From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:55605) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1fiDjk-0008CG-UH for qemu-devel@nongnu.org; Wed, 25 Jul 2018 02:57:31 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1fiDji-0005XO-0P for qemu-devel@nongnu.org; Wed, 25 Jul 2018 02:57:28 -0400 Received: from mx3-rdu2.redhat.com ([66.187.233.73]:48630 helo=mx1.redhat.com) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1fiDjh-0005Wy-Pe for qemu-devel@nongnu.org; Wed, 25 Jul 2018 02:57:25 -0400 Date: Wed, 25 Jul 2018 08:57:20 +0200 From: Igor Mammedov Message-ID: <20180725085720.55dd0669@redhat.com> In-Reply-To: <20180724211144-mutt-send-email-mst@kernel.org> References: <20180723193145.24705-1-ehabkost@redhat.com> <20180723193145.24705-3-ehabkost@redhat.com> <20180724142949.3078da82@redhat.com> <20180724123916.GC3896@localhost.localdomain> <20180724172844.5bea5a07@redhat.com> <20180724211144-mutt-send-email-mst@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [PATCH for-3.1 2/2] acpi: Decouple ACPI hotplug callbacks from HotplugHandler List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: "Michael S. Tsirkin" Cc: Eduardo Habkost , qemu-devel@nongnu.org, Marcel Apfelbaum , Xiao Guangrong , Ben Warren On Tue, 24 Jul 2018 21:14:48 +0300 "Michael S. Tsirkin" wrote: > On Tue, Jul 24, 2018 at 05:28:44PM +0200, Igor Mammedov wrote: > > On Tue, 24 Jul 2018 09:39:16 -0300 > > Eduardo Habkost wrote: > > > > > On Tue, Jul 24, 2018 at 02:29:49PM +0200, Igor Mammedov wrote: > > > > On Mon, 23 Jul 2018 16:31:45 -0300 > > > > Eduardo Habkost wrote: > > > > > > > > > The ACPI hotplug callbacks get a HotplugHandler object as > > > > > argument. This has two problems: > > > > > > > > > > 1) The functions require a TYPE_ACPI_DEVICE_IF object, but the > > > > > function prototype doesn't indicate that. It's possible to > > > > > pass an object that would make the function crash. > > > > > 2) The function does not require the object to implement > > > > > TYPE_HOTPLUG_HANDLER at all, but the function prototype > > > > > imposes that for no reason. > > > > > > > > > > Change the argument type to AcpiDeviceIf instead of > > > > > HotplugHandler. > > > > What is the motivation for this patch, > > > > do you actually get crashes? > > > > > > I didn't get crashes, but the idea for the change came when > > > Michael asked me how to get the HotplugHandler object. I was > > > going to suggest current_machine (which is also a hotplug > > > handler), when I noticed he actually needed an AcpiDeviceIf > > > object. > > > > > > The main motivation, however, is to simply make the function > > > prototypes make sense. Is there a single reason to make the ACPI > > > functions get a HotplugHandler argument instead of AcpiDeviceIf? > > I'd rather to keep current *_cb() functions as is, > > as we might actually need access to hotplug handler there and in > > that case keeping more generic hotplug handler would be better > > and it also sort of documents better what is being passed in. > > > > Also we won't have to rewrite it back from AcpiDeviceIf to > > HotplugHandler again if it's needed. > > Personally I think type-safety is important, changing APIs > isn't such a big deal. So I'd rather take Eduardo's patch unless > the patches that would need to change it back are just > round the corner. what's the status there? I don't have any patches for this part nor any plan to work on it. Ok, let's go ahead with Eduardo's patches. We can always change it back if need arises.