700 (PDT) From: Omar Sandoval To: linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org, Andrew Morton Cc: Alexey Dobriyan , Eric Biederman , James Morse , Bhupesh Sharma , kernel-team@fb.com Subject: [PATCH v3 1/8] proc/kcore: don't grab lock for kclist_add() Date: Wed, 18 Jul 2018 15:58:41 -0700 Message-Id: <98208db1faf167aa8b08eebfa968d95c70527739.1531953780.git.osandov@fb.com> X-Mailer: git-send-email 2.18.0 In-Reply-To: References: Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Omar Sandoval kclist_add() is only called at init time, so there's no point in grabbing any locks. We're also going to replace the rwlock with a rwsem, which we don't want to try grabbing during early boot. While we're here, mark kclist_add() with __init so that we'll get a warning if it's called from non-init code. Signed-off-by: Omar Sandoval --- fs/proc/kcore.c | 7 +++---- include/linux/kcore.h | 2 +- 2 files changed, 4 insertions(+), 5 deletions(-) diff --git a/fs/proc/kcore.c b/fs/proc/kcore.c index 66c373230e60..b0b9a76f28d6 100644 --- a/fs/proc/kcore.c +++ b/fs/proc/kcore.c @@ -62,16 +62,15 @@ static LIST_HEAD(kclist_head); static DEFINE_RWLOCK(kclist_lock); static int kcore_need_update = 1; -void -kclist_add(struct kcore_list *new, void *addr, size_t size, int type) +/* This doesn't grab kclist_lock, so it should only be used at init time. */ +void __init kclist_add(struct kcore_list *new, void *addr, size_t size, + int type) { new->addr = (unsigned long)addr; new->size = size; new->type = type; - write_lock(&kclist_lock); list_add_tail(&new->list, &kclist_head); - write_unlock(&kclist_lock); } static size_t get_kcore_size(int *nphdr, size_t *elf_buflen) diff --git a/include/linux/kcore.h b/include/linux/kcore.h index 8de55e4b5ee9..c20f296438fb 100644 --- a/include/linux/kcore.h +++ b/include/linux/kcore.h @@ -35,7 +35,7 @@ struct vmcoredd_node { }; #ifdef CONFIG_PROC_KCORE -extern void kclist_add(struct kcore_list *, void *, size_t, int type); +void __init kclist_add(struct kcore_list *, void *, size_t, int type); #else static inline void kclist_add(struct kcore_list *new, void *addr, size_t size, int type) -- 2.18.0