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=-11.5 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,NICE_REPLY_A, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=unavailable 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 73AE7C4727E for ; Wed, 30 Sep 2020 17:24:00 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 4ABF420754 for ; Wed, 30 Sep 2020 17:24:00 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731440AbgI3RX5 (ORCPT ); Wed, 30 Sep 2020 13:23:57 -0400 Received: from mga02.intel.com ([134.134.136.20]:38534 "EHLO mga02.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725837AbgI3RX4 (ORCPT ); Wed, 30 Sep 2020 13:23:56 -0400 IronPort-SDR: PAuC9TzZNqSxdIWFpc4DYuc8i63cdVGdB1gZ/FsnMVCYAqFhd0YTRlDaQsqrxAY36mCLOf4wAs ZAJQ2N60/nPg== X-IronPort-AV: E=McAfee;i="6000,8403,9760"; a="150157847" X-IronPort-AV: E=Sophos;i="5.77,322,1596524400"; d="scan'208";a="150157847" X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from orsmga004.jf.intel.com ([10.7.209.38]) by orsmga101.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 30 Sep 2020 10:23:56 -0700 IronPort-SDR: i/Wr/vMjVXkZ5qogz7WZNWTib8KiEGRz3nH8oSSMXjiat3fjS8SP+4r76rLDlC36IzFZqUs5N6 0O98strF7WMw== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.77,322,1596524400"; d="scan'208";a="457741574" Received: from ahunter-desktop.fi.intel.com (HELO [10.237.72.190]) ([10.237.72.190]) by orsmga004.jf.intel.com with ESMTP; 30 Sep 2020 10:23:52 -0700 Subject: Re: [PATCH] mmc: core: don't set limits.discard_granularity as 0 To: Coly Li , linux-mmc@vger.kernel.org Cc: linux-kernel@vger.kernel.org, linux-block@vger.kernel.org, Vicente Bergas , Ulf Hansson References: <20200930160854.65710-1-colyli@suse.de> From: Adrian Hunter Organization: Intel Finland Oy, Registered Address: PL 281, 00181 Helsinki, Business Identity Code: 0357606 - 4, Domiciled in Helsinki Message-ID: <5178b9e0-6b95-45ef-80f1-862de554e625@intel.com> Date: Wed, 30 Sep 2020 20:23:19 +0300 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.12.0 MIME-Version: 1.0 In-Reply-To: <20200930160854.65710-1-colyli@suse.de> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org On 30/09/20 7:08 pm, Coly Li wrote: > In mmc_queue_setup_discard() the mmc driver queue's discard_granularity > might be set as 0 (when card->pref_erase > max_discard) while the mmc > device still declares to support discard operation. This is buggy and > triggered the following kernel warning message, > > WARNING: CPU: 0 PID: 135 at __blkdev_issue_discard+0x200/0x294 > CPU: 0 PID: 135 Comm: f2fs_discard-17 Not tainted 5.9.0-rc6 #1 > Hardware name: Google Kevin (DT) > pstate: 00000005 (nzcv daif -PAN -UAO BTYPE=--) > pc : __blkdev_issue_discard+0x200/0x294 > lr : __blkdev_issue_discard+0x54/0x294 > sp : ffff800011dd3b10 > x29: ffff800011dd3b10 x28: 0000000000000000 x27: ffff800011dd3cc4 x26: ffff800011dd3e18 x25: 000000000004e69b x24: 0000000000000c40 x23: ffff0000f1deaaf0 x22: ffff0000f2849200 x21: 00000000002734d8 x20: 0000000000000008 x19: 0000000000000000 x18: 0000000000000000 x17: 0000000000000000 x16: 0000000000000000 x15: 0000000000000000 x14: 0000000000000394 x13: 0000000000000000 x12: 0000000000000000 x11: 0000000000000000 x10: 00000000000008b0 x9 : ffff800011dd3cb0 x8 : 000000000004e69b x7 : 0000000000000000 x6 : ffff0000f1926400 x5 : ffff0000f1940800 x4 : 0000000000000000 x3 : 0000000000000c40 x2 : 0000000000000008 x1 : 00000000002734d8 x0 : 0000000000000000 Call trace: > __blkdev_issue_discard+0x200/0x294 > __submit_discard_cmd+0x128/0x374 > __issue_discard_cmd_orderly+0x188/0x244 > __issue_discard_cmd+0x2e8/0x33c > issue_discard_thread+0xe8/0x2f0 > kthread+0x11c/0x120 > ret_from_fork+0x10/0x1c > ---[ end trace e4c8023d33dfe77a ]--- > > This patch fixes the issue by setting discard_granularity as SECTOR_SIZE > instead of 0 when (card->pref_erase > max_discard) is true. Now no more > complain from __blkdev_issue_discard() for the improper value of discard > granularity. > > Fixes: commit e056a1b5b67b ("mmc: queue: let host controllers specify maximum discard timeout") That "Fixes" tag is a bit misleading. For some time, the block layer had no problem with discard_granularity of zero, and blk_bio_discard_split() still doesn't (see below). static struct bio *blk_bio_discard_split(struct request_queue *q, struct bio *bio, struct bio_set *bs, unsigned *nsegs) { unsigned int max_discard_sectors, granularity; int alignment; sector_t tmp; unsigned split_sectors; *nsegs = 1; /* Zero-sector (unknown) and one-sector granularities are the same. */ granularity = max(q->limits.discard_granularity >> 9, 1U); > Reported-by: Vicente Bergas > Signed-off-by: Coly Li > Cc: Adrian Hunter > Cc: Ulf Hansson > --- > drivers/mmc/core/queue.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/drivers/mmc/core/queue.c b/drivers/mmc/core/queue.c > index 6c022ef0f84d..350d0cc4ee62 100644 > --- a/drivers/mmc/core/queue.c > +++ b/drivers/mmc/core/queue.c > @@ -190,7 +190,7 @@ static void mmc_queue_setup_discard(struct request_queue *q, > q->limits.discard_granularity = card->pref_erase << 9; > /* granularity must not be greater than max. discard */ > if (card->pref_erase > max_discard) > - q->limits.discard_granularity = 0; > + q->limits.discard_granularity = SECTOR_SIZE; > if (mmc_can_secure_erase_trim(card)) > blk_queue_flag_set(QUEUE_FLAG_SECERASE, q); > } >