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Date:   Mon, 31 Aug 2020 14:25:52 +0800
From:   Shuo A Liu <shuo.a.liu@intel.com>
To:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc:     <linux-kernel@vger.kernel.org>, "H . Peter Anvin" <hpa@zytor.com>,
        "Thomas Gleixner" <tglx@linutronix.de>,
        Ingo Molnar <mingo@redhat.com>,
        "Borislav Petkov" <bp@alien8.de>,
        Sean Christopherson <sean.j.christopherson@intel.com>,
        Yu Wang <yu1.wang@intel.com>,
        Reinette Chatre <reinette.chatre@intel.com>, <x86@kernel.org>,
        Zhi Wang <zhi.a.wang@intel.com>,
        Zhenyu Wang <zhenyuw@linux.intel.com>
Subject: Re: [PATCH 06/17] virt: acrn: Introduce VM management interfaces
Message-ID: <20200831062552.GH13723@shuo-intel.sh.intel.com>
References: <20200825024516.16766-1-shuo.a.liu@intel.com>
 <20200825024516.16766-7-shuo.a.liu@intel.com>
 <20200828102738.GC1470435@kroah.com>
 <20200829110436.GF13723@shuo-intel.sh.intel.com>
 <20200830072342.GA110796@kroah.com>
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Hi Greg,

On Sun 30.Aug'20 at  9:23:42 +0200, Greg Kroah-Hartman wrote:
>On Sat, Aug 29, 2020 at 07:04:36PM +0800, Shuo A Liu wrote:
>> On Fri 28.Aug'20 at 12:27:38 +0200, Greg Kroah-Hartman wrote:
>> > On Tue, Aug 25, 2020 at 10:45:06AM +0800, shuo.a.liu@intel.com wrote:
>> > > +	default:
>> > > +		pr_warn("Unknown IOCTL 0x%x!\n", cmd);
>> > > +		ret = -EINVAL;
>> >
>> > Wrong error value here, right?
>>
>> Right, it should be -ENOIOCTLCMD.
>
>It could, but really, just return the correct error for this, to prevent
>the core from having to do the conversion.
>
>The reviewers at Intel who should have read this before submitting it,
>know the correct value to return for an illegal ioctl, please go ask
>them.
>
>> However, i found many instances in kernel drivers return -EINVAL for no
>> ioctl command support. :)
>
>Then they too are wrong.  No need to add known bugs before the code is
>accepted.
>
>See the comments above the is_unrecognized_ioctl() in block/ioctl.c for
>all of the details and why -EINVAL is not the correct thing to do here.

Thanks for the information. -ENOTTY will be used.

Thanks
shuo