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=-9.9 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_GIT 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 C8E7DC43331 for ; Tue, 31 Mar 2020 01:32:37 +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 96D142072A for ; Tue, 31 Mar 2020 01:32:37 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="fwNpqSvc" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 96D142072A 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=ZZdMxbLY9oAxB4TLdGvNOZRZwWNE31JotDmNDEcs2oc=; b=fwNpqSvci0wmJw 06YHs9RUy5RInhLejG/VyJl/7ZLgTxpsb4Sj5fUvtEi3MGPS8oBR1+hIcayK57kK14NxWW3e1DQCu GcKJrq7iEkGwHtt5bDrJvBzIOjBgLVSKWaLAgNwnnAks+OQTfSxUdwVEN6zmyvsTTMcN0qfJrxCEX n54g8BEDGjvyTjs/LMmibqPTxCyR66xcwLNIVjrhGc3rN+sIAO7nTHgnCf7OmXTz2x/l1GiC17Ld3 O6qb2sbJ2A4JdR3OUvCKXdQd4aqGAqSbnh6EnnqyfFrKXGgMXHGbU0yYDlc6xnB6YmfDf8yzpNpJY OFVT4vPz/NcF9QDn1x2g==; 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 1jJ5lP-0002vC-PH; Tue, 31 Mar 2020 01:32:23 +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 1jJ5lJ-0002uB-RY for linux-mtd@lists.infradead.org; Tue, 31 Mar 2020 01:32:19 +0000 Received: from DGGEMS409-HUB.china.huawei.com (unknown [172.30.72.59]) by Forcepoint Email with ESMTP id 38501D422F8AFB709CCE; Tue, 31 Mar 2020 09:32:08 +0800 (CST) Received: from use12-sp2.huawei.com (10.67.189.174) by DGGEMS409-HUB.china.huawei.com (10.3.19.209) with Microsoft SMTP Server id 14.3.487.0; Tue, 31 Mar 2020 09:32:01 +0800 From: Xiaoming Ni To: , , , Subject: [PATCH v4] mtd: clear cache_state to avoid writing to bad blocks repeatedly Date: Tue, 31 Mar 2020 09:31:59 +0800 Message-ID: <1585618319-119741-1-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-20200330_183218_077795_613DB933 X-CRM114-Status: GOOD ( 12.43 ) 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 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; } -- 1.8.5.6 ______________________________________________________ Linux MTD discussion mailing list http://lists.infradead.org/mailman/listinfo/linux-mtd/