[Xen-devel] [PATCH 1/3] xen/privcmd: return -ENOSYS for unimplemented IOCTLs

2017-02-09 Thread Paul Durrant
The code goes so far as to set the default return code to -ENOSYS but
then overrides this to -EINVAL in the switch() statement's default
case.

This patch removes this pointless and incorrect override.

Signed-off-by: Paul Durrant 
---
Cc: Boris Ostrovsky 
Cc: Juergen Gross 
---
 drivers/xen/privcmd.c | 1 -
 1 file changed, 1 deletion(-)

diff --git a/drivers/xen/privcmd.c b/drivers/xen/privcmd.c
index 6e3306f..b4e5e27 100644
--- a/drivers/xen/privcmd.c
+++ b/drivers/xen/privcmd.c
@@ -572,7 +572,6 @@ static long privcmd_ioctl(struct file *file,
break;
 
default:
-   ret = -EINVAL;
break;
}
 
-- 
2.1.4


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Re: [Xen-devel] [PATCH 1/3] xen/privcmd: return -ENOSYS for unimplemented IOCTLs

2017-02-09 Thread Jan Beulich
>>> On 09.02.17 at 15:17,  wrote:
> The code goes so far as to set the default return code to -ENOSYS but
> then overrides this to -EINVAL in the switch() statement's default
> case.

If you already change this, isn't -ENOTTY the traditional way of
indicating unsupported ioctls?

Jan


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Re: [Xen-devel] [PATCH 1/3] xen/privcmd: return -ENOSYS for unimplemented IOCTLs

2017-02-09 Thread Boris Ostrovsky



On 02/09/2017 09:40 AM, Jan Beulich wrote:

On 09.02.17 at 15:17,  wrote:

The code goes so far as to set the default return code to -ENOSYS but
then overrides this to -EINVAL in the switch() statement's default
case.


If you already change this, isn't -ENOTTY the traditional way of
indicating unsupported ioctls?


In fact, a while ago David submitted a patch to do just that:

https://lists.xenproject.org/archives/html/xen-devel/2016-08/msg00744.html

but it never went anywhere.

My question is whether anyone might be relying on current error return 
behavior.



-boris

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Re: [Xen-devel] [PATCH 1/3] xen/privcmd: return -ENOSYS for unimplemented IOCTLs

2017-02-09 Thread Paul Durrant
> -Original Message-
> From: Boris Ostrovsky [mailto:boris.ostrov...@oracle.com]
> Sent: 09 February 2017 15:26
> To: Jan Beulich ; Paul Durrant
> 
> Cc: xen-de...@lists.xenproject.org; Juergen Gross ;
> linux-ker...@vger.kernel.org
> Subject: Re: [Xen-devel] [PATCH 1/3] xen/privcmd: return -ENOSYS for
> unimplemented IOCTLs
> 
> 
> 
> On 02/09/2017 09:40 AM, Jan Beulich wrote:
> >>>> On 09.02.17 at 15:17,  wrote:
> >> The code goes so far as to set the default return code to -ENOSYS but
> >> then overrides this to -EINVAL in the switch() statement's default
> >> case.
> >
> > If you already change this, isn't -ENOTTY the traditional way of
> > indicating unsupported ioctls?
> 
> In fact, a while ago David submitted a patch to do just that:
> 
> https://lists.xenproject.org/archives/html/xen-devel/2016-
> 08/msg00744.html
> 
> but it never went anywhere.
> 
> My question is whether anyone might be relying on current error return
> behavior.

I doubt it. It's certainly not a safe thing to do anyway. I'll change to 
-ENOTTY in v2 of the patch.

  Paul

> 
> 
> -boris

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