From patchwork Mon Mar 30 13:11:09 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Xiaoming Ni X-Patchwork-Id: 1263943 X-Patchwork-Delegate: miquel.raynal@bootlin.com Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Authentication-Results: ozlabs.org; spf=none (no SPF record) smtp.mailfrom=lists.infradead.org (client-ip=2607:7c80:54:e::133; helo=bombadil.infradead.org; envelope-from=linux-mtd-bounces+incoming=patchwork.ozlabs.org@lists.infradead.org; receiver=) Authentication-Results: ozlabs.org; dmarc=none (p=none dis=none) header.from=huawei.com Authentication-Results: ozlabs.org; dkim=pass (2048-bit key; unprotected) header.d=lists.infradead.org header.i=@lists.infradead.org header.a=rsa-sha256 header.s=bombadil.20170209 header.b=Y11XvXBw; dkim-atps=neutral Received: from bombadil.infradead.org (bombadil.infradead.org [IPv6:2607:7c80:54:e::133]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256) (No client certificate requested) by ozlabs.org (Postfix) with ESMTPS id 48rXt21KNYz9sP7 for ; Tue, 31 Mar 2020 00:11:54 +1100 (AEDT) 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=Y11XvXBwzPxFFV MrVVQ8AZq4V1NaFpjebnYQmM6nSIy8yRWPtOR0CvZv0ypmhOlXuDbPq/2vwRLFgtBMx3p6Mfpwouw J0gCvQdQIaiFiS/uqrDFZxXc/cMqrZlTmG7yM4VQgHIflsZBDBENVQD4Qs00ixh+aRxtuio3Hf2Is pxqIFpFgthNP3zNeXsm3HbLCWGQOR2TB9IWJLhhNKnhSqNPdmDmWtF68vQoXG1Qem1TD5NBQh8JSY 34+E/QlBvuS/F91wFkkAuDz9R44He2tyGIxhjhKok09pF7qe0L3P125Ph3yxT3rI7rQfXv+3tx5js btrRqWiHFKqJ/0Q75UuA==; 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 1jIuCR-0002QW-VS; Mon, 30 Mar 2020 13:11:31 +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 1jIuCN-0002Jk-Dj for linux-mtd@lists.infradead.org; Mon, 30 Mar 2020 13:11:29 +0000 Received: from DGGEMS412-HUB.china.huawei.com (unknown [172.30.72.60]) by Forcepoint Email with ESMTP id 26A80442C2BD11412B18; Mon, 30 Mar 2020 21:11:23 +0800 (CST) Received: from use12-sp2.huawei.com (10.67.189.174) by DGGEMS412-HUB.china.huawei.com (10.3.19.212) with Microsoft SMTP Server id 14.3.487.0; Mon, 30 Mar 2020 21:11:12 +0800 From: Xiaoming Ni To: , , Subject: [PATCH v2] mtd:clear cache_state to avoid writing to bad blocks repeatedly Date: Mon, 30 Mar 2020 21:11:09 +0800 Message-ID: <1585573869-81863-1-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_061127_648834_AB839960 X-CRM114-Status: GOOD ( 12.26 ) X-Spam-Score: -2.3 (--) X-Spam-Report: SpamAssassin version 3.4.4 on bombadil.infradead.org summary: Content analysis details: (-2.3 points) pts rule name description ---- ---------------------- -------------------------------------------------- -2.3 RCVD_IN_DNSWL_MED RBL: Sender listed at https://www.dnswl.org/, medium trust [45.249.212.32 listed in list.dnswl.org] -0.0 SPF_HELO_PASS SPF: HELO matches SPF record -0.0 SPF_PASS SPF: sender matches SPF record 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 Sender: "linux-mtd" Errors-To: linux-mtd-bounces+incoming=patchwork.ozlabs.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; }