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Date:   Thu, 13 Oct 2022 06:47:22 +0200
From:   Greg KH <gregkh@linuxfoundation.org>
To:     Saurabh Singh Sengar <ssengar@linux.microsoft.com>
Cc:     ssengar@microsoft.com, kys@microsoft.com, haiyangz@microsoft.com,
        sthemmin@microsoft.com, wei.liu@kernel.org, decui@microsoft.com,
        longli@microsoft.com, linux-hyperv@vger.kernel.org,
        linux-kernel@vger.kernel.org, mikelley@microsoft.com
Subject: Re: [PATCH] uio_hv_generic: Enable support for slower vmbus device
 channels
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On Wed, Oct 12, 2022 at 09:15:15PM -0700, Saurabh Singh Sengar wrote:
> On Wed, Oct 12, 2022 at 05:54:07PM +0200, Greg KH wrote:
> > On Wed, Oct 12, 2022 at 05:52:05PM +0200, Greg KH wrote:
> > > On Wed, Oct 12, 2022 at 04:56:46AM -0700, Saurabh Sengar wrote:
> > > > This patch enables support for slower vmbus channels, which consist
> > > > of following 3 changes :
> > > > 	1. Support for hypercalls
> > > > 	2. Module params for recv/send buffer sizes
> > > > 	3. Module param for custom ring buffer sizes
> > > 
> > > Even if this all was ok, you are doing 3 things all in one change,
> > > that's not allowed at all, you all know this.
> > > 
> > > Anyway, no new module parameters, this is not the 1990's, we have much
> > > better ways to do this properly (hint, module parameters modify code,
> > > you want to modify the options of a specific device.)
> > 
> > Also, you give no good reason for why this is needed at all, nor how
> > anyone would use these options and why they would need to.
> > 
> > The kernel should "just work" and not require manual intervention by a
> > user.  Dynamically fix this based on the device, do NOT force a user to
> > have to attempt to "tune" anything, that will never work properly over
> > time, AND you are being lazy and forcing each individual user to do the
> > work, making more effort needed overall than just doing it properly in
> > the kernel.
> 
> Let me find a method if we can avoid using module parameters, this may result
> in hardcoding values in the vmbus driver code for various devices, giving less
> flexibilty to user.

A user should not be using the uio driver for any of that, so I doubt
this is a real issue :)

thanks,

greg k-h