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=-8.2 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,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 55DDFC38A24 for ; Thu, 7 May 2020 07:54:16 +0000 (UTC) Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 28A542075E for ; Thu, 7 May 2020 07:54:16 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="tPxSKz4g" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 28A542075E Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=huawei.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-mtd-bounces+linux-mtd=archiver.kernel.org@lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20170209; h=Sender:Content-Type: Content-Transfer-Encoding:Cc:List-Subscribe:List-Help:List-Post:List-Archive: List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:Date:Message-ID:From: References:To:Subject:Reply-To:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=J6kU1bJFmAOWSm0TIiMc/Z+BOhlc+PHAiGNanRVcexc=; b=tPxSKz4gNIHa8IOpvsqDf1FKw 8eKjYcGoQsEnJiijxpv5pGiLDGbZAWqVPHO5BQ5tZV8GEr0SCG9SQ+IxkNGtbcEN0+G398iPf+5ZO O2iExcbsYN9FnpeK+kil9U1aZhVBw0Es1tEqBcGZil3xRaj7lQIXEtCi8RvLJCrbySr8LYg57xGnF BWvTZP9WHZGhd75UTHUS/IhmuKQQ1llOkFK43B5i+UBOahFNr0Tp4DKP7+1xLTxhu6eWQc5LB23tY Kbs+2dl/QWfxnfUzwLf99e2oT3VsXVn2O7cA4Q+L1IBntzdz0ROEPVz7HogFwnzn3cyoYFikDtxhy sWflLGUaA==; Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1jWbM0-0007dM-77; Thu, 07 May 2020 07:54:00 +0000 Received: from szxga05-in.huawei.com ([45.249.212.191] helo=huawei.com) by bombadil.infradead.org with esmtps (Exim 4.92.3 #3 (Red Hat Linux)) id 1jWbLw-0007cj-JA for linux-mtd@lists.infradead.org; Thu, 07 May 2020 07:53:58 +0000 Received: from DGGEMS401-HUB.china.huawei.com (unknown [172.30.72.58]) by Forcepoint Email with ESMTP id 1481E6579506A334BFF2; Thu, 7 May 2020 15:53:44 +0800 (CST) Received: from [127.0.0.1] (10.67.102.197) by DGGEMS401-HUB.china.huawei.com (10.3.19.201) with Microsoft SMTP Server id 14.3.487.0; Thu, 7 May 2020 15:53:38 +0800 Subject: ping; [PATCH v4] mtd: clear cache_state to avoid writing to bad blocks repeatedly To: , , References: <1585618319-119741-1-git-send-email-nixiaoming@huawei.com> From: Xiaoming Ni Message-ID: <528b61f3-bddb-d508-8f18-37cebec9e5eb@huawei.com> Date: Thu, 7 May 2020 15:53:32 +0800 User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:68.0) Gecko/20100101 Thunderbird/68.1.2 MIME-Version: 1.0 In-Reply-To: <1585618319-119741-1-git-send-email-nixiaoming@huawei.com> X-Originating-IP: [10.67.102.197] X-CFilter-Loop: Reflected X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20200507_005356_797993_77F2DD77 X-CRM114-Status: GOOD ( 18.59 ) X-BeenThere: linux-mtd@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Linux MTD discussion mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: wangle6@huawei.com, linux-kernel@vger.kernel.org, linux-mtd@lists.infradead.org, zhangweimin12@huawei.com, houtao1@huawei.com, yebin10@huawei.com Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset="us-ascii"; Format="flowed" Sender: "linux-mtd" Errors-To: linux-mtd-bounces+linux-mtd=archiver.kernel.org@lists.infradead.org ping On 2020/3/31 9:31, Xiaoming Ni wrote: > The function call process is as follows: > mtd_blktrans_work() > while (1) > do_blktrans_request() > mtdblock_writesect() > do_cached_write() > write_cached_data() /*if cache_state is STATE_DIRTY*/ > erase_write() > > write_cached_data() returns failure without modifying cache_state > and cache_offset. So when do_cached_write() is called again, > write_cached_data() will be called again to perform erase_write() > on the same cache_offset. > > But if this cache_offset points to a bad block, erase_write() will > always return -EIO. Writing to this mtdblk is equivalent to losing > the current data, and repeatedly writing to the bad block. > > Repeatedly writing a bad block has no real benefits, > but brings some negative effects: > 1 Lost subsequent data > 2 Loss of flash device life > 3 erase_write() bad blocks are very time-consuming. For example: > the function do_erase_oneblock() in chips/cfi_cmdset_0020.c or > chips/cfi_cmdset_0002.c may take more than 20 seconds to return > > Therefore, when erase_write() returns -EIO in write_cached_data(), > clear cache_state to avoid writing to bad blocks repeatedly. > > Signed-off-by: Xiaoming Ni > Reviewed-by: Miquel Raynal > --- > drivers/mtd/mtdblock.c | 11 +++++++---- > 1 file changed, 7 insertions(+), 4 deletions(-) > > diff --git a/drivers/mtd/mtdblock.c b/drivers/mtd/mtdblock.c > index 078e0f6..32e52d8 100644 > --- a/drivers/mtd/mtdblock.c > +++ b/drivers/mtd/mtdblock.c > @@ -89,8 +89,6 @@ static int write_cached_data (struct mtdblk_dev *mtdblk) > > ret = erase_write (mtd, mtdblk->cache_offset, > mtdblk->cache_size, mtdblk->cache_data); > - if (ret) > - return ret; > > /* > * Here we could arguably set the cache state to STATE_CLEAN. > @@ -98,9 +96,14 @@ static int write_cached_data (struct mtdblk_dev *mtdblk) > * be notified if this content is altered on the flash by other > * means. Let's declare it empty and leave buffering tasks to > * the buffer cache instead. > + * > + * If this cache_offset points to a bad block, data cannot be > + * written to the device. Clear cache_state to avoid writing to > + * bad blocks repeatedly. > */ > - mtdblk->cache_state = STATE_EMPTY; > - return 0; > + if (ret == 0 || ret == -EIO) > + mtdblk->cache_state = STATE_EMPTY; > + return ret; > } > > > ______________________________________________________ Linux MTD discussion mailing list http://lists.infradead.org/mailman/listinfo/linux-mtd/