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Re: [Xen-devel] [PATCH linux-2.6.18-xen] blktap: make max # of tap devi

To: Jan Beulich <JBeulich@xxxxxxxxxx>
Subject: Re: [Xen-devel] [PATCH linux-2.6.18-xen] blktap: make max # of tap devices a module parameter
From: Laszlo Ersek <lersek@xxxxxxxxxx>
Date: Tue, 22 Feb 2011 18:34:47 +0100
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On 02/22/11 16:49, Jan Beulich wrote:
On 22.02.11 at 15:20, Laszlo Ersek<lersek@xxxxxxxxxx>  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

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