From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from mailout4.w1.samsung.com ([210.118.77.14]:32146 "EHLO mailout4.w1.samsung.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1030553Ab2HIOyr (ORCPT ); Thu, 9 Aug 2012 10:54:47 -0400 Message-id: <5023CF31.4010209@samsung.com> Date: Thu, 09 Aug 2012 16:54:41 +0200 From: Tomasz Stanislawski MIME-version: 1.0 To: Greg KH Cc: linux-media@vger.kernel.org, dri-devel@lists.freedesktop.org, airlied@redhat.com, m.szyprowski@samsung.com, kyungmin.park@samsung.com, laurent.pinchart@ideasonboard.com, sumit.semwal@linaro.org, inki.dae@samsung.com, daniel.vetter@ffwll.ch, rob@ti.com, pawel@osciak.com, linaro-mm-sig@lists.linaro.org, linux-kernel@vger.kernel.org, jy0922.shim@samsung.com, sw0312.kim@samsung.com, dan.j.williams@intel.com, linux-doc@vger.kernel.org Subject: Re: [PATCH v2 1/2] dma-buf: add reference counting for exporter module References: <1344504982-30415-1-git-send-email-t.stanislaws@samsung.com> <1344504982-30415-2-git-send-email-t.stanislaws@samsung.com> <20120809142346.GA17402@kroah.com> In-reply-to: <20120809142346.GA17402@kroah.com> Content-type: text/plain; charset=ISO-8859-1 Content-transfer-encoding: 7bit Sender: linux-media-owner@vger.kernel.org List-ID: Hi Greg, On 08/09/2012 04:23 PM, Greg KH wrote: > On Thu, Aug 09, 2012 at 11:36:21AM +0200, Tomasz Stanislawski wrote: >> This patch adds reference counting on a module that exported dma-buf and >> implements its operations. This prevents the module from being unloaded while >> DMABUF file is in use. > > Why force all of the modules to be changed "by hand", and not just do > this automatically by changing the register function to include the > THIS_MODULE macro in it? Much like the pci_register_driver() function > is implemented in include/linux/pci.h? Thank you for the hint. The owner field belongs to dma_buf_ops structure that is often a 'const' entity. Therefore owner field would have to be moved to 'struct dma_buf' to avoid 'deconstification' issues. Regards, Tomasz Stanislawski > > That makes it impossible for driver authors to get it wrong, which is > always a good sign of a correct api. > > thanks, > > greg k-h >