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=-9.0 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_PASS,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 20EABC04AB4 for ; Thu, 9 May 2019 18:10:24 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id E61232084E for ; Thu, 9 May 2019 18:10:23 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=alien8.de header.i=@alien8.de header.b="Emld8reu" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726809AbfEISJg (ORCPT ); Thu, 9 May 2019 14:09:36 -0400 Received: from mail.skyhub.de ([5.9.137.197]:36964 "EHLO mail.skyhub.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726775AbfEISJe (ORCPT ); Thu, 9 May 2019 14:09:34 -0400 Received: from zn.tnic (p200300EC2F0F5F0071783F241746291C.dip0.t-ipconnect.de [IPv6:2003:ec:2f0f:5f00:7178:3f24:1746:291c]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.skyhub.de (SuperMail on ZX Spectrum 128k) with ESMTPSA id 103FC1EC0B5A; Thu, 9 May 2019 20:09:33 +0200 (CEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=alien8.de; s=dkim; t=1557425373; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=UEXWg2URSKnWXuSJJUpT1EWR6AmDhcNd64KRaHH2jHw=; b=Emld8reuLmtKbRjyo9ql6Sr9lWXJv1runSwtI4sDUDYwgUEniLpUEgI1zE0gZsx3byYjee SlZvFhHxcWZ3azxMbaDViLO2XhvXTYOoOEDeHKMKl/7zHyJ4TOrYmgPvUAudhHmJNLlxsG C7o8ASnoaYhxg9+c55SeSYacmOgyoMU= From: Borislav Petkov To: Tony Luck Cc: linux-edac , LKML Subject: [PATCH 02/11] RAS/CEC: Convert the timer callback to a workqueue Date: Thu, 9 May 2019 20:09:17 +0200 Message-Id: <20190509180926.31932-3-bp@alien8.de> X-Mailer: git-send-email 2.21.0 In-Reply-To: <20190509180926.31932-1-bp@alien8.de> References: <20190509180926.31932-1-bp@alien8.de> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Cong Wang cec_timer_fn() is a timer callback which reads ce_arr.array[] and updates its decay values. However, it runs in interrupt context and the mutex protection the CEC uses for that array, is inadequate. Convert the used timer to a workqueue to keep the tasks the CEC performs preemptible and thus low-prio. [ bp: Rewrite commit message. s/timer/decay/gi to make it agnostic as to what facility is used. ] Fixes: 011d82611172 ("RAS: Add a Corrected Errors Collector") Signed-off-by: Cong Wang Signed-off-by: Borislav Petkov Cc: Thomas Gleixner Cc: Tony Luck Cc: linux-edac Cc: Link: https://lkml.kernel.org/r/20190416213351.28999-2-xiyou.wangcong@gmail.com --- drivers/ras/cec.c | 46 ++++++++++++++++++++++------------------------ 1 file changed, 22 insertions(+), 24 deletions(-) diff --git a/drivers/ras/cec.c b/drivers/ras/cec.c index dbfe3e61d2c2..673f8a128397 100644 --- a/drivers/ras/cec.c +++ b/drivers/ras/cec.c @@ -2,6 +2,7 @@ #include #include #include +#include #include @@ -123,16 +124,12 @@ static u64 dfs_pfn; /* Amount of errors after which we offline */ static unsigned int count_threshold = COUNT_MASK; -/* - * The timer "decays" element count each timer_interval which is 24hrs by - * default. - */ - -#define CEC_TIMER_DEFAULT_INTERVAL 24 * 60 * 60 /* 24 hrs */ -#define CEC_TIMER_MIN_INTERVAL 1 * 60 * 60 /* 1h */ -#define CEC_TIMER_MAX_INTERVAL 30 * 24 * 60 * 60 /* one month */ -static struct timer_list cec_timer; -static u64 timer_interval = CEC_TIMER_DEFAULT_INTERVAL; +/* Each element "decays" each decay_interval which is 24hrs by default. */ +#define CEC_DECAY_DEFAULT_INTERVAL 24 * 60 * 60 /* 24 hrs */ +#define CEC_DECAY_MIN_INTERVAL 1 * 60 * 60 /* 1h */ +#define CEC_DECAY_MAX_INTERVAL 30 * 24 * 60 * 60 /* one month */ +static struct delayed_work cec_work; +static u64 decay_interval = CEC_DECAY_DEFAULT_INTERVAL; /* * Decrement decay value. We're using DECAY_BITS bits to denote decay of an @@ -160,20 +157,21 @@ static void do_spring_cleaning(struct ce_array *ca) /* * @interval in seconds */ -static void cec_mod_timer(struct timer_list *t, unsigned long interval) +static void cec_mod_work(unsigned long interval) { unsigned long iv; - iv = interval * HZ + jiffies; - - mod_timer(t, round_jiffies(iv)); + iv = interval * HZ; + mod_delayed_work(system_wq, &cec_work, round_jiffies(iv)); } -static void cec_timer_fn(struct timer_list *unused) +static void cec_work_fn(struct work_struct *work) { + mutex_lock(&ce_mutex); do_spring_cleaning(&ce_arr); + mutex_unlock(&ce_mutex); - cec_mod_timer(&cec_timer, timer_interval); + cec_mod_work(decay_interval); } /* @@ -380,15 +378,15 @@ static int decay_interval_set(void *data, u64 val) { *(u64 *)data = val; - if (val < CEC_TIMER_MIN_INTERVAL) + if (val < CEC_DECAY_MIN_INTERVAL) return -EINVAL; - if (val > CEC_TIMER_MAX_INTERVAL) + if (val > CEC_DECAY_MAX_INTERVAL) return -EINVAL; - timer_interval = val; + decay_interval = val; - cec_mod_timer(&cec_timer, timer_interval); + cec_mod_work(decay_interval); return 0; } DEFINE_DEBUGFS_ATTRIBUTE(decay_interval_ops, u64_get, decay_interval_set, "%lld\n"); @@ -432,7 +430,7 @@ static int array_dump(struct seq_file *m, void *v) seq_printf(m, "Flags: 0x%x\n", ca->flags); - seq_printf(m, "Timer interval: %lld seconds\n", timer_interval); + seq_printf(m, "Decay interval: %lld seconds\n", decay_interval); seq_printf(m, "Decays: %lld\n", ca->decays_done); seq_printf(m, "Action threshold: %d\n", count_threshold); @@ -478,7 +476,7 @@ static int __init create_debugfs_nodes(void) } decay = debugfs_create_file("decay_interval", S_IRUSR | S_IWUSR, d, - &timer_interval, &decay_interval_ops); + &decay_interval, &decay_interval_ops); if (!decay) { pr_warn("Error creating decay_interval debugfs node!\n"); goto err; @@ -514,8 +512,8 @@ void __init cec_init(void) if (create_debugfs_nodes()) return; - timer_setup(&cec_timer, cec_timer_fn, 0); - cec_mod_timer(&cec_timer, CEC_TIMER_DEFAULT_INTERVAL); + INIT_DELAYED_WORK(&cec_work, cec_work_fn); + schedule_delayed_work(&cec_work, CEC_DECAY_DEFAULT_INTERVAL); pr_info("Correctable Errors collector initialized.\n"); } -- 2.21.0