Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755058Ab0LOTT1 (ORCPT ); Wed, 15 Dec 2010 14:19:27 -0500 Received: from hera.kernel.org ([140.211.167.34]:59277 "EHLO hera.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754614Ab0LOTTY (ORCPT ); Wed, 15 Dec 2010 14:19:24 -0500 Message-ID: <4D0914B5.20208@kernel.org> Date: Wed, 15 Dec 2010 20:19:17 +0100 From: Tejun Heo User-Agent: Mozilla/5.0 (X11; U; Linux x86_64; en-US; rv:1.9.2.13) Gecko/20101209 Fedora/3.1.7-0.35.b3pre.fc14 Lightning/1.0b2 Thunderbird/3.1.7 MIME-Version: 1.0 To: James Bottomley CC: Linux SCSI List , FUJITA Tomonori , lkml Subject: Re: [PATCH 2/2] scsi: don't use execute_in_process_context() References: <4CBD95C0.6060302@kernel.org> <4CBD95DC.8000001@kernel.org> <1292194113.2989.9.camel@mulgrave.site> <4D073E9A.3000608@kernel.org> <1292335754.3058.2.camel@mulgrave.site> <4D077CD9.6050907@kernel.org> <1292336798.3058.5.camel@mulgrave.site> <4D078052.3040800@kernel.org> <1292382245.19511.56.camel@mulgrave.site> <4D08E2FF.5090605@kernel.org> <1292428486.4688.180.camel@mulgrave.site> <4D08E624.3020808@kernel.org> <1292433773.4688.278.camel@mulgrave.site> <4D09116C.6010508@kernel.org> <1292440246.4688.416.camel@mulgrave.site> In-Reply-To: <1292440246.4688.416.camel@mulgrave.site> X-Enigmail-Version: 1.1.2 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.2.3 (hera.kernel.org [127.0.0.1]); Wed, 15 Dec 2010 19:19:19 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1671 Lines: 42 Hello, On 12/15/2010 08:10 PM, James Bottomley wrote: >> Yes, it would do, but we were already too far with the existing >> implementation and I don't agree we need more when replacing it with >> usual workqueue usage would remove the issue. So, when we actually >> need them, let's consider that or any other way to do it, please. >> A core API with only a few users which can be easily replaced isn't >> really worth keeping around. Wouldn't you agree? > > Not really ... since the fix is small and obvious. IMHO, it's a bit too subtle to be a good API. The callee is called under different (locking) context depending on the callsite and I've been already bitten enough times from implicit THIS_MODULEs. Both properties increase possbility of introducing problems which can be quite difficult to detect and reproduce. > Plus now it can't be moved into SCSI because I need the unremovable > call chain. Yes, with the proposed change, it cannot be moved to SCSI. > Show me how you propose to fix it differently first, since we both agree > the initial attempt doesn't work, and we can take the discussion from > there. Given that the structures containing the work items are dynamically allocated, I would introduce a scsi_wq, unconditionally schedule release works on them and flush them before unloading. Please note that workqueues no longer require dedicated threads, so it's quite cheap. Thanks. -- tejun -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/