From patchwork Sun Aug 15 15:08:24 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: =?utf-8?q?Krzysztof_Wilczy=C5=84ski?= X-Patchwork-Id: 12437321 X-Patchwork-Delegate: bhelgaas@google.com 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=-16.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,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 C16E6C4338F for ; Sun, 15 Aug 2021 15:08:28 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 9A4B361208 for ; Sun, 15 Aug 2021 15:08:28 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232896AbhHOPI5 (ORCPT ); Sun, 15 Aug 2021 11:08:57 -0400 Received: from mail-lj1-f176.google.com ([209.85.208.176]:41808 "EHLO mail-lj1-f176.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229603AbhHOPI5 (ORCPT ); Sun, 15 Aug 2021 11:08:57 -0400 Received: by mail-lj1-f176.google.com with SMTP id h9so23338028ljq.8 for ; Sun, 15 Aug 2021 08:08:26 -0700 (PDT) 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:mime-version :content-transfer-encoding; bh=D5fDOg5hsVZqctxAJ1KqBrrp45rGk2Hwe8BSRjMZN1Y=; b=XP9nsdiy37cBjhNGXPqvIdjgPQcjvCZVkYDuQDwnZeoomIx4oT/UA0lMNXEW0RYZ1A C8q5J4ej0XVXVMyQbqF+E3ov1ySEOIzZqDngy41uJNTjqiSdp3bo/Iw9llCM9enBOj9i ErM9rOpfTc96SSrGk3bp4chCRBE0FZ1eGCgKNOAgRbMhIMb98YaWR6/dFKk31wpAIIvM UAtxdQZ4Zy7rUVEKvii0L3ac4nZqCC+WQUa1545PnacglH87cOPXKlt/EBdIn70+e4Ae JU9CDEbIPitfXxx0wOW9nzi3ZMTlroTLMQ+Xdj9FkUURwgM8yyllY4CEdRU7+5pNkKOE EH9Q== X-Gm-Message-State: AOAM530S9apuatLBGRHdwu7RMo1QWnsoyVzUbHGJYFxsuFn6HoZx8zwF YzscAI462fPJr80difkM5KI= X-Google-Smtp-Source: ABdhPJwpF0cemkUw4FZX68VO7kjRHFP9AxEZ0Jp0ACe/KDRok7UQqu2zprcNtJlgrcQAIWFJUBNbwQ== X-Received: by 2002:a2e:7411:: with SMTP id p17mr8986860ljc.104.1629040106245; Sun, 15 Aug 2021 08:08:26 -0700 (PDT) Received: from workstation.lan ([95.155.85.46]) by smtp.gmail.com with ESMTPSA id m5sm641831ljg.55.2021.08.15.08.08.25 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sun, 15 Aug 2021 08:08:25 -0700 (PDT) From: =?utf-8?q?Krzysztof_Wilczy=C5=84ski?= To: Bjorn Helgaas Cc: Bin Lai , Jiang Biao , linux-pci@vger.kernel.org Subject: [PATCH] PCI: Allow scheduling to take place in proc_bus_pci_read() Date: Sun, 15 Aug 2021 15:08:24 +0000 Message-Id: <20210815150824.96773-1-kw@linux.com> X-Mailer: git-send-email 2.32.0 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-pci@vger.kernel.org PCI configuration space reads from the /proc/bus/pci for a particular device, depending on the underlying hardware, can often take several milliseconds to complete. Thus, add a schedule point in proc_bus_pci_read() to reduce the maximum latency. A similar change has already been completed in the past for the sysfs counterpart in the commit 2ce02a864ac1 ("PCI: Add schedule point in pci_read_config()"). Link: https://lore.kernel.org/r/20200824052025.48362-1-benbjiang@tencent.com Signed-off-by: Krzysztof Wilczyński --- drivers/pci/proc.c | 1 + 1 file changed, 1 insertion(+) diff --git a/drivers/pci/proc.c b/drivers/pci/proc.c index d32fbfc93ea9..cb18f8a13ab6 100644 --- a/drivers/pci/proc.c +++ b/drivers/pci/proc.c @@ -83,6 +83,7 @@ static ssize_t proc_bus_pci_read(struct file *file, char __user *buf, buf += 4; pos += 4; cnt -= 4; + cond_resched(); } if (cnt >= 2) {