From mboxrd@z Thu Jan 1 00:00:00 1970 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 1WmMZg-0006EK-3L for linux-mtd@lists.infradead.org; Mon, 19 May 2014 12:21:48 +0000 Date: Mon, 19 May 2014 09:20:52 -0300 From: Ezequiel Garcia To: "Gupta, Pekon" Subject: Re: [PATCH v2] mtd: nand: omap: fix BCHx ecc.correct to return detected bit-flips in erased-page Message-ID: <20140519122052.GA698@arch.cereza> References: <1395730699-14687-1-git-send-email-pekon@ti.com> <20140512203626.GS28907@ld-irv-0074> <20980858CB6D3A4BAE95CA194937D5E73EACDE66@DBDE04.ent.ti.com> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20980858CB6D3A4BAE95CA194937D5E73EACDE66@DBDE04.ent.ti.com> Cc: Stefan Roese , Brian Norris , linux-mtd List-Id: Linux MTD discussion mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Hi Pekon, On 19 May 05:00 AM, Gupta, Pekon wrote: > >From: Brian Norris [mailto:computersforpeace@gmail.com] > > > >On Tue, Mar 25, 2014 at 12:28:19PM +0530, Pekon Gupta wrote: > >> fixes: commit 62116e5171e00f85a8d53f76e45b84423c89ff34 > >> mtd: nand: omap2: Support for hardware BCH error correction. > >> > >> In omap_elm_correct_data(), if bitflip_count in an erased-page is within the > >> correctable limit (< ecc.strength), then it is not indicated back to the caller > >> ecc->read_page(). > >> This mis-guides upper layers like MTD and UBIFS layer to assume erased-page as > >> perfectly clean and use it for writing even if actual bitflip_count was > >> dangerously high (bitflip_count > mtd->bitflip_threshold). > >> > >> This patch fixes this above issue, by returning 'stats' to caller > >> ecc->read_page() under all scenarios. > >> > >> Reported-by: Brian Norris > >> Signed-off-by: Pekon Gupta > > > >Pushed to l2-mtd.git. Thanks! > > > > Just forgot to ask, Is this patch candidate for stable? > > This one fixes the long standing issue of returning bit-flip count of an > erased-page to upper layers. So that upper layers take correct decision. > Yes, if the commit fixes a bug then it can be marked for stable. There's some instructions on this subject, please take a look at [1] and [2]. I think this patch qualifies the stable rules. In particular, if a patch fixes a bug and you know the culprit commit you can add a Fixes tag to pass such information, with a 12-digit commit ID and the commit title enclosed in double-quotes [1]: Fixes: 62116e5171e0 ("mtd: nand: omap2: Support for hardware BCH error correction") To mark it for stable [2], you need add a Cc tag like this: Cc: # 3.x.y You can use something like this to find the releases that contain the bug: git tag -l --contains 62116e5171e0 | grep ^v3 It's handy to add that as a git alias: [alias] .. ontags = !sh -c 'git tag -l --contains $1 | grep ^v[23]' - However, now that Brian has pushed the patch, you don't need to do any of this. AFAIK, maintainers usually take care of all the above. [1] Documentation/SubmittingPatches [2] Documentation/stable_kernel_rules.txt. Hope this helps, -- Ezequiel García, Free Electrons Embedded Linux, Kernel and Android Engineering http://free-electrons.com