From mboxrd@z Thu Jan 1 00:00:00 1970 From: Laszlo Ersek Subject: Re: [PATCH linux-2.6.18-xen] blktap: make max # of tap devices a module parameter Date: Tue, 22 Feb 2011 18:34:47 +0100 Message-ID: <4D63F3B7.90108@redhat.com> References: <4D63C644.1000503@redhat.com> <4D63E918020000780003327C@vpn.id2.novell.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <4D63E918020000780003327C@vpn.id2.novell.com> List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xensource.com Errors-To: xen-devel-bounces@lists.xensource.com To: Jan Beulich Cc: "xen-devel@lists.xensource.com" List-Id: xen-devel@lists.xenproject.org On 02/22/11 16:49, Jan Beulich wrote: >>>> On 22.02.11 at 15:20, Laszlo Ersek wrote: >> Hi, >> >> should anybody still use the blktap(1) driver in linux-2.6.18-xen, the >> following patch intends to make the maximum number of tapdevs >> configurable at module insertion time. The number is clamped to [256 .. >> NR_EVENT_CHANNELS]. I removed the definition of MAX_DEV_NAME because it >> didn't seem to be used at all. >> >> Thanks for considering, >> Laszlo Ersek > > Without replacing the call to register_chrdev() with one to > __register_chrdev() (available only with 2.6.32 and newer) I > can't see how you would get beyond 256 devices with the > changes you propose. Oops, sorry; I naively assumed that minor device numbers were already covered by an earlier change. I figure register_chrdev() could be reimplemented in blktap, based on lower-level char_dev.c (and kobject) primitives, but I'm not sure if the original goal is worth that ugliness. In any case, should I bother posting a version like that eventually, or would it have no chance of being accepted? Thanks & sorry for the noise. lacos