From patchwork Wed Jul 2 13:16:32 2014 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Thomas Petazzoni X-Patchwork-Id: 366373 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Received: from bombadil.infradead.org (bombadil.infradead.org [IPv6:2001:1868:205::9]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ozlabs.org (Postfix) with ESMTPS id EFD29140076 for ; Wed, 2 Jul 2014 23:19:29 +1000 (EST) Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.80.1 #2 (Red Hat Linux)) id 1X2KPf-0002mI-OL; Wed, 02 Jul 2014 13:17:27 +0000 Received: from top.free-electrons.com ([176.31.233.9] helo=mail.free-electrons.com) by bombadil.infradead.org with esmtp (Exim 4.80.1 #2 (Red Hat Linux)) id 1X2KPd-0002jS-Cs for linux-mtd@lists.infradead.org; Wed, 02 Jul 2014 13:17:26 +0000 Received: by mail.free-electrons.com (Postfix, from userid 106) id 8D1FD7FB; Wed, 2 Jul 2014 15:17:09 +0200 (CEST) X-Spam-Checker-Version: SpamAssassin 3.3.2 (2011-06-06) on mail.free-electrons.com X-Spam-Level: X-Spam-Status: No, score=-1.0 required=5.0 tests=ALL_TRUSTED,SHORTCIRCUIT, URIBL_BLOCKED shortcircuit=ham autolearn=disabled version=3.3.2 Received: from localhost (col31-4-88-188-83-94.fbx.proxad.net [88.188.83.94]) by mail.free-electrons.com (Postfix) with ESMTPSA id 1435E7E9; Wed, 2 Jul 2014 15:17:09 +0200 (CEST) From: Thomas Petazzoni To: David Woodhouse , Brian Norris Subject: [PATCH] mtd: nand: reduce the warning noise when the ECC is too weak Date: Wed, 2 Jul 2014 15:16:32 +0200 Message-Id: <1404306992-28968-1-git-send-email-thomas.petazzoni@free-electrons.com> X-Mailer: git-send-email 2.0.0 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20140702_061725_734166_3D975C2D X-CRM114-Status: GOOD ( 17.70 ) X-Spam-Score: 1.0 (+) X-Spam-Report: SpamAssassin version 3.4.0 on bombadil.infradead.org summary: Content analysis details: (1.0 points) pts rule name description ---- ---------------------- -------------------------------------------------- -0.0 T_RP_MATCHES_RCVD Envelope sender domain matches handover relay domain 1.0 SPF_SOFTFAIL SPF: sender does not match SPF record (softfail) Cc: Lior Amsalem , Thomas Petazzoni , Tawfik Bayouk , Nadav Haklai , linux-mtd@lists.infradead.org, Ezequiel Garcia X-BeenThere: linux-mtd@lists.infradead.org X-Mailman-Version: 2.1.18-1 Precedence: list List-Id: Linux MTD discussion mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , MIME-Version: 1.0 Sender: "linux-mtd" Errors-To: linux-mtd-bounces+incoming=patchwork.ozlabs.org@lists.infradead.org In commit 67a9ad9b8a6f ("mtd: nand: Warn the user if the selected ECC strength is too weak"), a check was added to inform the user when the ECC used for a NAND device is weaker than the recommended ECC advertised by the NAND chip. However, the warning uses WARN_ON(), which has two undesirable side-effects: - It just prints to the kernel log the fact that there is a warning in this file, at this line, but it doesn't explain anything about the warning itself. - It dumps a stack trace which is very noisy, for something that the user is most likely not able to fix. If a certain ECC used by the kernel is weaker than the advertised one, it's most likely to make sure the kernel uses an ECC that is compatible with the one used by the bootloader, and changing the bootloader may not necessarily be easy. Therefore, normal users would not be able to do anything to fix this very noisy warning, and will have to suffer from it at every kernel boot. At least every time I see this stack trace in my kernel boot log, I wonder what new thing is broken, just to realize that it's once again this NAND ECC warning. Therefore, this commit turns: ------------[ cut here ]------------ WARNING: CPU: 0 PID: 1 at /home/thomas/projets/linux-2.6/drivers/mtd/nand/nand_base.c:4051 nand_scan_tail+0x538/0x780() Modules linked in: CPU: 0 PID: 1 Comm: swapper Not tainted 3.16.0-rc3-dirty #4 [] (unwind_backtrace) from [] (show_stack+0x10/0x14) [] (show_stack) from [] (warn_slowpath_common+0x6c/0x8c) [] (warn_slowpath_common) from [] (warn_slowpath_null+0x1c/0x24) [] (warn_slowpath_null) from [] (nand_scan_tail+0x538/0x780) [] (nand_scan_tail) from [] (orion_nand_probe+0x224/0x2e4) [] (orion_nand_probe) from [] (platform_drv_probe+0x18/0x4c) [] (platform_drv_probe) from [] (really_probe+0x80/0x218) [] (really_probe) from [] (__driver_attach+0x98/0x9c) [] (__driver_attach) from [] (bus_for_each_dev+0x64/0x94) [] (bus_for_each_dev) from [] (bus_add_driver+0x144/0x1ec) [] (bus_add_driver) from [] (driver_register+0x78/0xf8) [] (driver_register) from [] (platform_driver_probe+0x20/0xb8) [] (platform_driver_probe) from [] (do_one_initcall+0x80/0x1d8) [] (do_one_initcall) from [] (kernel_init_freeable+0xf4/0x1b4) [] (kernel_init_freeable) from [] (kernel_init+0x8/0xec) [] (kernel_init) from [] (ret_from_fork+0x14/0x24) ---[ end trace 62f87d875aceccb4 ]--- Into the much shorter, and much more useful: nand: WARNING: MT29F2G08ABAEAWP: the ECC used on your system is too weak compared to the one required by the NAND chip Signed-off-by: Thomas Petazzoni --- drivers/mtd/nand/nand_base.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) diff --git a/drivers/mtd/nand/nand_base.c b/drivers/mtd/nand/nand_base.c index 41167e9..4f3e80c 100644 --- a/drivers/mtd/nand/nand_base.c +++ b/drivers/mtd/nand/nand_base.c @@ -4047,8 +4047,10 @@ int nand_scan_tail(struct mtd_info *mtd) ecc->layout->oobavail += ecc->layout->oobfree[i].length; mtd->oobavail = ecc->layout->oobavail; - /* ECC sanity check: warn noisily if it's too weak */ - WARN_ON(!nand_ecc_strength_good(mtd)); + /* ECC sanity check: warn if it's too weak */ + if (!nand_ecc_strength_good(mtd)) + pr_warn("WARNING: %s: the ECC used on your system is too weak compared to the one required by the NAND chip\n", + mtd->name); /* * Set the number of read / write steps for one page depending on ECC