From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Darrick J. Wong" Subject: Re: [PATCH v3] libsas: move ATA bits into a separate module Date: Thu, 14 Sep 2006 15:40:55 -0700 Message-ID: <4509DA77.7000508@us.ibm.com> References: <4508A0A2.2080605@us.ibm.com> <450971D3.2040405@garzik.org> Reply-To: "Darrick J. Wong" Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Return-path: Received: from e2.ny.us.ibm.com ([32.97.182.142]:26333 "EHLO e2.ny.us.ibm.com") by vger.kernel.org with ESMTP id S932079AbWINWk7 (ORCPT ); Thu, 14 Sep 2006 18:40:59 -0400 In-Reply-To: <450971D3.2040405@garzik.org> Sender: linux-ide-owner@vger.kernel.org List-Id: linux-ide@vger.kernel.org To: Jeff Garzik , linux-ide Cc: linux-scsi , Linux Kernel Mailing List , Alexis Bruemmer , Mike Anderson Jeff Garzik wrote: > I disagree completely with this approach. > > You don't need a table of hooks for the case where libata is disabled in > .config. Thus, it's only useful for the case where libsas is loaded as > a module, but libata is not. Indeed, I misunderstood what James Bottomley wanted, so I reworked the patch. It has the same functionality as before, but this module uses the module loader/symbol resolver for all the functions in libata, and allows libsas to (optionally) call into sas_ata with weak references by pushing a table of the necessary function pointers into libsas at sas_ata load time. Thus, libsas doesn't need to load libata/sas_ata unless it actually finds a SATA device. > The libsas code should directly call libata functions. If ATA support > in libsas is disabled in .config, then those functions will never be > called, thus never loaded the libata module. I certainly can (and now do) call libata functions from sas_ata. However, there are a few cases where libsas needs to call libata (ex. sas_ioctl); for those cases, I think the function pointers are still necessary because I don't want to make libsas require libata. In any case, if ATA support is disabled in .config, sata_is_dev always returns 0, so the dead-code eliminator should zap that out of libsas entirely. As usual, thank you for any feedback that you have. Link to version 3: http://sweaglesw.net/~djwong/docs/sas-ata_3.patch --D Signed-off-by: Darrick J. Wong