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=-7.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,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 B8457C43381 for ; Fri, 15 Feb 2019 19:56:53 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 940C9222D7 for ; Fri, 15 Feb 2019 19:56:53 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2388102AbfBOT4w (ORCPT ); Fri, 15 Feb 2019 14:56:52 -0500 Received: from mga01.intel.com ([192.55.52.88]:61804 "EHLO mga01.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726749AbfBOT4v (ORCPT ); Fri, 15 Feb 2019 14:56:51 -0500 X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from fmsmga002.fm.intel.com ([10.253.24.26]) by fmsmga101.fm.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 15 Feb 2019 11:56:51 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.58,373,1544515200"; d="scan'208";a="143852650" Received: from dwillia2-desk3.jf.intel.com (HELO dwillia2-desk3.amr.corp.intel.com) ([10.54.39.16]) by fmsmga002.fm.intel.com with ESMTP; 15 Feb 2019 11:56:51 -0800 Subject: [PATCH v2 5/6] nfit/ars: Allow root to busy-poll the ARS state machine From: Dan Williams To: linux-nvdimm@lists.01.org Cc: Erwin Tsaur , vishal.l.verma@intel.com, linux-kernel@vger.kernel.org Date: Fri, 15 Feb 2019 11:44:13 -0800 Message-ID: <155025985341.1043225.5482732552253707094.stgit@dwillia2-desk3.amr.corp.intel.com> In-Reply-To: <155025982726.1043225.15436410616433285475.stgit@dwillia2-desk3.amr.corp.intel.com> References: <155025982726.1043225.15436410616433285475.stgit@dwillia2-desk3.amr.corp.intel.com> User-Agent: StGit/0.18-2-gc94f MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org The ARS implementation implements exponential back-off on the poll interval to prevent high-frequency access to the DIMM / platform interface. Depending on when the ARS completes the poll interval may exceed the completion event by minutes. Allow root to reset the timeout each time it probes the status. A one-second timeout is still enforced, but root can otherwise can control the poll interval. Reported-by: Erwin Tsaur Signed-off-by: Dan Williams --- drivers/acpi/nfit/core.c | 8 ++++++++ drivers/acpi/nfit/nfit.h | 1 + 2 files changed, 9 insertions(+) diff --git a/drivers/acpi/nfit/core.c b/drivers/acpi/nfit/core.c index 90312892093e..629cf91649d2 100644 --- a/drivers/acpi/nfit/core.c +++ b/drivers/acpi/nfit/core.c @@ -1333,6 +1333,13 @@ static ssize_t scrub_show(struct device *dev, busy = test_bit(ARS_BUSY, &acpi_desc->scrub_flags) && !test_bit(ARS_CANCEL, &acpi_desc->scrub_flags); rc = sprintf(buf, "%d%s", acpi_desc->scrub_count, busy ? "+\n" : "\n"); + /* Allow an admin to poll the busy state at a higher rate */ + if (busy && capable(CAP_SYS_RAWIO) && !test_and_set_bit(ARS_POLL, + &acpi_desc->scrub_flags)) { + acpi_desc->scrub_tmo = 1; + mod_delayed_work(nfit_wq, &acpi_desc->dwork, HZ); + } + mutex_unlock(&acpi_desc->init_mutex); device_unlock(dev); return rc; @@ -3187,6 +3194,7 @@ static void acpi_nfit_scrub(struct work_struct *work) else notify_ars_done(acpi_desc); memset(acpi_desc->ars_status, 0, acpi_desc->max_ars); + clear_bit(ARS_POLL, &acpi_desc->scrub_flags); mutex_unlock(&acpi_desc->init_mutex); } diff --git a/drivers/acpi/nfit/nfit.h b/drivers/acpi/nfit/nfit.h index 897ce10192a0..d14bad687fb8 100644 --- a/drivers/acpi/nfit/nfit.h +++ b/drivers/acpi/nfit/nfit.h @@ -213,6 +213,7 @@ struct nfit_mem { enum scrub_flags { ARS_BUSY, ARS_CANCEL, + ARS_POLL, }; struct acpi_nfit_desc {