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=-9.8 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,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 0FB11C43331 for ; Sat, 28 Mar 2020 13:02:10 +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 D29C8206F6 for ; Sat, 28 Mar 2020 13:02:09 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="J0XL4PTc" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org D29C8206F6 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-Transfer-Encoding:Content-Type:Cc:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:MIME-Version:Message-ID:Date:Subject:To :From:Reply-To:Content-ID:Content-Description:Resent-Date:Resent-From: Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:In-Reply-To:References: List-Owner; bh=n5ad0dvrGS8xVK248Yv393eiirY9bcYmgbTpl+8Yljw=; b=J0XL4PTcohc9Md KPZxiD+H9HGGJ0+FkuWkk8hHXF6aRzQkmmt8ybAqkdzu0E5ED55h/G63BZYs5Wew8KashTnKVcS5y 5pj64tziJXUArjurDkylpb3laGCfjCSSeyMHqHu3VFXw/PaHbeFj8t5MSUZMI7LGx3v91bCge0ia/ ZRylExLP55E38/aiXd4fgRmu3EcfRANr62PKHsTEq78HKtFHycoNwrJ2u2Q6degWQnzp+zeCJgqO8 l69r4kT/PxrT1lruKdPIhAbS1P6AwsyrBlrkC/LFZGpyTIjKtdV7XAr/FN1w/R/ri759JChpI7N0I eR6culeqY0GEsK4sbdOg==; 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 1jIB5z-00063p-FU; Sat, 28 Mar 2020 13:01:51 +0000 Received: from szxga06-in.huawei.com ([45.249.212.32] helo=huawei.com) by bombadil.infradead.org with esmtps (Exim 4.92.3 #3 (Red Hat Linux)) id 1jIB5r-00062A-O1 for linux-mtd@lists.infradead.org; Sat, 28 Mar 2020 13:01:45 +0000 Received: from DGGEMS404-HUB.china.huawei.com (unknown [172.30.72.58]) by Forcepoint Email with ESMTP id CC0D1DB02DE44016DCAE; Sat, 28 Mar 2020 21:01:26 +0800 (CST) Received: from use12-sp2.huawei.com (10.67.189.174) by DGGEMS404-HUB.china.huawei.com (10.3.19.204) with Microsoft SMTP Server id 14.3.487.0; Sat, 28 Mar 2020 21:01:20 +0800 From: Xiaoming Ni To: , , Subject: [PATCH] mtd:clear cache_state to avoid writing to bad clocks repeatedly Date: Sat, 28 Mar 2020 21:01:17 +0800 Message-ID: <1585400477-65705-1-git-send-email-nixiaoming@huawei.com> X-Mailer: git-send-email 1.8.5.6 MIME-Version: 1.0 X-Originating-IP: [10.67.189.174] X-CFilter-Loop: Reflected X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20200328_060144_356673_E54270EB X-CRM114-Status: GOOD ( 12.47 ) 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, nixiaoming@huawei.com, yebin10@huawei.com Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-mtd" Errors-To: linux-mtd-bounces+linux-mtd=archiver.kernel.org@lists.infradead.org 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 clocks repeatedly. Signed-off-by: Xiaoming Ni --- 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..98c25d6 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 clocks repeatedly */ - mtdblk->cache_state = STATE_EMPTY; - return 0; + if (ret == 0 || ret == -EIO) + mtdblk->cache_state = STATE_EMPTY; + return ret; } -- 1.8.5.6 ______________________________________________________ Linux MTD discussion mailing list http://lists.infradead.org/mailman/listinfo/linux-mtd/