Re: [PATCH 2/6] xen-gntdev: Change page limit to be global instead of per-open

[Jeremy Fitzhardinge <jeremy@goop.org>]

On 12/15/2010 01:50 AM, Ian Campbell wrote:
> On Tue, 2010-12-14 at 21:42 +0000, Daniel De Graaf wrote:
>> On 12/14/2010 04:12 PM, Jeremy Fitzhardinge wrote:
>>> On 12/14/2010 06:55 AM, Daniel De Graaf wrote:
>>>> Because there is no limitation on how many times a user can open a
>>>> given device file, an per-file-description limit on the number of
>>>> pages granted offers little to no benefit. Change to a global limit
>>>> and remove the ioctl() as the parameter can now be changed via sysfs.
>>> Does anyone use this ioctl?  Wouldn't it be safer to replace it with a
>>> no-op version?
>>>
>>>     J
>>>
>> I do not know of any users. If it's preferred to replace with a noop ioctl
>> instead of the current -ENOSYS return, that's easy to do.
> It's called by xc_gnttab_set_max_grants in libxc, although I don't see
> any callers of that function.
>
> We should probably also remove the library function.

Seems like the right thing to do.  If its original semantics were iffy
and nobody is using it, then there's no point keeping vestigial code around.

    J