From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.nokia.com ([192.100.122.230] helo=mgw-mx03.nokia.com) by bombadil.infradead.org with esmtps (Exim 4.69 #1 (Red Hat Linux)) id 1MRPxb-0004UC-Ih for linux-mtd@lists.infradead.org; Thu, 16 Jul 2009 12:21:20 +0000 Subject: Re: block2mtd and ubi are initialized too early when compiled in on 2.6.31-rc2 From: Artem Bityutskiy To: Tobias Diedrich In-Reply-To: <20090715115235.GA21888@yamamaya.is-a-geek.org> References: <20090715115235.GA21888@yamamaya.is-a-geek.org> Content-Type: text/plain; charset="UTF-8" Date: Thu, 16 Jul 2009 15:20:44 +0300 Message-Id: <1247746844.11353.152.camel@localhost.localdomain> Mime-Version: 1.0 Content-Transfer-Encoding: 8bit Cc: linux-mtd@lists.infradead.org, linux-kernel@vger.kernel.org Reply-To: dedekind@infradead.org List-Id: Linux MTD discussion mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Hi, On Wed, 2009-07-15 at 13:52 +0200, Tobias Diedrich wrote: > On 2.6.31-rc2 the block2mtd drivers module_init is called before any > block devices have been registered. Hmm, ok. Is this because block devices are registered asynchronously? Could you please point to the code where it is done, just for reference. > Also ubi is initialized pretty early and fails completely if an mtd > specified on the command line could not be found. Hmm... > IMO ubi should at least complete initialization so that attaching > the mtd later with ubiattach would still work. > I'm working around this two hacky patches that create a kernel > thread and retry every second for 20 seconds when the first try > doesn't work. > (Obviously this means rootdelay=$somenumber is needed) > I tried using the async infrastructure, but apparently > async_synchronize_full is called somewhere between registering the > async probe thread and the target USB device being registered by the > USB subsystem, which halts boot until my 20 second timeout, and the > USB stick is only detected afterwards. > > FWIW I want to use a erasesize aware FS on my USB stick (whose > builtin FTL has abysmal write performance if writes are less than > the erasesize) and also be able to use this as my root fs. > So my setup is usb_storage->block2mtd->ubi->ubifs Hmm, how other subsystems solve this problem? Any pointer to the code? -- Best regards, Artem Bityutskiy (Битюцкий Артём)