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=-6.8 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED 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 6546CC352A2 for ; Fri, 7 Feb 2020 08:46:43 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 39B94214AF for ; Fri, 7 Feb 2020 08:46:43 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1581065203; bh=MljgxvPdWh/SrkfvkMTa+CfcBRakaIAv5N/ZV5TYOF8=; h=Subject:To:Cc:From:Date:List-ID:From; b=NH9lv+NTPDP+oUsw5NjhscP1ReCmzPgXBZamYZ5iTBvaY1QTjyO7McQoy5U5NiBy6 vK9/CD7XSfcl6AyJ7Vk1wN69M4v6bBLAFMxcv/Ta3Z/e/GFWpAg1rVXjXJhFgNpRav WrwTqCq7YhHwVBmFmze4q/tk2ciHYbFNrnjWvWRk= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726573AbgBGIqm (ORCPT ); Fri, 7 Feb 2020 03:46:42 -0500 Received: from out2-smtp.messagingengine.com ([66.111.4.26]:58691 "EHLO out2-smtp.messagingengine.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726451AbgBGIqm (ORCPT ); Fri, 7 Feb 2020 03:46:42 -0500 Received: from compute6.internal (compute6.nyi.internal [10.202.2.46]) by mailout.nyi.internal (Postfix) with ESMTP id BF73E21E97; Fri, 7 Feb 2020 03:46:41 -0500 (EST) Received: from mailfrontend2 ([10.202.2.163]) by compute6.internal (MEProxy); Fri, 07 Feb 2020 03:46:41 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d= messagingengine.com; h=cc:content-transfer-encoding:content-type :date:from:message-id:mime-version:subject:to:x-me-proxy :x-me-proxy:x-me-sender:x-me-sender:x-sasl-enc; s=fm2; bh=RGM9am QV19wcKHmcSbcwR2Dd7KRKvaUUsiKhFirwoeA=; b=bDlVKEluJil9xTE+ShR0yJ JEeWulgkvXRL/lDQMJf3weEuABaYnsba7HjaxarGeDVxwyzO+IPXj4rwfYCtXOdl eiLFl4KoNQuVqxH1e5LrrlgDqqRf3mbSkpMMHnP5kFfGsALvLZwo3Oj3Q/WHwMPA N90oFcZFKHLzeMANGHIHOjaDhAvaTRcyY78FpR4E3Yu91T/pLXT45zuK8GeWg74r 4el1n5/IJ+21El/jKbmJUG8Moe3qKlLTXigP8704F+o6zL/Wzliex8eBknhas9Mf fK0PgPQwRY/xkIU3PT0beXnGBXziWy85/cqGrNF2dBxWYXY3lk7DDj+HjFfyhkJQ == X-ME-Sender: X-ME-Proxy-Cause: gggruggvucftvghtrhhoucdtuddrgedugedrheeggdduvdegucetufdoteggodetrfdotf fvucfrrhhofhhilhgvmecuhfgrshhtofgrihhlpdfqfgfvpdfurfetoffkrfgpnffqhgen uceurghilhhouhhtmecufedttdenucenucfjughrpefuvffhfffkgggtgfesthekredttd dtlfenucfhrhhomhepoehgrhgvghhkhheslhhinhhugihfohhunhgurghtihhonhdrohhr gheqnecukfhppeekfedrkeeirdekledruddtjeenucevlhhushhtvghrufhiiigvpedune curfgrrhgrmhepmhgrihhlfhhrohhmpehgrhgvgheskhhrohgrhhdrtghomh X-ME-Proxy: Received: from localhost (83-86-89-107.cable.dynamic.v4.ziggo.nl [83.86.89.107]) by mail.messagingengine.com (Postfix) with ESMTPA id 634E330607B0; Fri, 7 Feb 2020 03:46:41 -0500 (EST) Subject: FAILED: patch "[PATCH] padata: Remove broken queue flushing" failed to apply to 4.9-stable tree To: herbert@gondor.apana.org.au, daniel.m.jordan@oracle.com, stable@vger.kernel.org Cc: From: Date: Fri, 07 Feb 2020 09:46:32 +0100 Message-ID: <1581065192241173@kroah.com> MIME-Version: 1.0 Content-Type: text/plain; charset=ANSI_X3.4-1968 Content-Transfer-Encoding: 8bit Sender: stable-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org The patch below does not apply to the 4.9-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to . thanks, greg k-h ------------------ original commit in Linus's tree ------------------ >From 07928d9bfc81640bab36f5190e8725894d93b659 Mon Sep 17 00:00:00 2001 From: Herbert Xu Date: Tue, 19 Nov 2019 13:17:31 +0800 Subject: [PATCH] padata: Remove broken queue flushing The function padata_flush_queues is fundamentally broken because it cannot force padata users to complete the request that is underway. IOW padata has to passively wait for the completion of any outstanding work. As it stands flushing is used in two places. Its use in padata_stop is simply unnecessary because nothing depends on the queues to be flushed afterwards. The other use in padata_replace is more substantial as we depend on it to free the old pd structure. This patch instead uses the pd->refcnt to dynamically free the pd structure once all requests are complete. Fixes: 2b73b07ab8a4 ("padata: Flush the padata queues actively") Cc: Signed-off-by: Herbert Xu Reviewed-by: Daniel Jordan Signed-off-by: Herbert Xu diff --git a/kernel/padata.c b/kernel/padata.c index c3fec1413295..da56a235a255 100644 --- a/kernel/padata.c +++ b/kernel/padata.c @@ -35,6 +35,8 @@ #define MAX_OBJ_NUM 1000 +static void padata_free_pd(struct parallel_data *pd); + static int padata_index_to_cpu(struct parallel_data *pd, int cpu_index) { int cpu, target_cpu; @@ -283,6 +285,7 @@ static void padata_serial_worker(struct work_struct *serial_work) struct padata_serial_queue *squeue; struct parallel_data *pd; LIST_HEAD(local_list); + int cnt; local_bh_disable(); squeue = container_of(serial_work, struct padata_serial_queue, work); @@ -292,6 +295,8 @@ static void padata_serial_worker(struct work_struct *serial_work) list_replace_init(&squeue->serial.list, &local_list); spin_unlock(&squeue->serial.lock); + cnt = 0; + while (!list_empty(&local_list)) { struct padata_priv *padata; @@ -301,9 +306,12 @@ static void padata_serial_worker(struct work_struct *serial_work) list_del_init(&padata->list); padata->serial(padata); - atomic_dec(&pd->refcnt); + cnt++; } local_bh_enable(); + + if (atomic_sub_and_test(cnt, &pd->refcnt)) + padata_free_pd(pd); } /** @@ -440,7 +448,7 @@ static struct parallel_data *padata_alloc_pd(struct padata_instance *pinst, padata_init_squeues(pd); atomic_set(&pd->seq_nr, -1); atomic_set(&pd->reorder_objects, 0); - atomic_set(&pd->refcnt, 0); + atomic_set(&pd->refcnt, 1); spin_lock_init(&pd->lock); pd->cpu = cpumask_first(pd->cpumask.pcpu); INIT_WORK(&pd->reorder_work, invoke_padata_reorder); @@ -466,29 +474,6 @@ static void padata_free_pd(struct parallel_data *pd) kfree(pd); } -/* Flush all objects out of the padata queues. */ -static void padata_flush_queues(struct parallel_data *pd) -{ - int cpu; - struct padata_parallel_queue *pqueue; - struct padata_serial_queue *squeue; - - for_each_cpu(cpu, pd->cpumask.pcpu) { - pqueue = per_cpu_ptr(pd->pqueue, cpu); - flush_work(&pqueue->work); - } - - if (atomic_read(&pd->reorder_objects)) - padata_reorder(pd); - - for_each_cpu(cpu, pd->cpumask.cbcpu) { - squeue = per_cpu_ptr(pd->squeue, cpu); - flush_work(&squeue->work); - } - - BUG_ON(atomic_read(&pd->refcnt) != 0); -} - static void __padata_start(struct padata_instance *pinst) { pinst->flags |= PADATA_INIT; @@ -502,10 +487,6 @@ static void __padata_stop(struct padata_instance *pinst) pinst->flags &= ~PADATA_INIT; synchronize_rcu(); - - get_online_cpus(); - padata_flush_queues(pinst->pd); - put_online_cpus(); } /* Replace the internal control structure with a new one. */ @@ -526,8 +507,8 @@ static void padata_replace(struct padata_instance *pinst, if (!cpumask_equal(pd_old->cpumask.cbcpu, pd_new->cpumask.cbcpu)) notification_mask |= PADATA_CPU_SERIAL; - padata_flush_queues(pd_old); - padata_free_pd(pd_old); + if (atomic_dec_and_test(&pd_old->refcnt)) + padata_free_pd(pd_old); if (notification_mask) blocking_notifier_call_chain(&pinst->cpumask_change_notifier,